tag:theconversation.com,2011:/ca-fr/topics/sprinting-30261/articlesSprinting – La Conversation2022-09-28T12:32:30Ztag:theconversation.com,2011:article/1868012022-09-28T12:32:30Z2022-09-28T12:32:30ZYour mighty tendons help you sprint, jump and move – a genetic mutation in one key protein may increase athletic performance<figure><img src="https://images.theconversation.com/files/486922/original/file-20220927-26-skh2t7.jpg?ixlib=rb-1.1.0&rect=0%2C3%2C2139%2C1396&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A variant of Piezo1 may boost tendon strength and, subsequently, athletic ability.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/sprinters-in-motion-royalty-free-image/a0091-000172">Yellow Dog Productions/The Image Bank via Getty Images</a></span></figcaption></figure><p>The ability to move is an essential part of daily life. The <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/locomotor-system">locomotor, or musculoskeletal, system</a> of the body consists of muscles, bones, tendons, ligaments, joints, cartilage and other connective tissue. <a href="https://www.physio-pedia.com/Ageing_and_the_Locomotor_System">Loss of motor function</a> due to disease or injury can result in a lifetime of disability. In a rapidly aging society, maintaining and improving motor function can be a significant challenge for many people.</p>
<p>But there are ways to get around motor failure. As <a href="https://scholar.google.com/citations?user=6NvNu40AAAAJ&hl=en">molecular biologists</a> and <a href="https://www.researchgate.net/profile/Ryo-Nakamichi">orthopedic surgeons</a> who study the locomotor system, we believe one key part of it has been underestimated – the tendons.</p>
<p><a href="https://my.clevelandclinic.org/health/body/21738-tendon">Tendons</a> are tough tissues that connect muscle to bone. Tendons are what allow <a href="https://a-z-animals.com/blog/how-high-and-far-can-a-kangaroo-jump/">kangaroos</a> to jump over 25 feet (7.62 meters) high and run up to 40 mph (64 kph). While their leg muscles are small, the kangaroos’ highly developed and long tendons act like powerful springs. People can also jump higher if they squat down first because their tendons <a href="https://spaniardperformance.com/muscle-tendon-unit-characteristic-to-potenciate-training/">store elastic energy</a> that helps propel them upward.</p>
<p>In our research, we found that the presence of <a href="https://doi.org/10.1126/scitranslmed.abj5557">one particular protein in tendons</a> plays a key role in how tendons heal – and a genetic mutation in that protein may also enhance athletic performance.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/hdes6W76OOw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Tendons connect muscle to bone and are essential to movement.</span></figcaption>
</figure>
<h2>Identifying tendon proteins</h2>
<p>Tendon damage can be <a href="https://doi.org/10.1002/jor.22869">difficult to heal</a>. Approximately <a href="https://doi.org/10.1177/0363546520939897">60% of tendon injuries</a> lead to <a href="https://www.cdc.gov/arthritis/basics/osteoarthritis.htm">osteoarthritis</a>, a disease resulting from the breakdown of the cartilage in joints that can make movement even more difficult.</p>
<p>Developing treatments for tendon injuries has likewise been challenging. One of the reasons is that the proteins controlling the genes instructing the body to create tendons, called <a href="https://www.nature.com/scitable/definition/transcription-factor-167">transcription factors</a>, had been unknown.</p>
<p>To identify these proteins, we <a href="https://www.embrys.jp/embrys/html/MainMenu.html">created a catalog</a> of the 1,600 transcription factors in the human body. Based on this catalog, we examined what genes were active in the Achilles tendon of genetically engineered mice and found that a protein called Mkx was a central transcription factor for the health of tendons.</p>
<p>Researchers have long considered tendons to be inert tissue unable to contract like muscles can. But we discovered with our colleague, <a href="https://scholar.google.com/citations?user=2aSu29oAAAAJ&hl=en">Ardem Patapoutian</a>, the <a href="https://www.nobelprize.org/prizes/medicine/2021/advanced-information/">Nobel Prize-holder</a>, that one particular protein on the surface of tendon cells, Piezo1, can sense when the tendon is engaging in moderate exercise and stimulate the Mkx transcription factor.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/wtkKyZ9vjq4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The discovery of Piezo1’s role in the perception of touch won the 2021 Nobel Prize in physiology or medicine.</span></figcaption>
</figure>
<h2>Piezo1 and athletic performance</h2>
<p>We then wondered about the role that Piezo1 plays in athletic performance. We were particularly interested in a variant of Piezo1 called E756del, which is found in around <a href="https://doi.org/10.1016/j.cell.2018.02.047">a third of people of African descent</a> and thought to play a potential role in <a href="https://doi.org/10.1038/s41551-021-00716-x">how high people can jump</a>. </p>
<p>So we genetically engineered mice to produce an equivalent mouse version of Piezo1 E756del proteins throughout their body and then <a href="https://doi.org/10.1126/scitranslmed.abj5557">tested their performance</a> on different physical activities, including long jump and running on a treadmill. Surprisingly, we found that mice with E756del proteins were able to jump about 1.6 times farther without training than mice without the E756del proteins. Mice with Piezo1 in their tendons were also able to run about 1.2 times faster than those without Piezo1.</p>
<p>To identify which body part was producing this jumping ability, we then created mice that produced Piezo1 proteins either in their muscles or their tendons. The results were even more surprising: Mice with Piezo1 in their tendons improved in their jumping ability just as well as mice with Piezo1 throughout their entire body. Mice with Piezo1 only in their muscles, however, did not have any improvement in jumping ability.</p>
<p>We then decided to test the role of Piezo1 in human athletic performance. In collaboration with the <a href="http://www.athlomeconsortium.org/">Athlome Consortium</a>, an international athletic genomics organization, we compared the prevalence of the gene that codes for E756del in 91 Olympic-level Jamaican sprinters and 108 people in the general population in Jamaica. We found that 54% of Jamaican sprinters had an active gene for E756del, compared to just approximately 30% of the general population.</p>
<p>Our findings show that changing a single protein, in this case E756del, can play a role in athletic performance. Further research on tendons and other parts of the human motor systems could help improve treatments for musculoskeletal conditions.</p><img src="https://counter.theconversation.com/content/186801/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hiroshi Asahara receives funding from National Institute of Health, Japan Society for the Promotion of Science, Japan Agency for Medical Research and Development.</span></em></p><p class="fine-print"><em><span>Ryo Nakamichi does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The discovery of the role that the protein Piezo1 plays in touch and body awareness won the 2021 Nobel Prize in physiology or medicine. Piezo1 may also be a significant player in motor function.Hiroshi Asahara, Professor of Molecular Medicine, The Scripps Research InstituteRyo Nakamichi, Postdoctoral Researcher in Molecular Medicine, The Scripps Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1628322021-07-21T19:27:14Z2021-07-21T19:27:14ZAre middle lanes fastest in track and field? Data from 8,000 racers shows not so much<figure><img src="https://images.theconversation.com/files/411575/original/file-20210715-32740-t68wyj.jpg?ixlib=rb-1.1.0&rect=0%2C123%2C5150%2C3299&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The fastest runners are usually rewarded with the middle lanes. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/male-athltes-starting-from-blocks-on-track-royalty-free-image/457893067?adppopup=true"> Michael H/Stone vie Getty Images</a></span></figcaption></figure><p>As a short-distance track and field runner in high school and college, I often found myself wondering which of the eight or sometimes nine lanes on the track was the fastest. It was conventional wisdom that the middle lanes – lanes three through six – were the best.</p>
<p>This idea, in a way, is baked into the rules of track and field. In events with multiple heats – from the <a href="http://www.ncaapublications.com/p-4623-2021-2022-cross-country-and-track-and-field-rules.aspx">college level</a> all the way to the <a href="https://www.worldathletics.org/about-iaaf/documents/book-of-rules">Olympics</a> – the people who run faster times in earlier heats are assigned to middle lanes in later heats. In other words, the fastest runners are rewarded with what are, supposedly, better lane assignments. </p>
<p>My short-lived track career is long behind me, but in my <a href="http://www.middlebury.edu/academics/econ/faculty_staff_officehours/node/538091">professional life as an economist</a>, I think a great deal about using statistics to extract meaning from data. With the Olympics on my mind, I decided to examine the validity of lane assignment folklore from my days as a sprinter. </p>
<p>Using 20 years of track and field data from the <a href="https://www.worldathletics.org/">International Association of Athletics Federations</a>, I found that the long-held beliefs about lane advantages are not supported by the <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3801883">data</a>. And in fact, for the 200-meter sprint, the evidence suggests that lanes often perceived as the least desirable are actually the fastest.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/411576/original/file-20210715-15-137tynv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Runners in a staggered spacing coming around a turn." src="https://images.theconversation.com/files/411576/original/file-20210715-15-137tynv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/411576/original/file-20210715-15-137tynv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=358&fit=crop&dpr=1 600w, https://images.theconversation.com/files/411576/original/file-20210715-15-137tynv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=358&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/411576/original/file-20210715-15-137tynv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=358&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/411576/original/file-20210715-15-137tynv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=450&fit=crop&dpr=1 754w, https://images.theconversation.com/files/411576/original/file-20210715-15-137tynv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=450&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/411576/original/file-20210715-15-137tynv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=450&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tighter turns and staggered starting positions supposedly make inside and outside lanes slower.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Crawford,_Dzingai_200_m_Berlin_2009.jpg#/media/File:Crawford,_Dzingai_200_m_Berlin_2009.jpg">André Zehetbauer/WikimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Myth of the middle lane</h2>
<p>If lane assignments do matter, their impact would be most noticeable for events where the runners have to stay in their lanes for all of, or at least a large part of, the race, like 100-meter, 200-meter, 400-meter and 800-meter events. </p>
<p>In my experience, the myth of the middle lane being the fastest is most commonly associated with fast-paced races that also include corners, so the 200 and 400. There are two rationales behind this point of view, and they have to do with why the inside and outside lanes are bad, more than why middle lanes are better. </p>
<p>The reasoning for why inside lanes are bad is that in races with turns, the inside lanes are slower because the corners are too tight. Indeed, researchers who study the biomechanics of running find that tighter corners do <a href="https://doi.org/10.1242/jeb.133488">slow runners down</a>.</p>
<p>The rationale behind slow outside lanes has to do with the <a href="https://www.sbnation.com/2016/8/15/12486250/rio-2106-track-athletics-lane-staggered-start-400-record-wayde-van-niekerk">staggered starts</a> required to make sure each racer runs the same distance. Due to this staggering, runners in the outside lanes cannot see their competitors for the majority of the race. The thinking goes that outside runners may have <a href="https://www.sbnation.com/2016/8/15/12486250/rio-2106-track-athletics-lane-staggered-start-400-record-wayde-van-niekerk">less motivation to chase competitors</a> or have <a href="https://www.livescience.com/55768-track-outside-lanes-olympic-running-swimming.html">difficulty gauging their speed</a> compared to the pack if they can’t see other racers.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/411577/original/file-20210715-32887-6l8zkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Racers at the starting blocks of a 200m sprint." src="https://images.theconversation.com/files/411577/original/file-20210715-32887-6l8zkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/411577/original/file-20210715-32887-6l8zkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/411577/original/file-20210715-32887-6l8zkl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/411577/original/file-20210715-32887-6l8zkl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/411577/original/file-20210715-32887-6l8zkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/411577/original/file-20210715-32887-6l8zkl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/411577/original/file-20210715-32887-6l8zkl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In the 200-meter sprint, where racers have a staggered start and go around one turn, the outside lane seems to be the fastest.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nickwebb/7734445082/in/set-72157630789298326">Nick Webb/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Not all lanes are the same</h2>
<p>In most races, the <a href="https://www.worldathletics.org/about-iaaf/documents/book-of-rules">fastest runners are assigned to the middle lanes</a> in accordance with the competition rules. Not surprisingly, the fastest runners – who are in the middle lanes – often win. Are these racers winning because those lanes are the fastest or because those runners tend to be the fastest? </p>
<p>Similar to the idea behind clinical trials for a drug, the ideal way to test lane advantages would be to randomly assign runners to lanes and see how they do on average. Thankfully, there is a subset of race data that does this: Typically, runners are randomly assigned to lanes in the first heats of events. By using data only from first heats of elite track and field events, I was able eliminate the bias from faster runners being assigned to certain lanes. </p>
<p>Using roughly 8,000 individual race results, I found that the “middle is best” belief is not well supported by the data.</p>
<p>For the 100 – which is run on a straightaway – I found no evidence of lane advantages. The myth is less prevalent here, though, so this lack of difference isn’t surprising.</p>
<p>The most striking counterpoint to the “middle is best” assumption is the 200. I found that it is in fact outside lanes that are associated with faster race times – on average lane eight is roughly 0.2 seconds faster than lane two. This is sizable for a race in which the <a href="https://www.worldathletics.org/records/by-discipline/sprints/200-metres/outdoor/men">world record is 19.19 seconds</a>. Faster outside lanes make sense biomechanically as tighter corners produce slower race times. But the result seems to disprove the idea that not seeing competitors can slow a runner down.</p>
<p>In the 400, I found no evidence that middle lanes are fastest. All lanes seem to be roughly equal. It is worth noting that there is more variability in 400-meter times, so it is harder to detect small effects, if they exist. But even this nondifference between lanes in the 400 is striking. </p>
<p>In the 2016 Olympics, people <a href="https://www.bbc.com/news/newsbeat-37083059">marveled when Wayde Van Niekerk won the 400 final from lane eight</a>, the farthest outside lane. The astonishment stemmed from the belief that lane eight puts runners at a disadvantage. The data doesn’t support this. But what is impressive about Van Niekerk’s win is that he was one of the slower runners to qualify for the final – that’s why he was assigned to one of the “least desirable” lanes. </p>
<p>The last event I looked at, the 800, is distinct from the other events above. It has what is called a “lane break,” which is where runners must remain in their assigned lanes for the first 100 meters but are then free to run in any lane they wish. Since the inside lane of a track covers the shortest distance, runners in outside lanes move inward after the break. As they do this, they may have to run a tiny bit farther than their competitors and jockey for position with runners who are already in the inside lanes. I found that racers who start at the very inside lanes ran the fastest times. While outside lanes might have a small advantage over the first 100 meters, runners who have an established position on the inside of the track seem to have an overall advantage. </p>
<p>Next time you’re watching any of the shorter track and field events at the Olympics, listen to see if anyone repeats the old adage that the middle lanes are fastest. The data says this isn’t true, so if someone in the outside lanes takes a surprise gold, you’ll know to be surprised not because of their lane assignment, but because they were a slow qualifier.</p>
<p>[<em>Insight, in your inbox each day.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=insight">You can get it with The Conversation’s email newsletter</a>.]</p><img src="https://counter.theconversation.com/content/162832/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David R. Munro does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>In track and field, it’s a common belief that middle lanes are the fastest. But according to the data, middle lanes aren’t better, and in the 200-meter sprint, outside lanes might even be faster.David R. Munro, Assistant Professor of Economics, MiddleburyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1341052020-05-15T12:13:43Z2020-05-15T12:13:43ZRobo-boot concept promises 50% faster running<figure><img src="https://images.theconversation.com/files/334576/original/file-20200513-82379-zd38rg.jpg?ixlib=rb-1.1.0&rect=8%2C4%2C2867%2C2871&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The old idea of running with springs on your feet gets a high-tech makeover.</span> <span class="attribution"><span class="source">Krisztina Braun</span></span></figcaption></figure><p>No matter how well designed, there are no running shoes that allow runners to keep up with cyclists. The bicycle was a key invention that doubled human-powered speed. But what if a new kind of shoe could allow people to run faster by mimicking cycling mechanics?</p>
<p>This is the question my students in <a href="https://lab.vanderbilt.edu/arclab/">Vanderbilt’s Center for Rehabilitation Engineering & Assistive Technology</a> and <a href="https://scholar.google.com/citations?user=AmwZkPAAAAAJ&hl=en">I</a> explored as we developed a new theory of <a href="http://doi.org/10.1126/sciadv.aay1950">spring-driven robotic exoskeletons</a>. We came up with a concept for a new type of lower limb exoskeleton that could allow the world’s fastest human to reach a speed of 18 meters per second or about 40 miles per hour.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/323440/original/file-20200326-132974-5gjd60.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/323440/original/file-20200326-132974-5gjd60.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=227&fit=crop&dpr=1 600w, https://images.theconversation.com/files/323440/original/file-20200326-132974-5gjd60.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=227&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/323440/original/file-20200326-132974-5gjd60.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=227&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/323440/original/file-20200326-132974-5gjd60.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=286&fit=crop&dpr=1 754w, https://images.theconversation.com/files/323440/original/file-20200326-132974-5gjd60.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=286&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/323440/original/file-20200326-132974-5gjd60.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=286&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Robo-boots allow the legs to supply energy in the air during running, similar to the pedaling mechanism in cycling.</span>
<span class="attribution"><span class="source">A. Sutrisno and D. J. Braun</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The cutting edge of today’s running shoes is Nike’s Vaporfly, which allows runners to use <a href="https://www.youtube.com/watch?v=wVXrIaPuP7c">4% less energy</a> than standard running shoes. Three-time Olympic medalist Eliud Kipchoge recently wore them to <a href="https://www.nytimes.com/2019/10/12/sports/eliud-kipchoge-marathon-record.html">run a marathon in under two hours</a>. Though the Vaporfly upended the world of professional running by increasing the efficiency of standard running shoes, it doesn’t provide the advantages of cycling or otherwise fundamentally alter the physics of running.</p>
<p>There has been a lot of research and development in <a href="https://doi.org/10.1186/s12984-020-00663-9">robotic exoskeletons</a> that augment human power. These use actuators and external energy: motors and batteries. But they haven’t helped humans run faster. Springs have also been used to make <a href="https://www.scientificamerican.com/article/blade-runners-do-high-tech-prostheses-give-runners-an-unfair-advantage/">high-tech prostheses for paralympic running</a>, but have <a href="https://www.theguardian.com/science/2009/nov/04/prosthetics-athletes-oscar-pistorius">not been shown to provide an unfair advantage</a> compared to legs. For human-powered speed, the bicycle has been the reigning champion for over a century.</p>
<h2>Running versus cycling</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/331880/original/file-20200430-42942-ah6qur.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/331880/original/file-20200430-42942-ah6qur.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331880/original/file-20200430-42942-ah6qur.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331880/original/file-20200430-42942-ah6qur.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331880/original/file-20200430-42942-ah6qur.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331880/original/file-20200430-42942-ah6qur.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331880/original/file-20200430-42942-ah6qur.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The precursor to the modern bicycle, dubbed the hobby horse, was invented in 1817 by Baron Karl von Drais.</span>
<span class="attribution"><a class="source" href="https://flickr.com/photos/cstmweb/3322870427/in/photolist-2fbttVS-LigA4-64CzBr-Wbzddz-xqEBKs-W8accJ-WbzerM-VVKpT5-Wbzfgn">Canada Science and Technology Museum/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p><a href="https://www.wired.com/2011/02/0217draisine-sauerbrun-bicycle-forerunner/">The first running machine</a> was a bicycle with no pedals. It reduced the energy cost of running by supporting the body’s weight on a seat and using wheels to avoid the inevitable energy loss when runners step. </p>
<p>But early bicycles <a href="https://doi.org/10.1098/rspb.2001.1662">did not allow cyclists to move faster than runners</a> because the rider propelled himself by pushing against the ground with his legs – just like running. What changed the game for bicycling was the invention of <a href="https://www.bbc.co.uk/history/historic_figures/macmillan_kirkpatrick.shtml">the pedaling mechanism</a>, which allowed the legs to propel the rider continuously rather than only when the foot hits the ground.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/331881/original/file-20200430-42929-1ek8v69.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/331881/original/file-20200430-42929-1ek8v69.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=667&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331881/original/file-20200430-42929-1ek8v69.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=667&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331881/original/file-20200430-42929-1ek8v69.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=667&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331881/original/file-20200430-42929-1ek8v69.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=839&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331881/original/file-20200430-42929-1ek8v69.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=839&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331881/original/file-20200430-42929-1ek8v69.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=839&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In 1890, Nicolas Yagn invented a spring-leg that supported the weight of a person’s body.</span>
<span class="attribution"><a class="source" href="https://pdfpiw.uspto.gov/.piw?docid=00420179&PageNum=3&IDKey=3EBC73AAF8C8&HomeUrl=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1%2526Sect2=HITOFF%2526d=PALL%2526p=1%2526u=%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r=1%2526f=G%2526l=50%2526s1=0420179.PN.%2526OS=PN/0420179%2526RS=PN/0420179">USPTO</a></span>
</figcaption>
</figure>
<p>The bicycle’s speed advantage over running has not endured for lack of trying. People have been imagining <a href="https://patents.google.com/patent/US420179A/en">spring legs</a> and refining <a href="https://www.youtube.com/watch?v=B5V356k-9a8">running springs</a> for generations, but these springs are not like a bicycle with pedals because they don’t allow the legs to supply energy when they’re off the ground.</p>
<h2>The robo-boot</h2>
<p>To apply the advantage of cycling to running, we came up with a concept for a new type of robo-boot that emulates the function of bicycle pedals. Using the robo-boot, runners supply energy by compressing a spring with each leg while it’s in the air. With each footstep, the spring releases its stored energy by pushing against the ground faster and stronger than the legs could otherwise do. </p>
<p>We found that an ideal robo-boot would allow the fastest runner on Earth to use his legs 96% of the step time to run faster than 20 meters per second, comparable to the top speed of cycling. A more practical robo-boot that is used only about 60% of the step time could still help a runner reach a top speed of 18 meters per second. That’s 50% faster than the world record speed of 12 meters per second in the 100 meter sprint.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/334833/original/file-20200513-156629-1f0ypsv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/334833/original/file-20200513-156629-1f0ypsv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/334833/original/file-20200513-156629-1f0ypsv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=436&fit=crop&dpr=1 600w, https://images.theconversation.com/files/334833/original/file-20200513-156629-1f0ypsv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=436&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/334833/original/file-20200513-156629-1f0ypsv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=436&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/334833/original/file-20200513-156629-1f0ypsv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=548&fit=crop&dpr=1 754w, https://images.theconversation.com/files/334833/original/file-20200513-156629-1f0ypsv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=548&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/334833/original/file-20200513-156629-1f0ypsv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=548&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Top speed of human-powered locomotion.</span>
<span class="attribution"><span class="source">Adapted from A. Sutrisno, D. J. Braun, How to run 50% faster without external energy, vol. 6, no. 13, eaay1950, 2020.</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The high-tech component of the robo-boot is a <a href="https://lab.vanderbilt.edu/arclab/research/">variable stiffness spring</a> that can increase its stiffness without changing its stored energy. The stiffness of the spring determines how forcefully it can push against the ground to accelerate the runner’s body – the stiffer the spring, the greater the force given the same spring compression.</p>
<p>Conventional springs like those in retractable pens have a constant stiffness based on the spring’s material, shape and size. <a href="https://doi.org/10.1109/TRO.2019.2929686">Variable stiffness springs</a> are a special type of spring that can change shape or size. One type of variable stiffness spring increases stiffness by getting shorter. <a href="https://doi.org/10.1109/TRO.2018.2872284">A mechanism shortens the spring</a> by moving the spring’s attachment point from its end to its middle. The mechanism in the robo-boot shortens the spring as the runner extends her leg in the air.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/332396/original/file-20200504-83721-1rx21oh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/332396/original/file-20200504-83721-1rx21oh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/332396/original/file-20200504-83721-1rx21oh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=171&fit=crop&dpr=1 600w, https://images.theconversation.com/files/332396/original/file-20200504-83721-1rx21oh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=171&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/332396/original/file-20200504-83721-1rx21oh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=171&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/332396/original/file-20200504-83721-1rx21oh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=215&fit=crop&dpr=1 754w, https://images.theconversation.com/files/332396/original/file-20200504-83721-1rx21oh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=215&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/332396/original/file-20200504-83721-1rx21oh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=215&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Running with robo-boots.</span>
<span class="attribution"><span class="source">Adapted from A. Sutrisno, D. J. Braun, How to run 50% faster without external energy, vol. 6, no. 13, eaay1950, 2020.</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Increasing the stiffness of the spring as the runner picks up speed is analogous to switching to a higher gear on a bike as a cyclist rides faster. This allows runners to supply more energy and bypass the biomechanical limitation of supplying energy only during the short ground contact time of high-speed running.</p>
<h2>Next steps</h2>
<p>Modern racing bikes nearly double the top speed of running. Robo-boots that leverage bicycle mechanics could similarly allow people to run faster without hefty motors and batteries. We hope to have an initial robo-boot prototype within a year. But just as it took many years after their invention for bicycles to take full advantage of their unique mechanics, it will take some time to make a robo-boot that can achieve its full potential.</p>
<p>These more portable human-powered devices could enable more widespread adoption of wearable robotic technology, and could push the boundaries of search and rescue, law enforcement and sports. What would it mean for first responders to be able to move 50% faster? Would a running shoe that provides a 50% speed increase lead to a new event at the Olympics similar to ice skating and bicycle racing?</p>
<p>Using science and advanced robotics technology, we’re able to envision next generation robo-boots that offer the first major boost to human-powered movement since the invention of the bicycle pedal in the 19th century.</p>
<p>[<em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>.]</p><img src="https://counter.theconversation.com/content/134105/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>I am an inventor on a pending patent related to this work filed by Vanderbilt University.</span></em></p>A high-tech twist on an old idea – running on springs – could give human-powered movement its biggest boost in more than a century.David Braun, Assistant Professor of Mechanical Engineering and Computer Engineering, Vanderbilt UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1276342019-11-25T14:52:41Z2019-11-25T14:52:41ZRunning shoes: how science can help you to run faster and more efficiently<figure><img src="https://images.theconversation.com/files/303322/original/file-20191124-74557-16zkcnl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The key to record-breaking performances?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/man-runner-on-street-be-running-1129471388">Shutterstock</a></span></figcaption></figure><p>Long-distance running times are dropping – and the first <a href="https://www.bbc.co.uk/sport/athletics/50025543">sub-two hour marathon</a> was completed recently by Kenyan athlete, Eliud Kipchoge. Some are arguing that <a href="https://theconversation.com/wafer-thin-bicycles-speedy-shorts-go-faster-trainers-controversial-technology-in-sport-126301">innovations</a> in trainer design are playing a pivotal role in these <a href="https://www.bbc.co.uk/sport/athletics/50041037">improvements</a>. But what is the science behind these elite running shoes? Can they really make such a big difference? And can they get even better?</p>
<p>Over the last two decades, there has been <a href="https://www.mdpi.com/journal/applsci/special_issues/Sports_Materials">growing focus</a> on the <a href="http://sportsengineering.org/">engineering</a> of sports equipment, <a href="https://www.springer.com/journal/12283">including running</a> <a href="https://uk.sagepub.com/en-gb/eur/journal/proceedings-institution-mechanical-engineers-part-p-journal-sports-engineering">shoes</a>. But while we are seeing rapid development in this area, these steps are often incremental improvements rather than massive strides of change.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/f_lfp3C_PTQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>The first ever running shoe appeared about <a href="https://mentalitch.com/the-history-of-running-shoes/">200 years ago</a> and <a href="https://www.runnersworld.com/gear/a20787065/a-brief-history-of-the-running-shoe/">both materials and design</a> have <a href="http://news.bbc.co.uk/sportacademy/hi/sa/athletics/features/newsid_3935000/3935703.stm">improved enormously</a> since then. But if you consider the changes on a year-to-year basis, the variances are fractional. They do, however, add up.</p>
<h2>Preventing injury</h2>
<p>A running shoe should protect the foot and the runner from injury. It provides stabilisation of the foot and protects skin from damage. It should also limit potentially harmful impact forces as the foot strikes the ground, while returning energy to the runner.</p>
<p>Running shoes are designed in a way that improves running efficiency. Science suggests that if you can reduce the energy it takes to run, then in theory, you should be able to run faster and for a longer period.</p>
<p>To do this, a number of techniques can be adopted. First, we can <a href="https://link.springer.com/article/10.1007/s40279-017-0811-2">reduce the mass of a shoe</a> to <a href="https://shapeamerica.tandfonline.com/doi/abs/10.1080/02640414.2019.1633837#.Xdfx00x2tMs">make it lighter</a>. This will allow a runner to swing their legs more efficiently. Another claim is that if there is more cushioning in the midsole, then an athlete can run with <a href="https://link.springer.com/article/10.1007/s40279-017-0811-2">straighter legs</a>, again making them more efficient.</p>
<p>Adding <a href="https://link.springer.com/article/10.1007/s40279-017-0811-2">stiff plates</a> <a href="https://shapeamerica.tandfonline.com/doi/abs/10.1080/02640414.2019.1633837#.Xdfx00x2tMs">within</a> <a href="http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.453.6692&rep=rep1&type=pdf">the</a> [midsole], may also help an athlete to run better by redistributing positive lower limb joint work from the knee to the joint of your toes <a href="https://www.sciencedirect.com/science/article/abs/pii/S1440244019303822">above the ball of your foot</a>. These stiff plates may also store and return energy to the runner.</p>
<p>In general, when we compress this midsole, and then release it, we want as much energy as possible to be returned. The more energy that is returned, the more efficiently an athlete should be able to run.</p>
<p>It can, of course, be difficult to design tests that systematically explore all these factors, but they are being explored by science.</p>
<h2>Every runner is different</h2>
<p>Major sporting brands spend a lot of time and resources designing and tuning running shoes, but the biggest challenge they face is <a href="https://link.springer.com/article/10.1007/s12283-015-0183-5">the fact that everyone is different</a>.</p>
<p>The design and engineering that goes into a running shoe is quite heavily dependent on the runner, and their requirements. Each person will have his or her own running style and, of course, every foot is unique. There is never going to be a one-size-fits-all in shoe design.</p>
<p>A sprinting shoe would also be entirely different to a marathon shoe, for example. Marathon footwear needs cushioning to reduce injury risk from many impacts over a long distance; while a sprinting shoe could benefit from <a href="https://www.tandfonline.com/doi/abs/10.1080/14763140408522830?casa_token=_xSwMcssHSQAAAAA:XxnpqUFesAGenlmIcHehViKniuo_PaVqUWew2w6onq4VrtWMl0dOa3Upy3uGkxaVY372yUH1lPC0Qg">being stiffer</a> without necessarily requiring as much cushioning.</p>
<p>Similarly, some runners strike the ground right on their heel. These “rear-foot strikers” likely need more cushioning. Others will strike more on their forefoot. They are probably less concerned with cushioning, and could benefit from a more minimalist running shoe, or <a href="https://www.nature.com/articles/nature08723">even running barefoot</a>.</p>
<h2>Testing for excellence</h2>
<p>Testing falls into two main areas. The first is engineering testing: testing of the design and materials. This involves testing the shoe in isolation.</p>
<p>For example, you might want to look at the ageing of a shoe. This might involve putting an artificial foot in the shoe and compressing it thousands and thousands of times to mimic someone running, and then seeing how the <a href="https://journals.sagepub.com/doi/full/10.1177/1754337118824001?casa_token=P_mdA42e_IsAAAAA%3A9N0z9VXRxIBBTEaOwdLBr2Rllmx7wx9bMt-dAz7tyv4Dp_EA2e7JnP2UjvUe5Jf4y82aA7cCrQ5L">properties change</a> over <a href="https://www.tandfonline.com/doi/full/10.1080/19424280.2016.1228702?casa_token=a9yrrPie9XUAAAAA%3AxajCQBAZCDxchX0p1aVEQ7FSJ6nirzDovFwr6OhPL7NAVm7WNS9KpvYvxH3DD12iCOXvkJP0Bv9n">time</a>. </p>
<p>But you should also explore the interaction of the shoe with the athlete, investigating the effect the footwear has on the runner, their performance and the general physiological state of the individual.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/303321/original/file-20191124-74562-siq57d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/303321/original/file-20191124-74562-siq57d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/303321/original/file-20191124-74562-siq57d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/303321/original/file-20191124-74562-siq57d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/303321/original/file-20191124-74562-siq57d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/303321/original/file-20191124-74562-siq57d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/303321/original/file-20191124-74562-siq57d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">What’s the right shoe for you?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/man-tying-running-shoes-670262131">Shutterstock</a></span>
</figcaption>
</figure>
<p>To test this, athletes might be asked to run over force plates while being filmed with a motion capture system, to see how the footwear influences their movement and <a href="https://www.sciencedirect.com/science/article/abs/pii/0021929087903241">ground reaction forces</a>. We could also look at the injury risks at this time.</p>
<p>You might also have participants running on treadmills and then <a href="https://link.springer.com/article/10.1007/s40279-017-0811-2">monitor</a> their <a href="https://shapeamerica.tandfonline.com/doi/abs/10.1080/02640414.2019.1633837">oxygen levels</a>. In these types of experiments you can see how efficient they are at running with different kinds of footwear.</p>
<h2>Material gains</h2>
<p>Materials are probably the most crucial thing in footwear science. Many of the latest innovations in running shoes are based around the materials being used.</p>
<p>The shape of a shoe is more or less fixed to the shape of the foot. But you might make the midsole thicker and from a softer, more resilient material, providing a bigger distance for it to compress over, so it can absorb and <a href="https://link.springer.com/article/10.1007/s40279-017-0811-2">return more energy</a>. </p>
<p>You can consider a range of things when looking at different materials. You might want to consider using lighter materials, materials that return more energy or materials, which allow the shoe to be <a href="https://www.mdpi.com/2076-3417/8/6/941">more fitted to the foot</a>.</p>
<p>Running shoe midsoles are typically made from moulded materials like EVA foam. The bottom of a shoe needs to be rubbery and provide grip, and often textiles go on top to form the upper.</p>
<h2>The future of footwear</h2>
<p>I believe the future of running footwear is in sustainability and customisation. In future, people could be able to design their own shoes to their preference. I also believe shoes will be designed to better suit the needs of the runner. For example, we might monitor how someone runs in the lab and then design a pair of shoes specifically for them. </p>
<p>One thing is certain, though. We still do not fully understand what makes the best running shoe and science is key. We still have a long race ahead of us.</p><img src="https://counter.theconversation.com/content/127634/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Allen works for Manchester Metropolitan University. He has received contract research funding from sports brands for work on materials in relation to footwear. He worked for Adidas in 2005. </span></em></p>As record running times drop, what role is footwear playing?Thomas Allen, Senior Lecturer, Department of Engineering, Manchester Metropolitan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1201352019-09-27T08:10:57Z2019-09-27T08:10:57ZWorld Athletics Championships: study busts myth of the hurdler’s start<p>Runners in the 2019 World <a href="https://theconversation.com/uk/topics/athletics-3374">Athletics</a> Championships in Qatar will know that, when winning depends on a difference of a few thousandths of a second, getting a good start is crucial. Intuition suggests the way athletes start a race should depend on the event. Hurdlers, for example, need to clear their first barrier after only seven or eight steps, while sprinters are faced with a clear track all the way to the finish line.</p>
<p>In fact, it’s a common belief that hurdlers “pop up” out of the blocks. That is, they adopt an upright posture more quickly because they need to clear that first hurdle, compared to sprinters’ continued forward lean for acceleration. <a href="http://ucoach.com/assets/uploads/files/Hurdling_For_Young_Athletes_2011.pdf">Coaching texts</a> have kept the idea of this apparent difference alive. But, until now, no one had directly compared exactly how hurdlers and sprinters start. Our <a href="https://www.frontiersin.org/articles/10.3389/fspor.2019.00023/full">newly published study</a> suggests that, in reality, the two types of athlete start their races in quite a similar way. So there is lots to learn from each other about how they could improve their performance.</p>
<p>Our study, conducted at the most recent World Indoor Championships in Birmingham 2018, for the first time analysed in depth the sprint start techniques of the very best male athletes in the world. It gives an impression of how top athletes perform when gold medals are on the line. The project was led by our colleague <a href="https://scholar.google.co.uk/citations?user=78NK8vIAAAAJ&hl=en">Dr Athanassios Bissas</a> and backed by the <a href="https://www.iaaf.org/news/press-release/biomechanics-research-world-indoor-championsh">International Association of Athletics Federations</a>.</p>
<p>Coaches and scientists like to break down the sprinting action into different phases to help with their analyses. The sprint start is often divided into the initial push with both feet on the blocks, followed by the phase in which only the front foot remains pushing on the blocks. Then each step the athlete takes is composed of a flight phase and a ground contact phase. </p>
<p>Each of these phases can be analysed in minute detail to try to shave those vital fractions of a second from the final race time. Using four high-speed cameras around the arena, we created a detailed computer model of each of our male athletes. These were then combined to create overall models of performance separately for sprinters and hurdlers, for comparison.</p>
<p>Athletes can choose how close to the starting line to place their starting blocks. They typically want to be as close to the line as possible without being too hunched up in a way that would negatively affect their start. Our study shows that hurdlers set their blocks up nearer to the line than sprinters, probably because they are aware of the need to reach the first hurdle in only seven steps without having to overstretch.</p>
<p>By the time the athletes have left the blocks, the hurdlers have pushed themselves slightly further forwards and upwards than the sprinters. But overall, their body positions are remarkably similar.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/293248/original/file-20190919-22450-bruh40.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/293248/original/file-20190919-22450-bruh40.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/293248/original/file-20190919-22450-bruh40.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/293248/original/file-20190919-22450-bruh40.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/293248/original/file-20190919-22450-bruh40.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/293248/original/file-20190919-22450-bruh40.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/293248/original/file-20190919-22450-bruh40.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/293248/original/file-20190919-22450-bruh40.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sprinter’s (black stick figure) and hurdler’s (grey stick figure) body positions in the set position and when each foot comes off the starting block.</span>
<span class="attribution"><span class="source">Bezodis et al. 2019</span></span>
</figcaption>
</figure>
<p>At first foot contact with the track, upper bodies of hurdlers are in a more upright position than that of the sprinters, but their lower body positions are all similar. By the time the athletes have left the ground, both their upper and lower body positions match more closely across the groups. This pattern of differences repeats for the first three steps that we measured.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/293249/original/file-20190919-22433-sx0cl1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/293249/original/file-20190919-22433-sx0cl1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/293249/original/file-20190919-22433-sx0cl1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=292&fit=crop&dpr=1 600w, https://images.theconversation.com/files/293249/original/file-20190919-22433-sx0cl1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=292&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/293249/original/file-20190919-22433-sx0cl1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=292&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/293249/original/file-20190919-22433-sx0cl1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=367&fit=crop&dpr=1 754w, https://images.theconversation.com/files/293249/original/file-20190919-22433-sx0cl1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=367&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/293249/original/file-20190919-22433-sx0cl1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=367&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sprinter’s (black stick figure) and hurdler’s (grey stick figure) body positions at touchdown and take-off of the first step after the blocks.</span>
<span class="attribution"><span class="source">Bezodis et al. 2019</span></span>
</figcaption>
</figure>
<p>The difference in upper body positions when the athletes’ feet hit the track is probably what creates the impression that there are large differences between sprinters and hurdlers. It’s what makes the hurdlers look like they are indeed “popping up”. But the hurdlers’ techniques looks much like that of the sprinters by the end of the first ground contact.</p>
<p>Extensive <a href="https://www.ncbi.nlm.nih.gov/pubmed/21364480">previous</a> research <a href="https://link.springer.com/article/10.1007/s40279-019-01138-1">on sprinters</a> has shown how effective they are at projecting themselves forwards rather than upwards from the blocks. The similarities that we have found suggest that hurdlers are almost as effective at this forward propulsion, despite the imposing physical barriers in front of them.</p>
<h2>Implications for training</h2>
<p>We think our study has two major implications. First, it could be a lot easier for athletes to transfer from sprinting to hurdling than currently thought. There is little in our work to suggest that sprinters would struggle with performing an effective approach to the first hurdle. Giving hurdles a try might allow some sprinters to discover an event that they are more suited to.</p>
<p>Second, hurdlers can learn much about effective acceleration from sprinters. They should be encouraged to explore the range of their capabilities with and without hurdles. Coaches should focus on the similarities between the two events, rather than the perceived differences. This would offer more opportunities for coaches and athletes to improve.</p>
<p>There are many questions that remain unanswered, especially relating to hurdling technique, which has received much less scientific attention than <a href="https://theconversation.com/how-to-find-your-best-running-style-60398">that of sprinters</a>. For one thing, female hurdlers have to clear lower barriers so may not respond in the same way. Additionally, studies investigating how athletes change their technique as they progress from novice to national level to world class would be incredibly valuable to our understanding.</p><img src="https://counter.theconversation.com/content/120135/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Bezodis has previously received funding from Welsh Athletics and Sport Wales. </span></em></p><p class="fine-print"><em><span>Josh Walker and Matthew Wood do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Coaches have long thought hurdlers and sprinters start their races differently – our research suggests they need to adjust their thinking.Ian Bezodis, Senior Lecturer in Sports Biomechanics, Cardiff Metropolitan UniversityJosh Walker, PhD Candidate in Sports Biomechanics, Leeds Beckett UniversityMatthew Wood, Lecturer in Performance Sport, Cardiff Metropolitan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1164072019-05-06T10:37:45Z2019-05-06T10:37:45ZCaster Semenya’s impossible situation: Testosterone gets special scrutiny but doesn’t necessarily make her faster<figure><img src="https://images.theconversation.com/files/272560/original/file-20190503-103063-57i6mw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An arbitration court ruled that the 28-year-old runner must lower her testosterone levels in order to compete.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Czech-Republic-Athletics-Continental-Cup/a76d9a3a2be74b81bb27078e493a789a/27/0">AP Photo/Petr David Josek</a></span></figcaption></figure><p>A yearslong saga between a middle-distance runner and her sport’s ruling body may be nearing something that resembles a conclusion.</p>
<p>In 2018, the International Association of Athletics Federations <a href="https://www.iaaf.org/news/press-release/eligibility-regulations-for-female-classifica">dictated</a> that female runners with naturally occurring high testosterone levels and specific “<a href="https://www.ncbi.nlm.nih.gov/pubmed/24337131">differences of sex development</a>” must lower their testosterone in order to compete in events ranging from 400 meters to one mile.</p>
<p>Two-time Olympic champion Caster Semenya challenged the 2018 policy. It was discriminatory, <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">she argued</a>, lacked scientific grounding and did “irreparable harm to affected female athletes.”</p>
<p>But on May 1, in a blow to Semenya and an untold number of other women, the Court of Arbitration for Sport upheld the regulations. The policy is now set to go into effect <a href="https://www.iaaf.org/news/press-release/cas-female-eligibility-regulations">on May 8</a> </p>
<p>As a scholar who studies <a href="https://global.oup.com/academic/product/womens-sports-9780190657703?cc=us&lang=en&">women’s sports</a> I’ve been following this story closely. At the heart of the conflict is how to define “femaleness” for the purpose of athletic competitions. Since sports are segregated by sex, what criteria – if any – should we use to distinguish female from male? </p>
<h2>How we got here</h2>
<p>Monitoring testosterone is the latest version of “sex testing” in women’s sport, <a href="https://www.press.uillinois.edu/books/catalog/85fcr3nh9780252040221.html">a practice that began in the 1930s</a>. </p>
<p>Originally, athletes presented affidavits from their personal and team physicians confirming that they were, in fact, women. In the 1960s, athletic administrators turned to gynecological examinations, visual inspections and chromosomal analyses. In the 1990s, they implemented genetic testing.</p>
<p>By the 21st century, most systematic testing had been discontinued, <a href="https://www.doi.org/10.1080/00336297.2011.10483678">unless someone “challenged” a female athlete’s sex</a>. This happened to Semenya at the <a href="https://www.theguardian.com/sport/2009/aug/19/caster-semenya-800m-world-athletics-championships-gender">2009 Track and Field World Championships</a>. Someone apparently issued such a challenge and the press caught wind of it. The International Association of Athletics Federations confirmed that she was undergoing “gender verification” procedures, just before she cruised to victory in the 800-meter race. </p>
<p>Although her test results were never made public, the IAAF <a href="https://www.press.uillinois.edu/books/catalog/58ctr3rx9780252038167.html">subsequently issued a new policy</a> for women with hyperandrogenism, or high testosterone. Arguing that high testosterone gave these athletes an unfair advantage, hyperandrogenic female athletes had two choices: suppress their testosterone or drop out of the sport.</p>
<p>Indian sprinter <a href="https://www.iaaf.org/athletes/india/dutee-chand-275950">Dutee Chand</a> refused to do either. In 2014, the Sports Authority of India diagnosed her as hyperandrogenic and disqualified her from competition. Chand challenged that disqualification in the Court of Arbitration for Sport, <a href="https://www.tas-cas.org/fileadmin/user_upload/award_internet.pdf">where adjudicators ruled</a> the IAAF had “insufficient evidence” to enforce its policy. The decision gave the organization two years to find evidence that associated enhanced performance with naturally high levels of testosterone. If not, the policy would be invalidated.</p>
<p>As the 2017 deadline approached, researchers affiliated with the IAAF <a href="https://bjsm.bmj.com/content/51/17/1309">published a study</a> that claimed women with high testosterone performed as much as 3% better than those with lower testosterone in a handful of events. </p>
<p>Undeterred by <a href="https://doi.org/10.1007/s40318-019-00143-w">those who exposed the study’s methodological flaws</a>, <a href="https://theconversation.com/a-sexist-policy-may-end-the-career-of-one-of-the-commonwealths-greatest-female-runners-94390">the organization plowed ahead with its regulations</a>, prompting Semenya’s challenge. </p>
<h2>‘Necessary’ discrimination?</h2>
<p>Although it rejected Semenya’s claims, the Court of Arbitration for Sport’s panel <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">conceded</a> that the regulations are “discriminatory” but “necessary” to preserve “the integrity of female athletics.” The regulations are additionally discriminatory, panel members noted, because they “do not impose any equivalent restrictions on male athletes.” </p>
<p>This is something that critics of the policy <a href="https://www.theguardian.com/commentisfree/2018/apr/26/testosterone-ruling-women-athletes-caster-semanya-global-south">have charged from the beginning</a>.</p>
<p>No one is concerned about male athletes with unusually high, naturally occurring testosterone. Taking hormones out of the equation, there are a host of biological advantages that some athletes enjoy over others. Nordic skier Eero Mäntyranta, for example, had a <a href="https://www.penguinrandomhouse.com/books/309105/the-sports-gene-by-david-epstein/9781617230127/">genetic condition</a> that caused the excessive production of red blood cells, giving him an advantage in endurance events. Michael Phelps’ <a href="https://www.businessinsider.com/michael-phelps-rio-olympics-body-swimming-2016-8">unique and optimally shaped swimming body</a> allows him to cut through the water with remarkable speed and efficiency. No one suggests these men should muzzle their assets. </p>
<p>This is because we don’t divide sport into categories based on hemoglobin or foot size, regardless of the advantages each confers. </p>
<p>We do, however, carve sport into male and female categories, and for good reason. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761733/">Studies show</a> that elite male athletes tend to outperform elite female athletes by about 10%. Segregating men and women in most elite sports gives women more opportunities to compete and succeed.</p>
<p>Here’s where it gets tricky. If we insist on sexual segregation in sport, how do we decide who’s a female and who’s a male? Do those criteria influence sport performance? And what happens when athletes do not fit neatly into sport’s definition of femaleness?</p>
<p>This is precisely what the new regulations attempt to address, albeit in a clumsy and confounding way. Specifically, the policy is aimed at women who are legally recognized as women but who are diagnosed with specific differences of sex disorders and have high levels of functional testosterone. The IAAF explains that these disorders involve male-typical sex chromosomes and the presence of testes or testicular development. The threshold for women’s testosterone is below the “normal” male range but more than two times higher than the upper limit of the “normal” female range.</p>
<p>Semenya and her supporters argue that since the women affected by the policy are, in fact, women, they should be allowed to compete without restriction. </p>
<p>“I just want to run naturally, the way I was born,” <a href="https://www.telegraph.co.uk/athletics/2018/06/18/caster-semenya-files-legal-case-against-new-testosterone-rule/">she said</a>. “It is not fair that I am told I must change.”</p>
<p>It’s worth noting that although Semenya is the top athlete in her class, her times don’t come anywhere near the times of elite male runners – despite allegedly having “male levels” of testosterone.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Semenya blows away her female competitors, but her times wouldn’t allow her to compete against the top male runners.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Monaco-Athletics-Diamond-League/174e6fadd6e74e6e94dc77fd571091e1/32/0">AP Photo/Claude Paris</a></span>
</figcaption>
</figure>
<h2>Sporting rights versus human rights</h2>
<p>The controversy has divided activists for sporting rights and human rights. </p>
<p>The IAAF <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">regards women’s sport</a> as a “protected class” and insists that it must “place conditions” on the female category in order “to ensure fair and meaningful competition.”</p>
<p>Human rights activists disagree. If an athlete is legally a woman, that should be good enough. In fact, the United Nations Human Rights Council <a href="https://ilga.org/downloads/Elimination_of_discrimination_against_women_and_girls_in_sport.pdf">resolved</a> that the new regulations “may not be compatible with international human rights norms and standards.” <a href="https://www.sport24.co.za/OtherSport/Athletics/sas-sports-scientist-tucker-not-enough-evidence-to-curb-caster-20190502">Citing the assertions of esteemed scientists</a> and <a href="https://ewn.co.za/2019/02/21/testosterone-expert-karkazis-says-iaaf-has-no-evidence-to-back-its-claims">bioethicists</a>, the council criticized the “lack of legitimate and justifiable evidence for the regulations.” Put differently, there is no conclusive, incontrovertible correlation between high natural testosterone and better performance. Without such evidence, they argued, the IAAF’s regulations shouldn’t be enforced. </p>
<p>The Court of Arbitration panel members <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">did note</a> that they’re concerned about how the IAAF’s regulations will be practically applied. In addition, the IAAF regards the regulations as a “living document,” which means that it can and probably will change as time goes on. </p>
<p>Will the testosterone restrictions expand to additional track and field events? </p>
<p>Meanwhile, the International Olympic Committee <a href="https://www.cnn.com/2019/05/01/sport/caster-semenya-cas-hearing-spt-intl/index.html">is reportedly working on guidelines</a> to help international federations devise their own policies regarding “gender identity and sex characteristics.” In other words, we can expect to see policies similar to the IAAF’s in other sports.</p>
<p>Semenya has 30 days to appeal the arbitration ruling to the Swiss Federal Tribunal. If this appeal fails, she and countless other women must reduce their testosterone, probably with medication, to keep competing in women’s events. What will this do to their bodies? To the sport? To issues of fairness and human rights? </p>
<p>The Court of Arbitration decision is just one leg in what looks to be a never-ending and perhaps futile relay to establish “fairness” in women’s sports.</p><img src="https://counter.theconversation.com/content/116407/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaime Schultz does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Sports are segregated by sex. But what happens when athletes don’t fit neatly into sport’s definition of gender?Jaime Schultz, Associate Professor of Kinesiology, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1107612019-01-30T14:50:26Z2019-01-30T14:50:26ZNeanderthals were sprinters rather than distance runners, our study surprisingly suggests<figure><img src="https://images.theconversation.com/files/256379/original/file-20190130-108355-1m0tgg3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Neanderthals may not have been hunting in the tundra after all.</span> </figcaption></figure><p>The image of Neanderthals as brutish and culturally unsophisticated has <a href="https://theconversation.com/how-we-discovered-that-neanderthals-could-make-art-92127">changed in recent years</a> – they could make cave art, jewellery, complex stone tools and may have had language and cooked foods. Yes, they were extremely physically strong – certainly stronger than the vast majority of humans living today. And yes, they went extinct just after our own species entered their territories (albeit with a small amount of interbreeding). But neither fact means they were sluggish or cognitively inferior to us humans. </p>
<p>In our new study, <a href="https://www.researchgate.net/publication/329811193_Palaeoecological_and_genetic_evidence_for_Neanderthal_power_locomotion_as_an_adaptation_to_a_woodland_environment">published in Quaternary Science Reviews</a>, we now challenge another long-held view about our distant cousins: that they were pursuit hunters adapted to living in the cold tundra environments.</p>
<p>One reason why researchers think Neanderthals used to live in a cold climate is that their remains have been found next to <a href="https://www.researchgate.net/publication/232711218_Neanderthal_-_Modern_Human_Competition_A_Comparison_between_the_Mammals_Associated_with_Middle_and_Upper_Palaeolithic_Industries_in_Europe_during_OIS_3">those of ice age mammals</a> like mammoths, woolly rhinos, horses and reindeer. Some have also argued that their physical characteristics – particularly short limbs, large nasal cavity and a large torso – were evolutionary adaptations to living in the cold.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/256389/original/file-20190130-108351-1btg7w0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/256389/original/file-20190130-108351-1btg7w0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/256389/original/file-20190130-108351-1btg7w0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/256389/original/file-20190130-108351-1btg7w0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/256389/original/file-20190130-108351-1btg7w0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/256389/original/file-20190130-108351-1btg7w0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/256389/original/file-20190130-108351-1btg7w0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Neanderthal versus human.</span>
<span class="attribution"><span class="source">Nicolas Prim/Shutterstock</span></span>
</figcaption>
</figure>
<p>We wanted to see if this idea really held up – looking at both fossil and genetic evidence. We started by investigating when and where Neanderthals preferentially lived. We know this was in Europe and parts of Asia from around 300,000 years ago until around 40,000 years ago, when they started to go extinct. Sadly there are very few old Neanderthal fossils, so we know very little about their lives until about 130,000 years ago, just before the last ice age started. We therefore focused on their last occupation of north-west Europe, which was broadly a period during the Ice Age (60,000-20,000 years ago) when the climate <a href="https://www.clim-past.net/4/47/2008/cp-4-47-2008.pdf">fluctuated greatly</a>. </p>
<p>By investigating the sedimentary layers in which their fossils were found, we discovered animal remains such as rodents and certain other small mammals. Notably, these animals actually lived in the warmer episodes of the last ice age, when the environment was generally more wooded and less hospitable to mammoths.</p>
<p>So how come mammoths have previously been found at Neanderthal sites? We are still working out the details on this but it is possible that the ecology was such that mammoths may still have been able to live in this warmer climate. It is also possible that mammoths and Neanderthals were not in fact contemporary but their bones have subsequently been mixed together.</p>
<h2>Power versus endurance</h2>
<p>Hunting in woodland generally involves a need for speed and acceleration: in short, sprinting. This is because when you encounter prey, say behind trees, it can be very sudden and you need to respond rapidly. By contrast, the endurance running that characterises modern humans is more useful for pursuit hunting in open grassland environments or tundra. Our woodland theory led us to suggest that Neanderthals may have been adapted for sprinting rather than distance running.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/256184/original/file-20190129-108370-ijrwox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/256184/original/file-20190129-108370-ijrwox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/256184/original/file-20190129-108370-ijrwox.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/256184/original/file-20190129-108370-ijrwox.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/256184/original/file-20190129-108370-ijrwox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/256184/original/file-20190129-108370-ijrwox.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/256184/original/file-20190129-108370-ijrwox.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Skeleton and restoration model of Neanderthal.</span>
<span class="attribution"><span class="source">wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The idea that Neanderthals may have been built for speed gave us a new way of interpreting their body form. Among modern elite athletes, long distance runners tend to be lean and have long limbs, whereas short distance runners tend to be much more muscular and may have shorter limbs in proportion to their overall body size. It’s easy to see that the Neanderthal build is more like the sprinters than long distance runners.</p>
<h2>Genetic match</h2>
<p>To explore this idea further we looked at genetic variants <a href="https://www.ncbi.nlm.nih.gov/pubmed/27287076">previous studies had shown</a> to be associated with elite power or sprint athletes. We found that the majority of these power-associated genetic variants were in fact much more common in Neanderthals than in humans today. So it does seem that our theory derived from the study of Neanderthal ecology stands up to provisional genetic scrutiny.</p>
<p>It is important to note that these results are based on a relatively small number of Neanderthals whose DNA has been read. They are also based on the assumption that the genetic variants associated with power and speed in humans today act in the same or a similar way in Neanderthals. It is also possible that Neanderthals carried other genetic variants associated with locomotion – ones that are not present or have not been studied in living humans. As with all studies of the past, there are alternative explanations for the patterns we see, but the approach we have taken signposts a potentially valuable path for studying the evolution of the wider human family.</p>
<p>The emerging picture of how we differ from Neanderthals is no longer one of the smart versus the stupid, the sophisticated versus the unsophisticated, the brutish versus the refined, but instead one of jog versus sprint, of endurance versus speed. All species are uniquely adapted to the ecology they live in. It turns out that the differences once used to classify Neanderthals as more primitive than modern humans – such as their build – may instead simply reflect adaptations to different hunting requirements. Unfortunately for our Neanderthal cousins, and not for the last time, the tortoise beat the hare.</p><img src="https://counter.theconversation.com/content/110761/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Thomas receives funding from Wellcome, Leverhulme, and various research councils. </span></em></p><p class="fine-print"><em><span>John Stewart does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A new study suggests Neanderthals may have lived in woodlands rather than tundras, meaning they were most likely sprinters.John Stewart, Associate Professor of Evolutionary Palaeoecology, Bournemouth UniversityMark Thomas, Professor of Evolutionary Genetics, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1025132018-08-31T15:48:43Z2018-08-31T15:48:43ZCan Usain Bolt really make it as a footballer?<p>What to do when you’ve won it all?</p>
<p>After the 2017 World Championships and a truly stellar career, Usain St Leo Bolt bowed out of the sport he dominated for so long. Fame, fortune, and a personality to match, it’s hard to imagine Bolt was short of offers on hanging up his golden-laced spikes.</p>
<p>So, what do retired Olympic sprinters do: coach, commentate, agency work, celebrity TV appearances, or just rest on their laurels? Bolt had different ideas, openly expressing his desire to play professional soccer: “Maybe a club will see something and decide to give me a chance”, <a href="https://uk.reuters.com/article/uk-soccer-norway-bolt/sprinter-bolt-trains-at-norwegian-club-stromsgodset-idUKKCN1IV1DQ">he said</a>.</p>
<p>As an avid Manchester United fan, his most recent public appearance came as he captained the Rest of the World in the 2018 <a href="http://www.espn.co.uk/football/england/story/3522273/usain-bolt-nets-penalty-at-old-trafford-in-soccer-aid-charity-match">Soccer Aid</a> at Old Trafford. Prior to this, he trained with South African outfit Mamelodi Sundowns FC, Norway’s Stromsgodset, and even German giants <a href="https://www.facebook.com/BVB/videos/435825260197068/">Borussia Dortmund</a>. </p>
<p>In recent weeks, Bolt has earned an “indefinite training period” with Australian side Central Coast Mariners, and on August 31 he <a href="https://twitter.com/CCMariners/status/1035485893929271296">made his debut</a> as a “trialist” in a pre-season friendly against amateur side Central Coast Football. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1035485893929271296"}"></div></p>
<p>Notwithstanding Bolt’s profile, such sporting career transitions raise a series of questions for scientists like me with an interest in expertise research, and elite performance. How do individuals achieve such expertise? Is it possible to transfer between sports? And are some sports easier to transfer to than others?</p>
<h2>What is ‘expertise’?</h2>
<p>Expertise can be defined as the ability of an person to <a href="https://www.sciencedirect.com/science/article/pii/S0166411508614624">consistently demonstrate superior levels of proficiency</a> within a particular domain over an extended period of time. This is highlighted perfectly by Bolt, who won gold in the 100m, 200m, and 4x100m relay at three successive Olympics.</p>
<p>Historically, theorists studying expertise have fallen into <a href="http://psycnet.apa.org/record/1996-98355-001">two schools of thought</a> that parallel the “nature versus nurture” debate. Some, such as the 19th-century scientist Francis Galton, argued that eminence in science, music, art, and other fields reflects an <a href="http://psycnet.apa.org/record/1996-98355-001">innate or natural ability</a>.</p>
<p>But practice is uniformly regarded as the single variable that has the <a href="https://www.researchgate.net/publication/224827585_The_Role_of_Deliberate_Practice_in_the_Acquisition_of_Expert_Performance">greatest influence on skill acquisition</a>. And this lead to the alternative viewpoint that it takes a minimum of 10,000 hours or ten years of “deliberate practice” to achieve domain-specific expertise.</p>
<p>Typically, researchers today are of the view that while the sheer amount of practice is important, other factors, such as genetics, ability and motivation are <a href="http://psycnet.apa.org/record/1999-11726-001">also likely to be critical</a>. To this end, though Bolt may be blessed with certain hereditary capabilities such as height and a greater proportion of fast-twitch muscle fibres, he has also invested the necessary training hours in order to reach the top of his sport. </p>
<h2>Soccer expertise</h2>
<p>So how easy is it to become a footballer? Soccer expertise is multi-faceted in nature, compromising of <a href="https://www.researchgate.net/publication/294217815_Talent_identification_in_soccer">physiological, emotional, technical, and cognitive factors</a>. By looking at how much footballers have practiced in the past, sports scientists have attempted to shed light on how they developed those skills.</p>
<p>In their study of elite English soccer players, one group of researchers concluded that <a href="https://www.researchgate.net/publication/255653625_DELIBERATE_PRACTICE_AND_EXPERT_PERFORMANCE_DEFINING_THE_PATH_TO_EXCELLENCE">early specialisation</a> is an important precursor to expertise. Specifically, players would engage in deliberate practice of their primary sport – in this case, football – from a young age (around five years). These activities are <a href="https://www.routledge.com/Science-and-Soccer-Developing-Elite-Performers/Williams/p/book/9780415672115">highly structured and often coach-led</a>, with the specific purpose of improving performance.</p>
<p>The <a href="https://www.tandfonline.com/doi/abs/10.1080/02640414.2012.701762?src=recsys&journalCode=rjsp20">early engagement</a> pathway is an alternative approach, which involves meaningful amounts of unstructured soccer-playing during childhood (six to 12 years of age), rather than coach-led practice and competition (“deliberate practice”).</p>
<p>Anecdotal evidence exists of Bolt playing street <a href="https://www.theguardian.com/sport/2012/jun/17/usain-bolt-this-much-i-know">cricket and soccer</a> when growing up, which seems to fit more with the early engagement pathway. That said, without a detailed account of his practice history it is impossible to know how his sporting childhood may have shaped his soccer potential.</p>
<h2>Transfer between sports</h2>
<p>In light of his athletic commitments, it is difficult to see how Bolt has accumulated the required practice hours, in either soccer play or deliberate practice, to successfully transition to the professional game.</p>
<p>This brings us onto the question as to whether the skills developed from his years of experience in sprinting, could transfer to soccer. We know that successful career transitions are possible and one example is the former track cyclist Victoria Pendleton: after retiring from the velodrome at age 31 with Olympic and world titles, she made her competitive debut in <a href="https://www.bbc.co.uk/sport/horse-racing/34122804">horse racing</a> three years later.</p>
<p>How successful the transfer can be depends on the level of <a href="http://psycnet.apa.org/buy/1926-02960-001">identical or similar elements</a> that exist between the two performance domains. Sports scientists have classified these elements into <a href="https://scholar.google.co.uk/scholar?q=Shifting+training+requirements+during+athlete+development&hl=en&as_sdt=0&as_vis=1&oi=scholart">four categories</a>:</p>
<ul>
<li><p>Physical conditioning: general physiological changes shared between similar modes of activity.</p></li>
<li><p>Movement: the anatomical and biomechanical similarities between tasks.</p></li>
<li><p>Perceptual: the environmental information used to make performance related decisions.</p></li>
<li><p>Conceptual: similarities in the strategies, rules and guidelines governing behaviour during competition.</p></li>
</ul>
<p>With the exception of certain aspects of physical conditioning such as reaction speed, and perhaps movements such as acceleration, it is evident that track sprinting and soccer share very little in common.</p>
<p>In contrast, it could be argued that many more similarities exist between sprint cycling and horse racing (pacing strategies, for instance), hence Pendelton’s successful transition.</p>
<p>Although only a very brief overview of expertise and the issue of transfer, the odds are stacked against Bolt, not least because he is 32 and soccer players typically reach their peak <a href="https://www.bbc.co.uk/news/magazine-28254123">a few years earlier</a>.</p>
<p>That said, transfer from one sport to another is a complex process and all sorts of physical, social or functional variables can influence the <a href="https://rapunselshair.pbworks.com/f/barnett_2002.pdf">rate and degree of transfer</a>. </p>
<p>Be it fate, genetics, or sheer persistence, sometimes, everything just works out. A prime example comes from this year’s Tour de France. While most racers had devoted their lives to cycling – overall winner Geraint Thomas began aged ten – fourth place Primož Roglič was a <a href="https://www.washingtonpost.com/news/early-lead/wp/2017/07/19/a-former-ski-jumper-who-only-took-up-cycling-in-2012-won-stage-17-of-the-tour-de-france/">former junior world ski jumping champion</a>. His achievement was even more astonishing given he only took up cycling in 2012, already in his 20s.</p><img src="https://counter.theconversation.com/content/102513/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edward Hope does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Sports science suggests not.Edward Hope, Lecturer, School of Sport, Rehabilitation and Exercise Sciences, University of EssexLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/985122018-06-25T14:19:18Z2018-06-25T14:19:18ZHigh-intensity training: why adjusting recovery periods could boost your fitness<figure><img src="https://images.theconversation.com/files/223778/original/file-20180619-126534-17wcf8i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Stoppage time. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sports-man-resting-after-run-while-313498589?src=yNtUvTkmKpzGf7cnfu_9-Q-1-20">GaudiLab</a></span></figcaption></figure><p>From World Cup footballers to amateur enthusiasts, <a href="https://www.self.com/story/what-is-high-intensity-interval-training-benefits">high-intensity interval training</a> has become a staple of fitness regimes worldwide. It is about exercising for short, intense periods, interspersed with brief intervals for recovery. </p>
<p>People who take part are usually free to work as hard as their fitness levels and motivation will allow, though the length of the recovery period tends to be predefined. The logic is that this ensures an appropriate work-to-rest ratio – the more intensely you want to work the more recovery should be allowed. </p>
<p>For example, if someone is trying to improve their <a href="http://speedendurance.com">speed endurance</a> – the ability to maintain running speed over multiple repetitions with limited recovery – they need to run as fast as possible, necessitating recovery periods <a href="https://journals.lww.com/nsca-jscr/Fulltext/2011/09000/The_Effect_of_40_m_Repeated_Sprint_Training_on.3.aspx">upwards of</a> five times the length of the exercise bout. To improve aerobic fitness, on the other hand, it is <a href="https://www.tandfonline.com/doi/abs/10.1080/24733938.2018.1461235">likely that</a> recovery will be equal to or slightly less than the exercise period.</p>
<p>But what about creating a training regime that takes account of the individual? Researchers have become interested in individualising the intensity of an exercise programme. They <a href="https://shapeamerica.tandfonline.com/doi/abs/10.1080/02640414.2013.792953#.Wyje7hiZORs">have shown</a>, for example, that if people run at speeds tailored to their fitness levels it is more beneficial than if everyone did the same. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/223785/original/file-20180619-126559-1hdzdxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/223785/original/file-20180619-126559-1hdzdxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/223785/original/file-20180619-126559-1hdzdxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/223785/original/file-20180619-126559-1hdzdxy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/223785/original/file-20180619-126559-1hdzdxy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/223785/original/file-20180619-126559-1hdzdxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/223785/original/file-20180619-126559-1hdzdxy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/223785/original/file-20180619-126559-1hdzdxy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lift-off!</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sprinter-leaving-on-running-track-explosive-366018920?src=fwP_hfKIuwFigD9n3EGsGw-1-9">Jesus Cervantes</a></span>
</figcaption>
</figure>
<p>Yet few studies have considered tailoring the length of the recovery periods. We <a href="https://link.springer.com/article/10.2165/00007256-200131010-00001">know that</a> the speed at which people recover from bouts of high-intensity exercise is at least partly affected by their aerobic fitness – so why don’t we individualise recovery duration in training programmes, for example, by allowing people to decide how long they rest for?</p>
<h2>Self-selection</h2>
<p>Repeated sprinting is a popular method of high-intensity training in which recovery periods tend to be predefined irrespective of the individual’s age or fitness. I have been involved in several studies that have experimented with letting youngsters take a different approach. </p>
<p>In <a href="https://journals.humankinetics.com/doi/abs/10.1123/pes.2016-0130">the first</a> study, 11 young athletes aged 13 performed six 30 metre sprints on two occasions. Trials were separated by six days and the athletes alternately used standardised and self-selected recovery periods to intersperse their sprints. For those doing the standardised trial, sprints started every 30 seconds, meaning around 26 seconds of recovery for each person. In the self-selected recovery trial, the athletes were asked to allow enough time so ensure they could sprint as fast as possible in each repetition. </p>
<p>You might assume that people know how much recovery time this takes. In fact, the athletes’ performances actually declined when they were allowed to choose their recovery periods. So far so bad – self-selected recovery didn’t improve performance. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/223787/original/file-20180619-126566-1iibj25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/223787/original/file-20180619-126566-1iibj25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/223787/original/file-20180619-126566-1iibj25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/223787/original/file-20180619-126566-1iibj25.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/223787/original/file-20180619-126566-1iibj25.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/223787/original/file-20180619-126566-1iibj25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/223787/original/file-20180619-126566-1iibj25.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/223787/original/file-20180619-126566-1iibj25.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lining up.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sprinter-leaving-on-running-track-explosive-366018920?src=fwP_hfKIuwFigD9n3EGsGw-1-9">Sergey Novikov</a></span>
</figcaption>
</figure>
<p>There were however some positives. While running the self-selected recovery trial, the athletes had higher heart rates and a greater accumulation of blood lactate – both of which <a href="http://www.henriquetateixeira.com.br/up_artigo/aerobic_endurance_training_improves_soccer_performance_va5te8.pdf">can be beneficial</a> when the aim of the training is to improve aerobic fitness.</p>
<p>Two of the athletes actually did improve their performance when choosing their own recovery periods, recording faster sprints and maintaining higher average running times overall. So, at least for some, set recovery periods may prevent them from working as hard as they would like. It suggests that coaches working with youngsters should be willing to experiment to see which method works better. </p>
<h2>Maturity and age</h2>
<p>More recently we have been looking at how recovery choices are affected by age and maturity. In a study soon to be published in Pedeatric Exercise Science, we asked 28 young athletes to perform ten 30-metre sprints on two occasions, separated by one week, again sprinting as fast as possible and using a different recovery method for each trial. We divided the athletes into a more mature and less mature group, depending on whether they had experienced the adolescent growth spurt.</p>
<p>When using standardised 30-second recovery periods, the less mature group’s sprint times declined to a lesser degree across the test compared to the more mature group. When allowed to self-select, however, it was the more mature group that maintained sprint speed to a greater degree. </p>
<p>This was likely the result of the less mature group choosing to recover more quickly, averaging around 160 seconds compared to around 190 seconds in the more mature group. Importantly, however, both groups chose less time to recover than what was allocated in the standardised trial, 270 seconds. This meant that both groups performed better using standardised recovery. </p>
<p>In another recent study <a href="https://www.tandfonline.com/eprint/fZNrFC5jnj7BqRRrzaHy/full">we also looked at adults</a>. We asked 14 amateur athletes aged 30 to run a dozen times for 30 seconds on a non-motorised treadmill on two occasions, again separated by one week, interspersing runs with either 30 seconds of recovery or their a period of their choosing. Unlike the previous two studies above, these athletes were asked to run at speeds individualised to their <a href="https://www.protrainingprograms.com/blog/determining-your-maximum-aerobic-speed">aerobic fitness</a>. </p>
<p>This time, the athletes rested for longer when they were choosing their recovery times than when they were pre-determined. Self-selection also enabled them to spend more time at or above their target speed. This suggests that combining prescribed running speeds and self-selected recovery periods may benefit athletes “tapering” their training as they approach a competition – in this case by running faster while minimising fatigue through longer recovery periods.</p>
<p>And while the results are not directly comparable with the other two studies – the adults ran at prescribed running speeds whereas the children were running as fast as possible – it does look as though adults are better than children at choosing recovery times that allow them to maintain <a href="https://journals.lww.com/nsca-jscr/Fulltext/2014/12000/Overestimation_of_Required_Recovery_Time_During.9.aspx">performance</a>. Whether this is the result of age, maturity or experience of high intensity training is unclear.</p>
<p>At any rate, our studies show that choosing your own recovery duration can be beneficial in certain circumstances. Next we are looking at whether training programmes lasting two to six weeks and using self-selected recovery periods result in positive changes in fitness. It would also be interesting to see if this approach made people more willing to stick to an exercise regime. If it did, that would be good news for <a href="https://theconversation.com/health-check-high-intensity-micro-workouts-vs-traditional-regimes-18617">those who</a> find prescriptive regimes difficult to stick to.</p><img src="https://counter.theconversation.com/content/98512/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Neil Gibson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Most people follow fixed time periods when it comes to recovery. The latest research calls this into question.Neil Gibson, Director of Sport, Performance and Health, Heriot-Watt UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/822122017-08-10T20:06:46Z2017-08-10T20:06:46ZIs Usain Bolt the greatest athlete of all time? That’s not what the numbers say<p>Usain Bolt has finally hung up his running shoes, retiring from athletics amid plaudits hailing him as the <a href="http://www.news.com.au/sport/more-sports/world-athletics-championships-twice-banned-justin-gatlin-makes-sure-usain-bolt-has-no-fairytale-ending/news-story/e90514a60f1f5de0c429fd51ce4d7db3">greatest athlete</a> and <a href="https://www.theguardian.com/sport/2017/aug/05/bolts-time-runs-out-greatest-athletics-champion-of-them-all">greatest champion</a> of all time.</p>
<p>While it wasn’t quite the fairy tale ending in <a href="http://www.news.com.au/sport/more-sports/usain-bolt-runs-his-final-ever-100m-final/news-story/2b2f8df4ebefb0aed1b0538c369b150c">Bolt’s final race</a> – he came third and claimed only bronze in the 100m final at the IAAF World Athletics Championships in London – his overall career results are certainly fit for the record books.</p>
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<figcaption><span class="caption">The final sprint race for Usain Bolt saw him bring in the bronze.</span></figcaption>
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<p>He is the fastest runner in history over 100m and 200m, as well as winning the “<a href="http://www.abc.net.au/news/2016-08-20/rio-2016-usain-bolt-claims-triple-triple-at-olympics/7769198">triple triple</a>” at the Olympics: gold in the 100m, 200m and 4x100m relay at three consecutive games, in Beijing, London and Rio. (The Beijing 2008 4x100m relay gold <a href="https://www.theguardian.com/sport/2017/jan/25/usain-bolt-jamaica-olympic-relay-gold-nesta-carter-drugs">was later revoked</a> after his team mate Nesta Carter was disqualified for failing a drug test.)</p>
<p>Bolt also held the world championship title over these distances between 2009 and 2015, with the exception of <a href="http://www.bbc.com/sport/athletics/14698558">one false start in the 100m</a> in 2011. </p>
<p>But is the Jamaican athlete the greatest of all time, as is <a href="http://www.news.com.au/sport/olympics/we-name-the-greatest-athletes-of-all-time-in-the-wake-of-usain-bolts-remarkable-feats-at-rio-olympics/news-story/65b3f82a2e13c88d14a3104929419df3">often claimed</a>? </p>
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Read more:
<a href="https://theconversation.com/the-secret-to-usain-bolts-speed-may-lie-in-synchronicity-37897">The secret to Usain Bolt's speed may lie in synchronicity</a>
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<h2>How to compare athletes</h2>
<p>This is an interesting question given how the athletics world has changed over time. </p>
<p>Athletes today have access to cutting-edge training methods, nutrition plans and <a href="https://www.clearinghouseforsport.gov.au/knowledge_base/organised_sport/sports_and_sports_organisations/sport_technology">scientific and technological advancements</a> in equipment such as <a href="http://www.bbc.com/news/science-environment-18735617">track composition</a> and <a href="http://www.popularmechanics.com/adventure/sports/g1101/the-evolution-of-athletic-shoe-tech/">footwear</a>. There have also been improvements in measuring an <a href="https://www.sporttechie.com/track-and-field-technology-is-rapidly-advancing/">athlete’s performance during a race</a>. </p>
<p>The performance of past 100m winners could be influenced by a number of things such as race conditions and scientific advantages that were available at the time.</p>
<p>For Bolt to truly deserve the title of “greatest of all time”, we need to compare his results to those of previous athletes over the 100m. We also need to compare his track performances to the fastest times over the other track distances. We can do this <a href="https://doi.org/10.1515/jqas-2012-0047">using statistics</a>.</p>
<p>If we look at the fastest 100m race times for each year, we see there has been a large decrease in fastest times for both men and women. </p>
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<p>This pattern of decreasing times is observed for race times across all distances. A key reason in the decrease in race times is due to advances in modern training and scientific knowledge. In our statistical model, we include a changing trend in time so we can compare athlete performances in different years. </p>
<p>We also need to include adjustments in our statistical model for environmental and political factors that influence the population from which athletes are. During World War I and World War II, for example, the pool of athletes was depleted by men away fighting for their country.</p>
<p>The statistical model that we used, that includes both the trend in time and adjustment for population influences, is called a <a href="https://www.encyclopediaofmath.org/index.php/Weibull_distribution">Weibull distribution</a>.</p>
<p>This distribution is perfect for calculating the probability of rare events occurring in a given year, such as the fastest race times, and is ideal for estimating the probability of breaking world records.</p>
<h2>Crunch the numbers</h2>
<p>We use this distribution to model the fastest race times each year over the distances 100m, 200m, 400m, 800m, 1500m, 5000m and 10,000m. Using the statistical properties of the distribution, we can then rescale to compare different athletes’ performances over different distances. This means we can answer the question: is Usain Bolt the greatest athlete of all time?</p>
<p>The top 10 rankings from the statistical model are given below. These rankings account for the advantage of racing in different years and account for performances over different distances. </p>
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<p>Bolt is the world’s fastest man of all time over 100m and 200m but the title of world’s greatest athlete goes to <a href="https://www.biography.com/people/lee-evans-38545">Lee Evans</a> of the United States, who broke the world record in the <a href="https://www.olympic.org/lee-evans">mens 400m at the Olympics in 1968</a> in Mexico City.</p>
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<figcaption><span class="caption">Lee Evans wins the race and a new world record.</span></figcaption>
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<p>For women, the greatest athlete of all time is <a href="https://www.biography.com/people/florence-joyner-9542053">Florence Griffith-Joyner</a> of the United States for her performance in the <a href="https://www.theguardian.com/sport/london-2012-olympics-blog/2012/apr/11/olympic-florence-griffith-joyner-seoul">100m in the US Olympic Trials in 1988</a>. Her records for both 100m and 200m remain unbroken today.</p>
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<p>Griffith-Joyner’s 100m world record time of 10.49s was suspected to be wind-assisted. But she also ran the second- and third-fastest official times in history for the women’s 100m, at 10.61s and 10.62s, so the title is well deserved.</p>
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<figcaption><span class="caption">Florence Griffith-Joyner, also known as ‘Flo Jo’</span></figcaption>
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<h2>The study of extremes</h2>
<p>All this number crunching might seem like just a bit of fun, but statistical modelling of minima and maxima is actually really important and commonly used in fields of engineering, finance and earth sciences.</p>
<p>For example, we use distributions like this one to model the wettest day of the year and estimate the amount of rainfall we expect on average once every 100 years – the 1-in-100-year prediction.</p>
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Read more:
<a href="https://theconversation.com/explainer-was-the-sydney-storm-once-in-a-century-40824">Explainer: was the Sydney storm 'once-in-a-century'?</a>
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<p>This allows us to build infrastructure to cope with extreme rainfall events, like drainage and levee banks, and protect against rainfall events that we may not have even seen yet.</p>
<p>But the statistical modelling also gives us a useful method of checking to see if claims of athletic greatness or champion uphold to scrutiny of the numbers.</p><img src="https://counter.theconversation.com/content/82212/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kate R Saunders receives scholarship funding from the ARC through the Laureate Fellowship FL130100039, top funding from CSIRO and is a student with the Australian Centre of Excellence in Mathematical and Statistical Frontiers (ACEMS).</span></em></p><p class="fine-print"><em><span>Alec G Stephenson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Jamaican Usain Bolt is often hailed as the greatest athlete of all time. But when you crunch the numbers, his name doesn’t come top of the list.Kate R Saunders, PhD Student, The University of MelbourneAlec G Stephenson, Senior Data Scientist, Data61Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/640742016-08-19T21:29:25Z2016-08-19T21:29:25ZWhat food does it take to fuel athletes like Usain Bolt to Olympic success?<p>Usain Bolt <a href="http://www.bbc.co.uk/sport/olympics/36690965">made history</a> at the Rio Olympics, becoming the first athlete to win gold in the 100 metre and 200 metre sprints at three consecutive games. He <a href="http://www.independent.co.uk/sport/olympics/rio-2016-usain-bolt-angry-world-record-200m-gold-medal-a7198746.html">didn’t beat his world record</a> of 9.58 seconds, but still managed to leave his competitors for dust. </p>
<p>It takes years of intense training and enormous discipline for athletes such as Bolt to achieve their Olympic dreams – and throughout it all they have to adhere to strict dietary requirements. To find out what sort of food it takes to fuel Bolt’s Olympic efforts, it’s worth taking a closer look at an Olympic sprinter’s ideal diet.</p>
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<p>In the run up to the Olympic Games, Bolt would actually require more energy than during the games themselves. High quality preparatory training sessions use up a huge number of calories which need to be replaced with the correct nutrients. After all, these sessions are crucial in giving Bolt the all-important muscle power and technique that help him to gain the advantage over his competitors.</p>
<h2>Protein over carbo-loading</h2>
<p>During training, sprinters have to maintain a nourishing and balanced diet. This is predicated on the familiar mix of protein, carbohydrate, vitamins and minerals. Unlike some endurance athletes, sprinters don’t need to <a href="https://theconversation.com/carbo-loading-for-sport-is-simple-when-you-know-how-8071">carbo-load</a> with bread, potatoes, rice, pasta and cereals. Instead, protein – found in eggs, meat, fish, nuts, beans and dairy products – is perhaps the key dietary requirement. Protein allows muscles to recover, repair and develop after sprint and resistance drills which cause minute damages to the muscle fibres. </p>
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<img alt="" src="https://images.theconversation.com/files/134765/original/image-20160819-30377-x9kvyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/134765/original/image-20160819-30377-x9kvyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=372&fit=crop&dpr=1 600w, https://images.theconversation.com/files/134765/original/image-20160819-30377-x9kvyu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=372&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/134765/original/image-20160819-30377-x9kvyu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=372&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/134765/original/image-20160819-30377-x9kvyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/134765/original/image-20160819-30377-x9kvyu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/134765/original/image-20160819-30377-x9kvyu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Another piece of chicken?</span>
<span class="attribution"><span class="source">Elena Schweitzer/Shuttertock</span></span>
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<p>Carbohydrates are still crucial for sprinters as sprint training also uses up a huge amount of a compound called glycogen. When we eat carbohydrate, it is broken down and stored by the body in the muscles and liver <a href="https://www.sciencedaily.com/terms/glycogen.htm">in the form of glycogen</a>. Sprint training can deplete glycogen stores very quickly since it’s the only fuel available to the body at such high intensity effort. Bolt’s 100 metre world record time of 9.58 seconds isn’t long enough for the body to process the oxygen it needs and so energy is provided anaerobically – without oxygen – from fuels already found in the muscles.</p>
<p>The all out effort of sprinting can use up most, if not all, of the glycogen stored in the body. During a training session, if Bolt is doing repeated sprints of 20 to 50 metres, the majority of his muscles’ glycogen <a href="http://www.faqs.org/sports-science/Fo-Ha/Glycogen-Depletion.html">will be depleted</a> after about eight to ten efforts. Good nutrition is therefore vital to restock the lost glycogen and repair any routine muscular damage that’s been done.</p>
<p>When the Olympic Games draws closer – and with the bulk of athletes’ training behind them – their energy requirements lessen and they look to simply maintain their weight. The good news for sprinters is that there’s a reasonable amount of flexibility with what they can eat the night before a medal race. Apart from adhering to the basic principals of a balanced diet, the main recommendations are to limit fibre intake and to avoid a high-fat meal – which can lie heavily in the stomach. Athletes should also stick to familiar dishes to avoid upsetting their digestion with food that they’re not used to the night before a race. Trying local delicacies is best left until after the games have finished. </p>
<p>Rest assured, however, that there is some wriggle room, even in the diet of a world class sprinter. If Bolt’s <a href="http://www.independent.co.uk/sport/general/athletics/usain-bolt-reveals-he-devoured-1000-chicken-mcnuggets-during-the-2008-beijing-olympics-8920870.html">fabled love of chicken nuggets</a> is indeed true, then he wouldn’t have to constantly deprive himself of his favourite snack. Although eating fried food every day would cause an excess of fat in the diet, the energy demands on athletes are so high during full training that they can get away with more sweet treats and slightly more fat than the average person. So Bolt can afford to indulge as an occasional luxury, and if he’s just won a gold medal, he certainly deserves it. </p>
<p>And although sprinters are recommended to have a slightly higher protein intake for repair and growth than the general population, Bolt’s diet is not fundamentally different to what an average person should be ideally looking to eat, except of course energy requirements would be higher. Most people should eat a well balanced mix of carbohydrates: pasta, bread, cereals and potatoes, and protein foods: meat, fish, cheese, egg and milk, beans and pulses as well as plenty of vitamin loaded fruit and vegetables. And there’s even room for the occasional indulgence, although the rest of us might not have quite as good an excuse as Bolt for a high-fat binge. </p>
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<p><em>This article was based on a segment from episode four of <a href="https://theconversation.com/uk/podcasts/the-anthill">The Anthill</a>, a podcast from The Conversation on the subject of fuel. <a href="https://theconversation.com/anthill-4-fuel-64021">Click here</a> to listen to the full episode.</em></p><img src="https://counter.theconversation.com/content/64074/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emma Kinrade does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>No carb-loading necessary …Emma Kinrade, Lecturer in Dietetics, Glasgow Caledonian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/629762016-08-15T07:12:23Z2016-08-15T07:12:23ZWhat makes a winning sprinter?<p>In all sprint running races (100m to 400m), every hundredth of a second gained or lost in the race counts. But, most importantly, the fastest male and female sprinters attain incredible top running speeds, <a href="https://www.youtube.com/watch?v=SyY7RgNLCUk">with peaks in excess of 44km per hour</a> and 38km per hour in the men’s and women’s 100m races, for example. So what makes a fast runner?</p>
<p>The fastest sprinters on average take longer strides than slower sprinters, but at a <a href="http://www.ncbi.nlm.nih.gov/pubmed/1615256">similar stride rate</a>. This results from larger forces being delivered to the ground in the short foot-ground contact period (often 0.1 second). </p>
<p>Of course, having longer legs can <a href="http://www.ncbi.nlm.nih.gov/pubmed/23717364">benefit stride length</a>, which appears to be a significant <a href="http://www.meathathletics.ie/devathletes/pdf/Biomechanics%20of%20Sprints.pdf">reason for Usain Bolt’s superior top speed</a>. </p>
<h2>Generating force</h2>
<p>In addition to improving stride length, the greater distance of the foot from the hip in taller sprinters allows a faster backwards horizontal foot speed to be attained for a given hip angular velocity, since the foot velocity (v) is a function of hip angular velocity (ω) and hip-foot distance (r); v = ωr.</p>
<p>But it’s not all good news for taller runners. Longer limbs have a greater moment of inertia (they’re harder to move), so they’re accelerated less for a given hip torque production (i.e. muscle force). </p>
<p>In this case, there are different costs-benefits for shorter versus taller sprinters; shorter sprinters must attain faster limb movement speeds, but taller sprinters need to generate sufficient torque to rapidly accelerate their longer limbs.</p>
<p>It’s also clear that rapid force production is paramount. Peak <a href="http://www.ncbi.nlm.nih.gov/pubmed/18317373">forces of more than 2500N</a> (255kg) are delivered to the ground within a few hundredths of a second in each step.</p>
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<a href="https://images.theconversation.com/files/132751/original/image-20160802-17165-1qrd3py.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/132751/original/image-20160802-17165-1qrd3py.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/132751/original/image-20160802-17165-1qrd3py.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/132751/original/image-20160802-17165-1qrd3py.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/132751/original/image-20160802-17165-1qrd3py.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/132751/original/image-20160802-17165-1qrd3py.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/132751/original/image-20160802-17165-1qrd3py.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/132751/original/image-20160802-17165-1qrd3py.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Ground forces during sprint running. Faster sprinters (black line) produce greater forces in a shorter time (often <0.1s) than slower sprinters (grey line). The ability to produce large forces rapidly against the ground is a key to successful sprinting.</span>
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<p>If we continued to produce such rates of force for just one second, we could accelerate a Forumula 1 car to 100km per hour, or an 80kg athlete to about 900km per hour. Of course, peak force potential is limited in humans, so we won’t see this in Rio.</p>
<h2>Muscular design</h2>
<p>To deliver such forces, we might expect that sprinters possess a unique muscular design, and there is some evidence for this. Better sprinters have a <a href="http://www.ncbi.nlm.nih.gov/pubmed/129449">high proportion of type II muscle fibres</a>, which can develop forces so rapidly that they’re commonly called “fast twitch” fibres. </p>
<p>Further, some important power-producing muscles in their calf and thigh regions may possess <a href="http://www.ncbi.nlm.nih.gov/pubmed/10710372">longer muscle fibre bundles</a> (which is thought to contribute to faster muscle-shortening speeds) attaching at <a href="http://www.ncbi.nlm.nih.gov/pubmed/10710372">smaller angles to the tendon</a> than slower runners.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/133617/original/image-20160810-18014-1jo9xuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/133617/original/image-20160810-18014-1jo9xuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/133617/original/image-20160810-18014-1jo9xuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/133617/original/image-20160810-18014-1jo9xuz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/133617/original/image-20160810-18014-1jo9xuz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/133617/original/image-20160810-18014-1jo9xuz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/133617/original/image-20160810-18014-1jo9xuz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/133617/original/image-20160810-18014-1jo9xuz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In this ultrasound image of the vastus lateralis, a lateral thigh muscle, the muscle fibre bundles can be seen to run at an angle (dotted line denotes the fibre direction at one part of the muscle) to the muscle’s shortening direction (arrow). Sprinters tend to have longer fibres that attach, in this muscle at least, at smaller angles to the muscle-shortening direction. This is believed to improve the high-speed shortening of the muscle.</span>
</figcaption>
</figure>
<p>But, perhaps paradoxically, the best sprinters don’t have super-sized muscles.</p>
<p>One reason is that even the fastest muscles produce forces too slowly to allow humans to come close to the fast running speeds required, and increasing their size doesn’t help them produce forces any faster.</p>
<p>Instead, muscular forces stretch elastic tissues, such as tendons, and stored energy is subsequently recaptured at much faster rates when they recoil. Because of this, tendons work as “<a href="http://www.ncbi.nlm.nih.gov/pubmed/21228194">power amplifiers</a>”. </p>
<p>However, we know little about the effect of changing tendon properties. We do know that sprint runners have <a href="http://www.ncbi.nlm.nih.gov/pubmed/17101142">stiffer Achilles tendons</a> than non-runners. This should allow them to cope better with forces of over <a href="http://www.ncbi.nlm.nih.gov/pubmed/1638639">900kg placed on the tendon</a> and to recoil faster while under load during the propulsion phase of the foot-contact phase. </p>
<p>We also know that exercise such as <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4535734/">strength training tends to increase</a> their stiffness while detraining reduces it. </p>
<p>But we don’t yet know what the optimum stiffness is for the Achilles tendon (or other tendons), and we can’t yet set training programs to optimise them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/132754/original/image-20160802-17198-1gc8hrv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/132754/original/image-20160802-17198-1gc8hrv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/132754/original/image-20160802-17198-1gc8hrv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/132754/original/image-20160802-17198-1gc8hrv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/132754/original/image-20160802-17198-1gc8hrv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/132754/original/image-20160802-17198-1gc8hrv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/132754/original/image-20160802-17198-1gc8hrv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/132754/original/image-20160802-17198-1gc8hrv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Before foot-ground contact (left panel) the muscle (pink) and tendon (spring) are relatively inactive. During ground contact, the joints are flexed and muscles highly active (red). Tendons and other elastic structures are stretched and store energy. As the leg extends behind the athlete during propulsion (right panel), muscle shortening is accompanied by tendon recoil, allowing for high rates of force production.</span>
</figcaption>
</figure>
<h2>Getting a move on</h2>
<p>Another issue is that increased muscle mass increases limb inertia (in much the same way as greater limb lengths do), so reducing the acceleration for a given joint torque production. </p>
<p>The best sprinters therefore have very low limb masses, which enables them to cyclically move their arms and legs at high speeds. So, the <a href="http://www.ncbi.nlm.nih.gov/pubmed/21916672">leanest sprinters may be the fastest</a>.</p>
<p>Of final note is that sprinters must deliver their large forces to the ground in a <a href="http://www.ncbi.nlm.nih.gov/pubmed/22422028">very specific direction</a> and with the least wasted energy. They spend years learning techniques that minimise unnecessary limb movements, particularly those in the frontal and transverse planes (those that are not in the direction of running). </p>
<p>The sprinters at the front in the finals will surely display better running techniques.</p>
<p>So while you might not be able to pick the fastest sprinters through muscle fibre type, fibre bundle length, or tendon stiffness tests, you can be sure their limb masses will be small and their techniques will be the most efficient. And after the races are over, perhaps we’ll be able to answer the final question: long legs or short?</p><img src="https://counter.theconversation.com/content/62976/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anthony Blazevich does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The fastest male and female sprinters attain incredible top running speeds with peaks in excess of 44km per hour and 38km per hour, respectively, in the men’s and women’s 100m races.Anthony Blazevich, Professor of Biomechanics, Edith Cowan UniversityLicensed as Creative Commons – attribution, no derivatives.