He has recently apologised for the timing of the comments. In my humble observation, it is only double-leg amputees who can “benefit” from lengthening their blades as a single-leg amputee can only have a blade that is the same length as their remaining leg. As these “blades” have developed one would guess there is some advantage over previous prosthetics.
The blades can vary in length, stiffness, angle, rebound etc.. It must be a nightmare for the IPC as they seek to ensure that you gain no advantage from the technology and to ensure there is no “unrealistic enhancement of stride length”.
The prosthetics are to “ensure both legs are of equal length but not for any other purpose, and they must not otherwise provide assistance to the athlete”.