Very intersting .

Just wondering peoples thoughts on this... Does this also give much more significance to Swing phase leg providing power in forward movement. The shorter the lever arm of the Achilles tendons the easier for the swing phase leg to bring the body forward ?

 

I agree a very interesting article. The swing phase leg only adds energy to the whole body when there is ankle push off. Ankle push off equal ankle joint power = joint moment x joint angular velocity. If there is no ankle plantar flexion then there is no power contribution from the ankle muscles. Without ankle power the swing leg pulls the body backward during the first half of swing and then pulls the body foward during the second half of swing. So, we can debate the semantics about the swing leg "powering gait", but unless there is ankle push off giving the swing leg additional energy then I feel it is not entirely accuarte to say that the swing leg powers gait.

One thing the article did not discuss, but made some assumptions about was where the center of pressure under the foot was. It was making the assumption that after heel off the center of pressure was at the tip of the toes. Someone should check and see if this assumption is accurate. Also if sprinters have longer toes, but the same length of foot, the metatarsal heads will be closer to the ankle axis and provide a smaller lever arm for ground reaction force to oppose ankle plantar flexion. There could be an interesting change in ground reaction force leverage as the force shifts from the metatarsal heads to the toes.

Interesting stuff to think about.

Regards,

Eric