“..the back of the heel bone where the Achilles tendon attaches, was proportional to the runner's efficiency. The shorter this distance, the greater is the force applied to stretch the tendon - and the more energy is stored in it. This means that people with shorter distances are more efficient runners, using less energy to run for longer.
Raichlen then turned to Neanderthal skeletons, and found that our distant cousins' heel bones were consistently longer than ours. Neanderthals, he concludes, would have lost a race against Homo sapiens.”
Storing energy in my tendon, is a skill I use most every day as I sit on the couch and watch TV. I am purposely storing enough energy in my tendons to race to the kitchen, hunt down some sandwich meat, gather some chips, and get back to the TV before the commercials are over.