Question: what is the difference in maximum stored energy between the sprinters and the nonathletes?
Answer: The elastic energy stored in your tendons can contribute up to 35% of your energy needs when running. ... They find (on average) that the sprinters' tendons stretch 41 mm, while nonathletes' stretch only 33 mm. The spring constant for the tendon is the same for both groups, 33 N/mm.