STATE COLLEGE, Pa., Nov. 3 (UPI) -- U.S. scientists say they've determined sprinters have longer toes and a shorter distance from the ankle to the back of the heel, compared with non-sprinters.
Pennsylvania State University Associate Professor Stephen Piazza and Sabrina Lee, his former graduate student, studied 12 sprinters and long jumpers from Lock Haven University, and 12 non-sprinters of the same height.
In addition to taking measurements of the athletes' feet and ankles, the researchers said they computed the leverage force of the Achilles tendon from measures of the motion of the ankle and tendon derived from ultrasound images.
They discovered the toes of sprinters were more than one-third of an inch longer than the toes of non-sprinters. The researchers said the longer toes gave sprinters a longer time to push against the ground, helping them outperform non-sprinters.
"The lever arms (the distance between the tendon and center of rotation of the ankle) were significantly shorter -- about 25 percent shorter -- in sprinters," said Piazza. He said that occurs because the lever arms are shorter and the muscles of sprinters contract less and more slowly than non-sprinters, helping the sprinters exert greater force.
The Penn State researcher cautions that while the study could be a piece of the puzzle in determining who might be a good sprinter, other physiological components such as body type, cardiovascular physiology and muscle fiber types should also be taken into account.
The research appears in the Journal of Experimental Biology.
