A group of Penn State researchers report that foot and ankle structure may make the difference between winning or losing as a sprinter.

The researchers took MRI images of the right foot and ankle of eight adult male sprinters and eight otherwise similar men who had never trained or competed as sprinters.

They found that the sprinters’ Achilles tendon lever arms were an average of 12% shorter, the combined length of the bones of their big toes was an average of 6.2% longer, and the length of the sprinters’ first metatarsal was 4.3% longer than those of the non-sprinters.

If you compare the ankle and foot to a lever it makes sense that a shorter handle (the Achilles tendon lever arm) moves a longer working end (forefoot) farther and faster.

A computer model showed that the combination allows the calf muscle to do more work during the acceleration phase of the race — the key to sprinting success.

While other physical factors such as muscle fiber type contribute to sprinting success, this information adds another piece to the puzzle. The researchers say this finding may also lead to a scan that could predict older adults’ risk of developing mobility problems (perhaps inspiring those at higher risk to maintain muscle strength) or even the development of a surgical option for helping people with severe mobility problems.