How human bodies are designed to make running tough on the legs
Researchers hope study findings will help in the design of better running shoes
The impact of running is almost entirely absorbed before vibrations reach the upper body, scientists have found.
Researchers believe runners compensate for the repetitive stress of their footfalls, which is known to cause muscular and skeletal injuries, by altering their stride so shock does not affect their torso.
Delphine Chadefaux, a post-doctoral researcher at Aix-Marseille University in France, wired up 10 recreational runners to find out how they adapted.
She found that while barefoot runners experienced four times as much shock energy in their feet, the bodies of both barefoot and shoe-wearing joggers had dispersed most of that vibration before it reached hip level.
According to Science Daily, she told an acoustic science conference in Boston: "Many of the studies involved in running or shoe development do not focus enough on shock propagation.
"We would eventually like to use the insights that we garner to advance the collective understanding of how to prevent running injuries and design better running shoes."
The study detected a "strategy set up by the neuro-musculoskeletal system to protect" the upper body.
It means, however, that the feet, shins and knees bear the brunt of the shock.
Over time this can lead to injuries like muscle fatigue, shin splints and "runner's knee".