New study: Pattern of force on the ground is due to the motion of two parts of the body

Reporter Stacy Liberatore with London’s Daily Mail newspaper covered the research of Peter Weyand and the SMU Locomotor Laboratory. Weyand, who is Glenn Simmons Professor of Applied Physiology and professor of biomechanics in the Department of Applied Physiology and Wellness in SMU’s Annette Caldwell Simmons School of Education and Human Development, is the director of the Locomotor Lab.

Other authors on the study were Laurence Ryan, a physicist and research engineer in the lab, and
Kenneth Clark , previously with the lab and now an assistant professor in the Department of Kinesiology at West Chester University in West Chester, Penn.

The three have developed a concise approach to understanding the mechanics of human running. The research has immediate application for running performance, injury prevention, rehab and the individualized design of running shoes, orthotics and prostheses. The work integrates classic physics and human anatomy to link the motion of individual runners to their patterns of force application on the ground — during jogging, sprinting and at all speeds in between.

The Daily Mail article, “Researchers reveal the mechanics of running is simpler than thought – and it could revolutionise shoe design,” published Jan. 31, 2017.

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By Stacy Liberatore
Daily Mail

A study has found a new explanation for the basic mechanics of human running.

While observing Olympic-caliber sprinters, researchers discovered that a runner’s pattern of force application on the ground is due to the motion of just two parts of the body: the contacting leg and the rest of the body.

The new approach could help create new patterns to optimize the design of running shoes, orthoses and prosthetics, as experts are able to see exactly how a person runs.

The Southern Methodist University (SMU) researchers explained that the basic concept of their ‘two-mass model’ is relatively simple — a runner’s pattern of force application on the ground is due to the motion of two parts of the body: the lower portion of the leg that is contacting the ground, and the sum total of the rest of the body.

The force contributions of the two body parts are each predicted from their largely independent motions when they have foot-ground contact.

And then combined to predict the overall pattern.

The final prediction relies only upon classical physics and a characteristic link between the force and motion for the two body parts.

‘Our model inputs are limited to contact time on the ground, time in the air, and the motion of the ankle or lower limb.

‘From three basic stride variables we are able to predict the full pattern of ground-force application,’ said Laurence Ryan, who is a physicist and research engineer at SMU’s Locomotor Performance Laboratory.

‘The approach opens up inexpensive ways to predict the ground reaction forces and tissue loading rates.’

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