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From The Field - September 2010

Posted: September 3, 2010

Most ACL injuries are due to rotational torque in the joint. Injury risk is often evaluated by measuring the amount of resistance to shoe rotation.

Most ACL injuries are due to rotational torque in the joint. Injury risk is often evaluated by measuring the amount of resistance to shoe rotation. Researchers have postulated that as resistance to rotation increases, the potential for lower extremity injuries increases because a player’s cleats will not “release” from the surface. Certainly a shoe — surface — player weight combination that produces high rotational resistance is not preferred, but researchers are reporting that non-contact ACL injuries are the result of a complex set of variables including speed to peak rotational resistance, surface hardness, and knee flexion at the time of quad muscle firing to name a few.

As you can imagine, measuring traction is not a simple task. At Penn State’s Center for Sports Surface Research, we have developed a traction testing device named ‘PennFoot’. Pennfoot’s artificial leg and foot assembly allows us to measure both linear and rotational traction with any shoe on any surface. Additionally, we can simulate various player weights, giving us the opportunity to compare traction measurements for athletes from the Pop Warner league to the NFL. Beginning in 2001, we have been measuring traction on multiple synthetic turf products and publishing the results on our Web site: ssrc.psu.edu. Here you will find traction information from research plots that have been exposed to simulated heavy use for the past nine years.

Andrew S. McNitt is Associate Professor of Soil Science — Turfgrass and Director of Penn State’s Sports Surface Research Center, The Pennsylvania State University