Stephanie Lachapelle for Body1
Researchers at the Hospital for Special Surgery (HSS) have determined that athletes wearing cleats experience the least strain on their anterior cruciate ligament (ACL) on a natural grass surface, as compared to three other shoe-surface interactions.
Researchers tested the strain placed on the ACL by interactions involving Astroturf/turf shoe, modern playing turf/turf shoe, modern turf/cleat, and natural grass/cleat. The team used the knee, foot and ankle from eight cadavers to create a model to test the strain on the ACL. Each lower extremity was placed in a standing position with the knee at a 30 degree angle, the angle at which the ACL is most sensitive to stress. Weight was placed on the extremity to simulate the weight of an athlete’s body, and a plate under the contraption measured the load on the shoe-surface interface. This model simulates the way the shoe interacts with the ground surface during an actual athletic cut. "Our model looks at how forces travel up the kinetic chain, and that is something that should be looked at more closely, meaning you can't just look at the knee injuries by looking at the knee in isolation," said Mark Drakos, M.D., formerly an orthopedic fellow in the Sports Medicine and Shoulder Service at HSS.
The team found that the interaction between a cleat and natural grass placed a statistically lower strain on the ACL than the other tested interactions.
This study holds promise for the optimization of athletic fields. Dr. Drakos explains, "There are basically 200,000 ACL injuries every year in the United States alone…the reason that I think this is so interesting is because there are still environmental factors, which have yet to be optimized. We don't know all the science behind why ACL injuries may be more common on turf than on grass. This study starts developing some of the science behind that, so that it can be looked at more closely because, at the end of the day, I think we need to optimize some of those environmental factors."
The study appears in the January 2010 issue of the Journal of Biomechanical Engineering.
Read more about ACL Injuries in the Conditions Section of the Knee1 Education Center