Fatigue May Increase Risk of Knee Injuries

Have you ever witnessed someone tear an anterior cruciate ligament (ACL)? Even if you have, it is likely when you hear of that happening to someone that you envision it happening after a powerful collision. However, 70 percent of ACL injuries result from scenarios that did not involve contact.

This does not just happen to “Average Joes” and “Weekend Warriors” but to collegiate athletes, too. Many college football fans remember when Todd Gurley tore his ACL after what looked like a routine run this past season.

Many have speculated why that is the case and a new study may yield some answers.

The Journal of Athletic Training published a study finding that knee joint biomechanics may be altered in a fatigued state. This means that the later in the game it is, the higher the risk of an athlete attaining a noncontact injury, such as an ACL tear in the knee. That was certainly the case for Gurley.

How did they arrive at this conclusion? Researchers recruited ten athletes (five male, five female, all age 25) with no history of knee injuries to their dominant leg to participate in the study.

Each participant wore motion analysis sensors to measure anterior tibial translation – or what happened when various amounts of force were applied to the bottom of their foot, which simulated a landing from a jump.

The authors found a 6% increase in compressive force, a 28% increase in knee flexion range of motion and a 22% increase in anterior tibial translation after the fatiguing exercise compared with before.

While more research needs to be conducted before this becomes conclusive, Sports Medicine Research analyzed the study and suggests that injury prevention, strength and conditioning, and rehabilitation programs could help train movement strategies but that we cannot ignore the importance of endurance in delaying maximum fatigue.