Isokinetic muscle imbalance and knee-joint injuries. A prospective blind study.

One hundred and seventy-two randomly selected high-school football players underwent pre-season isokinetic muscle-testing to determine if there was any relationship between an imbalance in thigh-muscle function and the occurrence of knee injuries. Strength, power, power-endurance, and time to maximum tension were measured for the quadriceps and hamstring muscle groups for both lower extremities of each athlete. The resulting values were utilized to see if a difference of 10 per cent or more between the right and left extremities or between the mean and actual hamstring-to-quadriceps ratio of the individual extremity would result in more knee injuries. No such relationship was found.