In order to prevent sports injuries, physiological assessments and exercises before the competitions are necessary. The physiological indicators which allow us to predict the increased risk for the sports injuries can help us plan more effective sports and rehabilitation programs.

Nineteen basketball players were evaluated for the isokinetic strength and balance of the knees in order to determine their relationship to sports injuries. The subjects were divided into the knee injured group and the control group. The results were as follows:

1) No significant difference was found between the injured group and the control group in the isokinetic peak torques of the hamstrings and the quadriceps; and while the angular velocity increased, the peak torques of the hamstrings and the quadriceps decreased(p<0.01).

2) The average hamstrings/quadriceps ratios between the two groups were not significantly different, but the ratio increased as the angular velocity increased (p<0.05).

3) The muscle imbalance of more than 15% was found more frequently in the injured group between the injured leg and the uninjured leg(between the right and the left leg for the uninjured group) at the angular velocity of 300°/sec(p<0.05). However, when the hamstings/quadriceps ratio was less than 50% or more than 80%, there was no significant difference between the two groups.

These results demonstrate that the muscle imbalance of two knees at high velocity may be one of the risk factors of the knee injuries in basketball players. Further prospective study of the players with the predetermined muscle imbalance is needed to determine its role as the physiological prognostic indicator for the sports injury.