Thigh muscles imbalance leads to the increase of lower extremity injury in long-distance running. This study aimed to compare isokinetic parameter of bilateral strength imbalance in long distance runners with and without history of anterior knee pain. Forty-eight long distance runners; 26 males and 22 females were divided into two groups 1) with history of anterior knee pain and 2) no history of anterior knee pain. Knee flexors and extensors were assessed by Biodex isokinetic dynamometer at 3 angular velocities. The results showed that the quadriceps peak torque had significant differences at 60 o.s-1 and 120 o .s-1 between groups, p=0.007 and 0.038 respectively. The quadriceps total work at the speed of 120 o.s-1 and 180 o.s-1 demonstrated significant difference between two groups, p<0.001 and 0.044 respectively. This finding found the difference between the long-distance runners with and without the history of anterior knee pain, by which an appropriate intervention program to promote longdistance runners’ performance should be emphasized in further studies.
