Comparison of Knee Muscle Balance at Different Knee Flexion Angles between Patients with Patellofemoral Pain Syndrome with Healthy Subjects



Patients with patellofemoral pain syndrome (PFPS) have been found to have a knee muscle imbalance that can be investigated by conventional concentric strength ratio of hamstrings to quadriceps (H:Q). The aim of this study was to compare, at different knee angles and the angle at peak torque, between healthy and PFPS subjects. Thirty-four subjects (23 males, 11 females) participated in this study. Participants were tested by the isokinetic concentric strength-open kinetic chain (OKC) procedure at 60 °/sec. The H:Q ratio was recorded and compared at knee flexion angles 15, 30, 45, 60 and 75 degrees and the angle at knee peak torque between healthy and PFPS subjects. The H:Q ratio in PFPS subjects was significantly greater than healthy subjects at knee flexion angles 15, 30, 45, 60 and 75 degrees. The measurement of H:Q ratio at specific knee angles may be a suitable clinical technique to represent the specific angle of knee muscle imbalance in PFPS patients that have been recommended to improve their quadricep muscle strength in counterbalance to the hamstring muscle.


Hamstrings to quadriceps ratio, patellofemoral pain syndrome, muscle balance, isokinetic

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