Abstract:
Background: The weakness of hip abductor and external rotator muscles may result in altered hip and knee kinematics. Excessive hip adduction, hip internal rotation and knee valgus affect to increased patellofemoral joint stress and also contribute to patellofemoral pain syndrome. However, no study has investigated the effect of hip muscle strengthening program on hip and knee kinematics during step down in patellofemoral pain (PFP) persons.
Objectives: To investigate the effect of hip muscle strengthening program on hip adduction and knee valgus angles, and pain in females with and without PFP.
Methods: Fifteen females with PFP and fifteen females without PFP received hip strengthening program for 4 weeks. Hip muscle strength was measured by using hand-held dynamometer (HHD). Hip adduction and knee valgus angles during standing and step down were measured by using a video camera and Kinovea program version 0.8.15. Independent t-test was used to compare the hip and knee angles between PFP and control group.
Results: Both groups showed the significant increases in hip abductor and hip external rotator strength after performing hip strengthening program. PFP group exhibited significantly decreased knee valgus during step down task more than the control group (6.58, 0.47 degrees, p =.001). However, there was no significant differences in hip adduction during step down between PFP and control group (p=.138). Moreover, PFP group revealed significant improvement in the Kujala anterior knee pain scale (before 86.2, after 95.2, p < 0.001).
Conclusion: Hip strengthening program can increase hip muscle strength, decrease knee valgus and improve pain and function