Hip Abductors Strength and Endurance in Individuals with Recent and Long-Standing Patellofemoral Pain.

CONTEXT: Numerous studies report deficits in hip muscle performance in individuals with patellofemoral pain (PFP). However, the exact stage at which these deficits emerge and the impact of symptom duration remain unclear. OBJECTIVE: To compare hip abductor strength and endurance based on the presence or absence of PFP and its duration. DESIGN: Cross-sectional study. PATIENTS OR OTHER PARTICIPANTS: 68 with PFP and 29 pain-free controls. MAIN OUTCOME MEASURE(S): We evaluated isometric maximal strength, isometric endurance, and dynamic endurance of hip abductors. Comparisons were made between participants with PFP and pain-free controls and among different PFP duration subgroups (< 12 months, ≥ 12 months, ≤ 6 months, > 24 months) and pain-free controls. RESULTS: Hip abductor isometric strength (% body mass [BM]) was significantly lower in the PFP group (203.8 ± 46.8) and all PFP subgroups (< 12 months: 203.9 ± 57.0; > 12 months: 203.7 ± 42.2) (≤ 6 months: 205.1 ± 59.6; > 24 months: 207.7 ± 41.9), compared to pain-free controls (254.6 ± 60.3). However, no significant differences were found between PFP subgroups. There were also no significant differences in hip abductor isometric or dynamic endurance between PFP group and pain-free controls, or between PFP subgroups and pain free controls. CONCLUSIONS: Hip abductors strength deficits emerge early in the course of PFP. However, further studies are needed to understand the observed lack of difference in endurance.