Walking speed - rather than hip pain - influences hip moments in individuals with and without mild hip pain.

Individuals with hip pain are often reported to walk with reduced sagittal and frontal internal hip moments compared to pain-free controls. However, these outcomes are frequently observed at self-selected walking speeds, which may influence group differences due to the known effects of speed on joint moments. This study investigated whether peak sagittal and frontal hip moments differ between individuals with and without hip pain when walking at the same speed, and how hip moments change with increasing speeds. Participants with hip pain (n = 135) and pain-free controls (n = 57) walked on an instrumented treadmill at three speeds - prescribed (1.25 m/s), preferred, and fast (125 % preferred). Peak internal hip extension, flexion, abduction, and adduction moments were calculated and normalized to body mass. We used generalized linear models with a Generalized Estimating Equation correction to assess group, speed, and interaction effects. At the prescribed speed, we observed no group differences for any peak hip moment. At the preferred and fast speeds, hip moments increased with speed (p < 0.001 for all), but no group or group-by-speed interaction effects were observed. These findings suggest that within this active cohort, walking speed, rather than group (hip pain vs. pain-free), affected the peak hip moments during walking. Individuals with and without hip pain demonstrated similar hip moment magnitudes when walking at the same speed and responded similarly to increased speed. For clinicians and researchers, these results highlight the importance of considering walking speed as a key variable when assessing gait or conducting biomechanical comparisons across painful and pain-free populations.