The relationship between hip joint morphology and hip range of motion in circus performers with hip-related pain – A Cross-sectional Study

OBJECTIVE: To assess the relationship between hip joint morphology and hip range of motion (ROM) in circus performers with hip-related pain. STUDY DESIGN: Cross-sectional study. SETTING: Circus arts training facility. PARTICIPANTS: Adult student circus artists with hip-related pain (19 females, 11 males, age: 22 ± 3.4). MAIN OUTCOME MEASURES: The association between radiographic measures and ROM assessment was investigated using linear regression models controlling for age and sex. RESULTS: Thirty circus performers were included. A higher neck-shaft angle was associated with more external rotation ROM in prone (β0.69, 95%CI 0.13, 1.26), and more external rotation ROM in sitting (β0.68, 95%CI 0.10, 1.26). A higher alpha angle was associated with more hip flexion ROM (β0.35, 95%CI 0.03, 0.67) with a main effect of sex (F = -12.25, p = 0.032). CONCLUSION: The association between hip morphology and ROM may be unique in circus artists with hip-related pain, with neck-shaft angle and alpha angle showing an association with hip external rotation ROM and hip flexion ROM, respectively.