Three dimensional kinematics of visually classified lower extremity movement patterns during a single leg squat among people with chronic hip joint pain

Describe the proportional occurrence of visually determined, lower extremity movement patterns (dynamic knee valgus [DKVal], neutral [NEU], dynamic knee varus [DKVar]) during a single leg squat (SLSquat) among patients with chronic hip joint pain (CHJP). Compare 3D hip and pelvic kinematics among the categories and determine whether within-session movement pattern changes are possible among those who demonstrate DKVal or DKVar. Design: Cross-sectional. Setting: Movement science laboratory. Participants: 36 patients with CHJP (18 to 40 years). Main Outcome Measures: Visually based classification of lower extremity movement and 3D kinematic angles of hip and pelvis during SLSquat, performed under usual (self-selected) and modified (therapist instruction) conditions. Results: Based on visual appraisal, 14 patients demonstrated DKVal, 22 demonstrated NEU and none demonstrated DKVar. Those with DKVal demonstrated greater hip adduction (23.5 + 5.7º vs. 16.0 + 5.7º, p < 0.001) and internal rotation (7.4 + 7.1º vs. 1.6 + 7.0º, p = 0.023) than those with NEU. Compared to the usual condition, the DKVal group demonstrated significant decrease in hip adduction (23.5 + 5.7° vs. 20.9 + 5.8°, p = 0.001) and internal rotation (7.4 + 7.1° vs. 5.3 + 7.8°, p = .050) in the modified condition. Conclusions: Patients with CHJP demonstrated 2 movement patterns, DKVal and NEU. Compared to NEU, those with DKVal demonstrated greater hip adduction and internal rotation motion and were able to make small modifications to their movement pattern with therapist instruction.