Effects of Hip Range of Motion and Strength on Compensatory Lumbar Movement: A Path Analysis

Objective: To examine the effects of hip joint range of motion (ROM) and strength on compensatory lumbar movement (CLM) in healthy adults using path analysis. Design: Cross-sectional observational study with structural equation modeling. Methods: Forty healthy university students in their twenties participated. Hip ROM was measured in flexion, extension, internal, and external rotation using a digital goniometer. Hip strength was assessed through maximal isometric contractions using a handheld dynamometer. CLM was evaluated as pelvic tilt angle during side-lying hip external rotation using an inclinometer. Standardized variables were analysed with path analysis to estimate direct, indirect, and total effects. Results: Hip ROM and strength were not significant predictors of each other (β＝ －0.090; β＝ －0.034). Direct effects on CLM were moderate for ROM (β＝ 0.497) and weak for strength (β＝ 0.233), though neither reached significance. No indirect effects were observed. Total effects indicated that ROM (β＝ 0.476) had a relatively stronger influence on CLM compared with strength (β＝ 0.232). Conclusions: Hip ROM showed a stronger relationship with compensatory lumbar movement than hip strength, despite a lack of statistical significance. These findings highlight the clinical importance of hip mobility assessment and management to reduce compensatory lumbar strategies and promote efficient trunk stability.