Weight-Bearing Versus Traditional Strength Assessments of the Hip Musculature

Context Traditional nonweight-bearing (NWB) hip-strength assessments may not directly translate to functional strength during weight-bearing (WB) activity. How NWB assessments of hip muscle strength compare with WB assessments in various positions is currently unknown. Objective To determine the magnitude of the differences and correlations between NWB hip strength and WB functional strength during the squatting and lunge (LNG) positions in female athletes. Design Crossover design. Setting Laboratory. Patients or Other Participants Female athletes (N = 51, age = 16.2 ± 3.5 years, height = 161.5 ± 8.3 cm, mass = 58.3 ± 11.6 kg). Intervention(s) Isometric resistance (N/kg) was determined for the dominant and nondominant limbs via WB assessments (squat-bilateral [legs tested simultaneously], squat-unilateral, and lunge positions) and NWB assessments (hip external rotation [HER], hip extension [HEXT], and hip abduction [HAB]). Main Outcome Measure(s) To compare differences between positions (P ≤ .05), we used effect sizes (d) and matched-pairs t tests, and we calculated Pearson r and R2 values. Results During the squat-bilateral on the dominant limb, females produced the most hip torque (6.13 ± 1.12 N/kg). The magnitudes of differences were very large compared with HER (3.96 ± 0.83, d = 2.2), HEXT (3.22 ± 0.69, d = 3.2), and HAB (3.80 ± 1.01, d = 2.2; all P values ≤ .01), and positions were moderately correlated (r = 0.347–0.419, R2 = 0.12–0.18). The lunge position produced the least amount of torque in the dominant limb (2.44 ± 0.48 N/kg) compared with HER (d = −2.3), HEXT (d = −1.3), and HAB (d = −1.7; all P values ≤ .001), and correlations were small to moderate (r = 0.236–0.310, R2 = 0.06–0.10). Conclusions Strength in WB positions was different than strength evaluated using traditional NWB assessments in female athletes. Weight-bearing tests may provide clinicians with additional information regarding strength and function.