A Comparison of Traditional Versus Weight-Bearing Hip Strength Assessment.

Abstract

A Comparison of Weight-Bearing and Traditional Hip Strength Assessments Urbi, AK, Freemyer, BG, Stickley, CD; Department of Kinesiology and Rehabilitation Science, University of Hawai’i, Mānoa, Honolulu, HI Context: Hip strength assessment in a weight-bearing (WB) position has been advocated to be an alternative and more meaningful method of muscles testing compared to traditional non-weight-bearing (NWB) assessments. Though shown to be reliable, no other studies have examined the differences between WB and NWB strength. Objective: To determine the hip strength differences between WB assessments and NWB assessments in healthy female athletes. Design: Prospective experimental study. Setting: University Laboratory. Patients: Female athletes (N=51, 16.2 ± 3.5 years, ranged 12-25 years old, 161.5 ± 8.32 cm, 58.3 ± 11.6 kg) that participated in soccer, basketball, and volleyball, were recruited from local universities and high schools. Interventions: Hip strength was quantified by a single examiner (AU) using two MicroFET2 handheld dynamometers (HHDs) to determine force (N). The WB assessments was conducted to test the hip abductor and external rotator strength in a standing double-leg squat and lunge position. Two HHDs was simultaneously utilized only in the squat bilaterally (SQ-B) and one HHD was used in the squat unilaterally (SQU) and lunge (LNG) assessments. The NWB assessments was conducted to individually test hip abduction (HAB), extension (HEXT), and external rotation (HER) strength. A break test was performed with the valgus force applied proximal to the knee for all strength assessments besides the HEXT assessment. The peak strength of three trials was normalized to body mass (N/kg). Main Outcome Measures: Data met t-test assumptions. Each WB assessment (SQB, SQ-U, LNG) were separately compared to each NWB assessment (HAB, HEXT, HAB) in order to evaluate the differences in a matched pairs t-test (t) with effect size (d) to determine the difference magnitude. A Pearson’s Product-Moment Correlation Coefficients (r) was calculated to determine the correlation between the WB and NWB assessments. Results: Significant differences was observed between the WB and NWB assessments, except for the right leg SQ-U and HER (t=1.83, p=0.07, d=0.24). Conversely, participants were significantly weaker in the LNG versus NWB assessments. Significant correlations between WB and NWB assessments ranged from low to moderate (r=0.28 to 0.58) when examining the right and left leg. Conclusions: The results of our study demonstrate that there is a difference between the WB and NWB hip strength assessments. The low to moderate correlations demonstrates different hip muscle patterns. We recommend the SQ-B assessment to evaluate the hip abductor and external rotator in WB position. This information is important to consider as it demonstrates that the gluteus maximus provides dynamic stability in the WB assessment and provide unique information from an injury prevention and treatment perspective. Word Count: 412