Associations between changes in leg extensor muscle power and physical function after supervised exercise in patients with hip osteoarthritis. Secondary analysis from the hip booster trial.

Objective: To investigate associations between changes in leg extensor muscle power of the affected limb (ΔLEP) and changes in physical function after 12 weeks of progressive resistance training (PRT) or neuromuscular exercise (NEMEX) in patients with hip osteoarthritis. Design: Secondary analyses of a randomized controlled trial. From 160 participants enrolled in the clinical trial and cluster randomized to PRT (n â€‹= â€‹82) or NEMEX (n â€‹= â€‹78), a total of 147 (92%) had complete follow-up data and were included in the analyses. Simple linear and multivariate linear regression models estimated the crude and adjusted associations between ΔLEP normalized to body weight (watt/kg) and changes in performance-based and patient-reported measures of physical function. Results: Adjusted estimates [95% confidence intervals] showed associations between ΔLEP (watt/kg) and changes in 30-s chair stand test (ß: 2.34 [1.33; 3.35], R2: 0.13), 9-step timed stair climb test (ß: -1.47 [-2.09; -0.85], R2: 0.38), 40-m fast paced walking test (ß: -2.20 [-3.30; -1.11], R2: 0.09), Activities of Daily Life function (ß: 8.63 [3.16; 14.10], R2: 0.23) and Sport and Recreation function (ß: 10.57 [2.32; 18.82], R2: 0.21) subscales from the Hip disability and Osteoarthritis Outcomes Score. Group allocation to PRT did not lead to greater regression coefficients than in NEMEX. Conclusions: Changes in leg extensor muscle power after supervised exercise are consistently associated with changes in physical function across performance-based and patient-reported measures in patients with hip osteoarthritis. These associations seem to be independent of allocation to PRT or NEMEX.

Interrater, Test-retest Reliability of the Y Balance Test: A Reliability Study Including 51 Healthy Participants.

The aim was to determine the relative and absolute interrater, test-retest reliability of the Y-Balance Test (YBT) in a sample of healthy and active adults aged 18 to 50 years. The sample consisted of 51 healthy and active participants, 30 men and 21 women with a mean age of 28 ± 7 years. The YBT was performed on the right leg in the three test directions. Test and retest of the YBT were performed with a median interval of 15 days. The method for data collection was in line with the Y Balance Test Lower Quarter Protocol (YBT-LQ). The test was conducted by raters previously inexperienced in the use of the YBT. The relative reliability was reported as Intraclass Correlation Coefficient (ICC(2,1)). The absolute reliability was reported as Standard Error of Measurement (SEM) and Minimal Detectable Change (MDC). The ICC ranged from 0.79-0.86. SEM ranged from 2%-4%, indicating the measurement error at group level and MDC ranged from 5%-11%, indicating the measurement error at individual level. The YBT showed good relative and absolute reliability. The YBT is therefore considered suitable at both group and individual level in physically active populations.