Intra-rater test-retest reliability of hip abduction, internal and external rotation strength measurements in a healthy cohort using a handheld dynamometer and a portable stabilisation device: A pilot study

Abstract

Objective: To investigate the within-day and between-day test-retest reliability of hip abduction, internal rotation and external rotation strength measurements taken using a portable device externally stabilising a handheld dynamometer in healthy participants. Design: Observational study. Setting: Institute of Technology Carlow, Ireland - third level education institute. Participants: n = 18 (11 males and 7 females) healthy participants, who participate in a field sport for more than two hours per week, recruited via convenience sampling. Interventions: N/A Main Outcome Measures: Hip abduction, internal rotation and external rotation peak force during a maximal voluntary isometric contraction (N). The three best values recorded for each movement, for each day were used to analyse within-day and between-day test-retest reliability. Intra-class correlation coefficients, coefficients of variance, standard error of measurement and minimal detectable change statistics were also calculated. Results: External fixation of a handheld dynamometer produced excellent test-retest reliability for within-day (ICC’s > 0.934) and between-day (ICC’s > 0.802) contexts. Conclusions: Clinical measurements of hip strength can be performed reliably, efficiently and cost effectively using the methods described. Furthermore, the use of external fixation eliminates the influence of tester strength on the HHD measurements.