Article

Objectives: To evaluate the reliability (intertrial, interevaluator) and the concurrent validity of strength measurements obtained with a chair-fixed dynamometer and to recommend a clinical protocol that minimizes standard error of measurement (SEM). Design: Within-session repeated measures of maximal static strength of knee flexors and extensors at 30 degrees and 60 degrees of flexion on the chair-fixed and Cybex dynamometers. Setting: Ambulatory physiotherapy department of a rehabilitation hospital. Participants: Convenience sample of 50 subjects with total hip (n=25) or knee (n=25) arthroplasty. Interventions: Not applicable. Main Outcome Measures: Reliability was quantified by indices of dependability and corresponding SEMs estimated with the generalizability theory, whereas coefficients of correlation were used to assess the validity. Results: Indices of dependability confirmed excellent intertrial (0.98-1.00) and a very good interevaluator (.92-99) reliability for the strength measures obtained for different movements and positions. An average of 3 trials minimized the magnitude of the SEMs (> 2Nm for all measurements). When comparing the strength values obtained with the Cybex dynamometer to those measured with the chair-fixed dynamometer, strongest relations were attained when the tested knee was positioned at 60 degrees compared with 30 degrees for subjects with a total knee (.78-92 vs.87-93) or hip (33-85 vs.86-91) arthroplasty. Conclusions: A clinical protocol averaging 3 trials with the knee positioned at 60 degrees after a familiarization period. Both for knee flexors and extensors, performed by a trained therapist is recommended to minimize measurement errors on strength values measured with the chair-fixed dynamometer.

Langue : ANGLAIS