The reliability of strength tests performed in elevated shoulder positions using a hand-held dynamometer
Context: The reliable measurement of shoulder strength is important when assessing the athlete involved in overhead activities. Swimmers' shoulders are subject to repetitive humeral elevation and consequently have a high risk of developing movement control issues and pain. Shoulder strength tests performed in positions of elevation assist with the detection of strength deficits that may impact on injury and performance. The reliability of isometric strength tests performed in positions of humeral elevation without manual stabilisation, which is a typical clinical scenario, has not been established.
Objective: To establish the relative and absolute intra-rater reliability of shoulder strength tests functional to swimming in three body positions commonly used in the clinical setting.
Design: Repeated measures, reliability study.
Setting: Research laboratory.
Subjects: Fifteen university students and staff (mean ± SD age 24 ± 8.2 y) volunteered for the study.
Intervention: Isometric shoulder strength tests were performed in positions of humeral elevation (flexion and extension in 140° abduction in the scapular plane; internal and external rotation in 90° abduction) on subjects without shoulder pain in supine, prone and sitting. Subjects were tested by one examiner with a hand-held dynamometer and retested after 48 hours.
Main Outcome Measures: Relative reliability (ICC3,1) values with 95% CI. Absolute reliability was reported by minimal detectable change (MDC).
Results: Good to excellent intra-rater reliability was found for all shoulder strength tests (ICC 0.87-0.99). Intra-rater reliability was not affected by body position. MDC% was less than 16% for every test and less than or equal to 11% for tests performed in supine.
Conclusions: Shoulder flexion, extension, internal and external rotation strength tests performed in humeral elevation demonstrated excellent to good intra-rater reliability regardless of body position. A strength change of more than 15% in any position can be considered meaningful.
Publication titleJournal of Sport Rehabilitation
IssueTechnical Report 20
Department/SchoolSchool of Health Sciences
PublisherHuman Kinetics Publ Inc
Place of publicationUnited States
Rights statementAccepted author manuscript version reprinted, by permission, from Journal of Sport Rehabilitation, 2016 (in press). Copyright Human Kinetics, Inc.