Musculoskeletal screening to detect asymmetry in swimming

Abstract

Objectives: To investigate the influence of asymmetry of clinical strength musculoskeletal screening measures and 3D kinematic movements on bilateral hand-force performance measures in swimmers.

Design: Cross-sectional.

Setting: Institutional.

Participants: 32 national-ranked junior swimmers, 100 m freestyle time (mean (SD), 60.68 s (4.81)).

Main outcome measurements: Screened clinical strength, kinematic movements, and bilateral hand-force were measured. Asymmetry was defined as a percentage difference greater than 10 percent, either left (negative) or right (positive) for all variables.

Results: Asymmetry of the clinical strength measures was found in ∼85% of swimmers. Athletes with symmetry of all clinical strength measures displayed symmetrical bilateral hand force production. Approximately 50% of clinically asymmetrical swimmers were able to compensate, due to summated muscle symmetry and/or an altered kinematic movement pattern, and generate symmetrical hand force.

Conclusions: Symmetry of clinical strength was directly related to symmetrical force output. It is important to connect the clinical screening results to the sport-specific performance measures to ensure functional and valid screening is undertaken. Clinicians should aim for symmetry of strength in order to minimise the requirement for compensatory strategies.

Keywords: Asymmetry; Clinical strength; Screening; Swimming.