Electromyographic analysis and phase definition of the overhead football throw

Background: The phases of the football throw need definition so that muscle activation patterns during the overhead football throw can be fully described. Hypothesis: Electromyographic analysis of shoulder musculature can better define muscle activation patterns during the football throw. Study Design: Descriptive anatomic study. Methods: Videos of 20 elite-level quarterbacks were reviewed to define phases of the overhead football throw; 14 recreational male athletes underwent electromyography and motion analysis testing. Results: Four sequential phases of the football throw were consistently observed. Early cocking (49% +/- 11% of throw) was initiated at rear foot plant and continued to maximal shoulder abduction and internal rotation. Late cocking (20% +/- 6%) started at maximal shoulder abduction and internal rotation and ended with maximal shoulder external rotation. The acceleration phase (15% +/- 4%) began with maximal shoulder external rotation and ended with ball release. Follow-through (16% +/- 5%) was defined as the phase from ball release to maximal horizontal adduction (across the body). Conclusion: The four phases demonstrated little variation in motion analysis and electromyographic activation between subjects and were associated with muscle activation patterns consistent with upper extremity movements. Clinical Relevance: A clearer understanding of muscle activation patterns may help to explain patterns of muscle injury and improve rehabilitation protocols in football-throwing athletes. (C) 2002 American Orthopaedic Society for Sports Medicine.