Shoulder muscle recruitment patterns and related biomechanics during upper extremity sports.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing kinematic, kinetic, and electromyographic literature without systematic review methodology.
PubMed 19530752 · doi:10.2165/00007256-200939070-00004
What was done
The authors synthesized electromyographic (EMG), kinematic, and kinetic literature describing shoulder and scapular muscle recruitment across several upper-extremity sports: baseball pitching and hitting, American football passing, windmill softball pitching, volleyball serving and spiking, tennis serving and volleying, and the golf swing.
What was found
Distractive shoulder forces during overhead throwing reach 80% to 120% of body weight during arm cocking and deceleration. Peak rotator cuff activation ranges from 49% to 99% of maximum voluntary isometric contraction (MVIC) during cocking and 37% to 84% MVIC during deceleration in baseball pitching, versus 41% to 67% MVIC (cocking) and 86% to 95% MVIC (deceleration) in football passing. Peak rotator cuff activity reaches 75% to 93% MVIC in windmill softball pitching, 54% to 71% MVIC in volleyball serving/spiking, 40% to 113% MVIC in tennis serving/volleying, 28% to 39% MVIC in baseball hitting, and 28% to 68% MVIC in the golf swing. Baseball pitching elicits high peak scapular activity during cocking and deceleration: serratus anterior (69% to 106% MVIC), trapezius (51% to 78% MVIC), rhomboids (41% to 45% MVIC), and levator scapulae (33% to 72% MVIC). Peak serratus anterior activation reaches approximately 60% MVIC in softball pitching, 75% MVIC in tennis, 30% to 40% MVIC in baseball hitting, and 70% MVIC in golf.
Why it matters
The review maps muscle activation timings and magnitudes across sports, identifying the specific phases (such as cocking and deceleration) where rotator cuff and scapular stabilizers are under highest demand to inform training and rehabilitation.
Limits
The abstract reflects a narrative rather than systematic review design, with no study selection criteria, risk-of-bias assessment, or total participant count provided. Surface and fine-wire EMG values may be confounded across heterogeneous studies by differing normalization protocols, electrode placements, and athlete skill levels.