Shoulder Joint and Muscle Characteristics in the Recreational Weight Training Population

Signature Grand, Davie, Florida, USA

Objective. The purpose of this study was to investigate shoulder joint and muscle characteristics in the recreational weight-training (RWT) population to determine specific risk-related adaptations that may occur from participation. Background. Shoulder disorders attributed to weight-training are well documented in the literature; however, a paucity of evidence-based research exists to describe risk factors inherent to participation. Methods. Ninety male participants ages 19-47 (mean age 28.9), including 60 individuals who participated in upper extremity RWT and 30 controls with no record of RWT participation were recruited. Active range of motion (AROM), posterior shoulder tightness (PST), adjusted strength values and strength ratios were compared between the RWT participants and control group. Results. Significant mobility differences were present (p < .001) between the groups. RWT participants had decreased mobility when compared to the control group for all AROM measurements with the exception of external rotation which was greater. Strength ratios were significantly greater in the RWT group (p < .001) implying agonist/antagonist muscle imbalances. Conclusion. RWT participants are predisposed to strength and mobility imbalances as a result of training. The imbalances identified have been associated with shoulder disorders in the general and athletic population, thus may place RWT participants at risk for injury. Exercise selection that mitigates strength and mobility imbalances may serve to prevent injury in this population. Clinicians and strength and conditioning professionals should consider the biomechanical stresses and adaptations associated with RWT when prescribing upper extremity exercises.