Shoulder joint and muscle characteristics among healthy female recreational weight training participants.

Shoulder disorders attributed to weight training are well documented in the literature, with prevalence rates exceeding that of the general population. Although researchers have identified both intrinsic and extrinsic risk factors among men who participate in weight training, a paucity of evidence-based research exists to describe risk factors inherent to participation among women. The purpose of this study was to investigate shoulder joint and muscle characteristics among healthy female recreational weight training (RWT) participants to determine specific risk-related adaptations that may occur from training. Eighty-eight women aged 18-55 (mean 26.8), including 57 who participated in upper extremity RWT and 31 controls with no record of RWT participation were recruited. Active range of motion (AROM), posterior shoulder tightness (PST), glenohumeral (GH) joint laxity, body weight-adjusted strength and strength ratios of force couples were compared between the RWT and control groups. Statistical analysis identified significant differences (p ≤ 0.004) between groups when analyzing shoulder internal rotation AROM, PST, and joint laxity. The RWT participants had decreased internal rotation AROM, greater PST, and anterior GH joint hyperlaxity when compared to the control group. No differences in strength ratios between groups were identified (p ≥ 0.109) implying the absence of weight training-induced muscle imbalances. The findings of this investigation suggest that female RWT participants are predisposed to mobility imbalances as a result of training. The imbalances identified in this investigation have been associated with shoulder disorders in both the general and athletic population thus may place weight training participants at risk for injury. Clinicians and strength and conditioning professionals should consider the biomechanical stresses and adaptations associated with RWT when prescribing exercises. Exercise prescription that mitigates mobility imbalances may serve to prevent injury in this population.