Sex differences in regional pectoralis major activation

Limited research has investigated sex differences in muscle activation, especially in the upper extremity. This study used high-density electromyography to investigate sex differences in activation of the clavicular (PecC) and sternocostal (PecS) regions of the pectoralis major in three different arm positions during two exertions. Differences existed within all positions comparing sex and region. Further, females generally activated the PecC over PecS during both exertion levels in internal rotation. This has implications for clinical procedures involving the pectoralis major in both males and females.