EFFECTS OF GENDER AND HAND DOMINANCE ON SIZE OF THE LOWER TRAPEZIUS MUSCLE

Introduction: The influence of gender and hand dominance on the size of the lower trapezius muscle has not been studied. We aimed to identify the effects of gender and hand dominance on thickness of this muscle. Methods: Thirty healthy subjects (15 men and 15 women) were recruited for the study. The thickness of the lower trapezius muscles was measured bilaterally at the level of T8 at rest and with contraction at 130 degrees of shoulder abduction using ultrasound imaging. Results: Men had significantly greater thickness of the lower trapezius muscle than women, both at rest and with contraction (P < 0.01). Greater lower trapezius muscle thickness was found on the dominant side compared with the non-dominant side (P < 0.05). Conclusion: Gender and side dominance differences should be controlled for when investigating lower trapezius muscle thickness.