Sex-based comparison of trunk flexors and extensors functional and contractile characteristics in young gymnasts

Purpose. Gymnastics is a sport characterized by acrobatic and postural strength exercises that require great trunk muscles activation and control. Males and females can be characterized by different morphological and neuromuscular characteristics of such muscles, and this might be of importance for training and injury prevention. The aim of this study was to measure different aspects of trunk flexors and extensors characteristics in a sample of young female and male gymnasts. Methods. Twenty-eight sub-elite adolescent female (n = 14, 16 y, 14-17) and male (n = 14, 17 y, 14-18) gymnasts participated in this cross-sectional study. Tensiomyography was used to assess muscle contractile properties of the rectus abdominis (m.RA) and erector spinae (m.ES), while muscle thickness was assessed for abdominal muscles and lumbar multifidus (m.LM) with ultrasound. Flexors, extensors, and lateral endurance tests were performed. Results. Females presented smaller m.ES radial displacement (p < 0.001, p & eta;(2) = 0.535), smaller internal oblique thickness (p < 0.001, p & eta;(2) = 0.543), and shorter lateral endurance (p = 0.002, p & eta;(2) = 0.302). A significant side x sex interaction was found for the external oblique thickness (p = 0.004, p & eta;(2) = 0.276). Conclusion. Present findings report sex-based differences in abdominal and lumbar muscles characteristics and support the development of different sex-based training and rehabilitation protocols in adolescent gymnasts.