Trunk muscles’ characteristics in adolescent gymnasts with low back pain: a pilot study on the effects of a physiotherapy intervention including a postural reeducation program

Background: Trunk muscles’ function and characteristics are of great importance for both static and dynamic tasks in different sports, and abnormalities of trunk flexors and extensors might be associated with low back pain (LBP). The aim of this study was to provide a comprehensive evaluation of the functional, morphological and contractile properties in trunk flexors and extensors of young gymnasts with and without LBP. Methods: Young gymnasts (14/25 females, 14–18 y) were screened for the presence of chronic LBP. Abdominal and lumbar muscles were tested for function (McGill’s endurance tests), thickness (ultrasound), and contractile responses (tensiomyography). An 8-sessions physiotherapy intervention including postural reeducation was performed by a subsample of 10 subjects with LBP. Results: LBP was found to be associated to higher flexors-to-extensors endurance ratio (OR 11.250, 95% CI: 1.647–76.849, p = 0.014), reduced mean lumbar multifidus thickness (OR 16.500, 95% CI: 2.246–121.228, p = 0.006), and reduced mean erector spinae radial displacement (OR 16.500, 95% CI: 2.246–121.228, p = 0.006). The physiotherapy intervention was found to reduce LBP symptoms and it was associated with a significant improvement in the flexors-to-extensors ratio (p < 0.001). Conclusions: This study provides preliminary evidence of functional, morphological, and contractile trunk muscles’ alterations associated with chronic LBP in young gymnasts, and presents the effects of a postural reeducation program on symptoms and muscles’ functional properties.