The Influence of hamstring extensibility on spinal and pelvic postures in highly trained paddlers

Objectives. To determine whether the degree of hamstring muscle extensibility influences the sagittal spinal curvatures in standing and maximal trunk flexion on young athletes. Methods. Forty-two young elite kayakers (mean age: 15.09 ± 0.63 years) were recruited. Thoracic and lumbar curvatures and pelvic position were evaluated with a Spinal Mouse system in standing position and maximal trunk flexion with knees extended (toe-touch test) and flexed. Hamstring muscle extensibility was determined by passive straight leg raise test (PSLR). The sample was divided into two groups with regard to straight leg raise angle (PSLR < 80º, n=20, and PSLR ≥ 80º, n=20). Results. Subjects with lower extensibility presented higher thoracic angle and a more posterior pelvic tilt in maximal trunk flexion. However, no significant differences were found between both groups when standing. The lumbar curve was not affected by hamstring extensibility. Conclusions. Lower hamstring extensibility is related to increased thoracic curve and more posterior pelvic tilt when maximal trunk flexion is performed, which can overload the spine. A systematic stretching programme to improve hamstring extensibility should be incorporated into training activities.