Influence of hamstring extensibility on sagittal spinal curvatures and pelvic tilt in highly trained young kayakers

Objective: To evaluate the influence of hamstring extensibility on spinal and pelvic postures adopted by young paddlers in their kayaks. Methods: Sixty-eight young elite kayakers were recruited for the study (mean value 15.23, s = 0.68 years). Thoracic and lumbar curvatures and pelvic position were evaluated with a Spinal Mouse system in standing position and in the boat (seated in the kayak with the paddle resting on their thighs, right entry position and left entry position). Hamstring muscle extensibility was determined in both legs by passive straight leg raise test (PSLR). The sample was divided into two groups with regard to straight leg raise angle (Group A, PSLR < 80 degrees, n = 32, and group B, PSLR >= 80 degrees, n = 32). Results: Paddlers with lower extensibility presented higher thoracic and lumbar flexion and a more posterior pelvic tilt in the kayak in all three positions. However, no significant differences were found between the groups when standing. Conclusion: The results suggest that lower hamstring extensibility is related to increased spinal flexion and posterior pelvic tilt, which can overload the spine during paddling training. A systematic and intensive stretching programme to improve hamstring muscle extensibility should be incorporated into the training activities of paddlers.