Periodized versus Non-periodized Stretch Training on Gymnasts Flexibility and Performance.

Static stretching (SS) can increase joint range of motion (ROM), due to neural, morphological, and physio-psychological factors. Periodized training programs (PD) (e. g., strength, power) are adopted to induce greater adaptations while avoiding overtraining. However, the effectiveness of periodized stretch training adaptations are unknown. Therefore, the objective of this study was to compare the effects of periodized and non-periodized (NP) stretching programs on flexibility, hamstrings stiffness and muscle performance. Sixteen gymnasts were allocated to either periodized or non-periodized SS training and tested pre- and post-8 weeks for countermovement jump height, hip flexors, hip extensors and dorsiflexors ROM, hamstrings stiffness and hamstrings and quadriceps peak torque. Both stretch training groups significantly and similarly increased hip extensor (33.2%), hip flexor (25.2%), and dorsiflexor (23.8%) ROM, hamstrings peak torque (7.9%) and jump height (8.1%) from pre - to post- training. Both groups decreased hamstrings stiffness across the last ten angles (32.1%). PD elicited consistently large magnitude flexibility effect size changes compared to small and moderate magnitude changes for the non-periodized. Therefore, 8-week PD and NP SS programs can decrease young gymnasts' muscle-tendon stiffness and increase muscle performance. However, effect sizes indicate that PD stretch training was more advantageous to increasing flexibility and improving performance.