Effects of dynamic stretching of different duration on lower limb flexibility in male sport dancers: A randomized controlled trial
Authors: Wang Jingzhen , Hu Fang , Qiu Xuan , Li Han 
Published: January 2025

In the field of sports training and teaching, stretching is regarded as a highly valuable technique, particularly in its capacity to facilitate gradual acclimatization of the body to the exercise state during the warm-up session and as a means of enhancing flexibility qualities. As the research on athletic training continues to deepen, the discussion on the respective advantages of static stretching and dynamic stretching is becoming increasingly prominent. In this study, dynamic stretching was selected as the primary intervention to investigate the effects of varying durations of dynamic stretching on the flexibility of the legs of male students majoring in sport dance, with a particular focus on the underlying biomechanical mechanisms. Method: The subjects were 40 male first- and second-year students majoring in physical education dance at Yichun College, randomly assigned to one of four groups of 10 students each. The methodology comprised a dynamic stretching warm-up and quality training prior to the commencement of regular sports dance teaching, after which the basic teaching session was initiated. The study employed SPSS 22.0 software to conduct a T-test to analyze the effects of different stretching durations on flexibility. SPSS 22.0 software was utilized to perform a T-test. Biomechanical parameters such as muscle fiber recruitment patterns, joint range of motion, and force generation during stretching were also measured and analyzed. Results: (1) Dynamic stretching in warm-ups and training can boost lower limb flexibility. Biomechanically, this is attributed to the activation of specific muscle groups and the modulation of connective tissue properties. A significant difference observed between dominant and non-dominant limbs, which may be related to differences in neuromuscular control and muscle fiber composition. (2) A 20-minute stretch in warm-ups and a 30-minute stretch in training were best for flexibility, showing a more pronounced effect on the dominant side. This could be due to the dominant limb's greater ability to generate force and adapt to biomechanical stress, as well as its more efficient neuromuscular coordination. (3) The right side, which corresponds to the dominant limb in most subjects, improved more than the left with dynamic stretching. This could be attributed to the greater neural activation and muscle recruitment efficiency, which are key biomechanical factors in the stretching response. (4) Although dynamic stretching is slower than static stretching in enhancing flexibility, consistent sessions exceeding 20 minutes can still yield positive results for both limbs though the dominant limb may benefit more initially., likely due to its pre-existing biomechanical advantages and more refined neuromuscular pathways. Conclusion: Dynamic stretching effectively improves lower limb flexibility, though more slowly than static stretching. Regular sessions over 20 min, especially 20-minute warm-ups and 30-minute training, can notably enhance flexibility, with a significant impact on the dominant limb, suggesting that while non-dominant limbs also benefit, the dominant limb may require less time to achieve similar flexibility improvements due to its inherent biomechanical and neuromuscular characteristics.