長、短距離選手於捷泳200公尺之軀幹旋轉對稱性與上下肢動力鏈傳遞

Purpose: To evaluate the symmetry of the core muscle activation and the relation between core muscle activation and stroke length and stroke rates during front crawl. Methods: Eight male long-distance swimmers and ten male short-distance swimmers were recruited. Wireless Inertial Measurement Units were used to collect kinematic parameters to define the swimming motion cycle. Synchronized camera was used to record the swimming movements on the preferred side, and waterproof wireless surface electromyography device was used to measure the muscle activation. Mixed two-way analysis of variance was employed to analyze differences in stroke frequency, shoulder roll angles, kicking frequency, muscle activation of twelve muscles, and the medial frequency of each muscles. Intra-group analysis was conducted the difference among each 50-meter segments, and inter-group analysis was compared the difference between the long-distance and short-distance swimmers. Results: During the 200-meter sprint, all swimmers tended to use a higher stroke frequency in the first segment than other 3 segments. In kicking frequency, all swimmers exhibited higher frequencies in the first segment, but the long-distance swimmers maintained higher stroking frequencies throughout the entire race. Higher activations of upper limb muscles were noted, while no significant differences of trunk muscles were found between long-distance and short-distance swimmers. Conclusion: For all swimmers, the pectoralis major and latissimus dorsi were considered the main propulsive muscles, and the trunk muscles were used as the stabilizer in swimming. Long-distance swimmers demonstrated more stable speed during swimming and maintained a higher stroking frequency to accelerate in the later stages of the race.