柔韧和力量素质对疾跑中腘绳肌生物力学特征的影响：腘绳肌拉伤机制

Hamstring muscle strain injury is one of the most common and devastating injuries in sports, that has significant health and economic impact on athletes and general population participating in sports and exercise. The risk factors of this injury are still largely unknown, which made the prevention and rehabilitation of the injury difficult. Although tremendous research efforts have been made to determine if flexibility and strength are the risk factors for hamstring injury, the results, however, are inconclusive. Studies using animal models demonstrated that muscle strain injury is related to muscle strain while muscle strain is related to muscle resting length. The purposes of this study are (1) to determine the cross-sectional relationships among hamstring flexibility, strength, resting length, and maximum strain in sprinting, (2) the longitudinal relationships among hamstring flexibility, strength, resting length, and maximum strain in sprinting, and (3) the effect of hamstring flexibility and strength training on lower extremity neuromuscular control in sprinting. We will collect hamstring torque-knee angle data in maximum voluntary contractions, calculate hamstring muscle force-length relationship, and determine hamstring muscle resting length. We will also train the subjects to improve their hamstring flexibility and strength, and then determine the cause-and-effect relationships among hamstring flexibility, strength, resting length, and maximum strain in sprinting. The results of this study will provide significant information for understanding hamstring muscle strain injury, and set a concrete theoretic basis for future clinical studies to determine risk factors of muscle strain injuries.

目前尚未确定柔韧和力量素质是否与腘绳肌拉伤危险相关，因此对腘绳肌拉伤的预防和康复效果很不理想，损伤发生率居高不下，后果非常严重。动物实验已证明肌肉应变与拉伤密切相关，但由于尚缺乏测算活体腘绳肌静息长度的方法，因此仍不能确定柔韧和力量素质与腘绳肌静息长度、应变和拉伤的关系。本项目在前期研究的基础上，测算不同柔韧和力量素质受试者腘绳肌四块肌肉的静息长度，进而计算疾跑过程中腘绳肌应变，并采用国际领先的肌电驱动膝关节肌肉力分布模型计算疾跑中动态肌力，了解柔韧和力量对腘绳肌静息长度和疾跑中生物力学性质的影响。本研究还将通过训练提高受试者腘绳肌柔韧和力量素质，进一步确定柔韧和力量与腘绳肌静息长度和疾跑中肌肉应变的因果关系。本研究从纵横两个方向研究确定柔韧和力量素质是否是腘绳肌拉伤的危险因素，将为预防和康复腘绳肌拉伤和其他肌肉拉伤的临床研究奠定坚实的理论基础，为运动训练和大众体育中的损伤预防提供指导。

腘绳肌损伤在疾跑项目运动员中发生率高，后果严重，但因危险因素不明确而预防效果不佳。腘绳肌最优长度大小决定跑步时肌肉应变的大小，因此影响肌肉最优长度的因素是肌肉拉伤的危险因素。本研究从纵横两个方向确定柔韧和力量素质与腘绳肌最优长度的关系，从而分析与腘绳肌拉伤的关系。横向研究结果表明，腘绳肌的柔韧性与最优长度正相关，与疾跑时腘绳肌的峰值应变负相关，支持柔韧性是腘绳肌拉伤的危险因素；女性腘绳肌最优长度比相同柔韧性的男性短；疾跑时腘绳肌拉伤更易发生在摆动阶段末期；疾跑时腘绳肌各肌肉峰值应变的不同可能是各肌肉拉伤率不同的原因。纵向研究结果表明，柔韧或力量训练均能增加男性受试者腘绳肌最优长度，降低峰值应变，从而降低拉伤风险；柔韧和力量训练对女性受试者腘绳肌最优长度的影响有比较大的个体差异，但柔韧训练后腘绳肌峰值应变下降，因此柔韧训练可能是降低女性运动员腘绳肌拉伤风险的方法之一；柔韧和力量训练对腘绳肌最优长度和疾跑中峰值应变的影响效果与训练前的腘绳肌最优长度有关，训练前腘绳肌最优长度越短，训练影响越大。本研究结果为预防和康复腘绳肌拉伤提出明确依据，同时为其他肌肉拉伤的临床研究提供理论基础。