The architecture of the biceps femoris (BF) and stiffness of the hamstrings have been found to be associated with injury risk. However, less is known about the architecture of the equally voluminous semitendinosus (ST) and viscoelastic properties of both muscles in individuals with a prior injury. Methods: BF and ST of 15 athletes (previously injured, [Formula: see text]; control, [Formula: see text]) were assessed using ultrasonography and myotonometry. Mean architecture (muscle thickness (MT), pennation angle (PA) and fascicle length (FL)) and viscoelastic measures (stiffness, oscillation frequency and decrement) were compared between the previously injured and contralateral uninjured limb, and between the previously injured and control limbs (mean of both limbs of the control group). Control group participants returned for a duplicate measurement. Findings: Both muscles exhibited high reliability between sessions (intraclass correlation coefficient [Formula: see text]) for architecture. BF PA was larger in the previously injured than both uninjured [Formula: see text] and control [Formula: see text]. BF fascicles were shorter in the previously injured limb compared to the uninjured [Formula: see text] and control [Formula: see text]. BF was stiffer in the previously injured compared to uninjured [Formula: see text]. ST architecture and viscoelasticity were similar across limbs. Conclusion: A prior hamstring strain injury is associated with a stiffer BF characterized by larger PAs and shorter fascicles.

中文翻译：

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腘绳肌结构和粘弹性：既往受伤运动员和未受伤运动员之间的可靠性和回顾性比较

已发现股二头肌 (BF) 的结构和腘绳肌的刚度与受伤风险有关。然而，对于先前受伤的个体中同样体积的半腱肌 (ST) 的结构和两块肌肉的粘弹性特性知之甚少。方法：使用超声和肌张力测量法评估 15 名运动员（既往受伤，[公式：见正文]；对照组，[公式：见正文]）的 BF 和 ST。比较先前受伤肢体和对侧未受伤肢体以及先前受伤肢体和对照组之间的平均结构（肌肉厚度 (MT)、羽状角 (PA) 和肌束长度 (FL)）和粘弹性测量值（刚度、振荡频率和减量）四肢（对照组双肢的平均值）。对照组参与者返回进行重复测量。结果：两块肌肉在建筑的会话之间表现出高可靠性（类内相关系数[公式：见正文]）。先前受伤的BF PA大于未受伤的[公式：见文本]和对照[公式：见文本]。与未受伤的[公式：见文本]和对照[公式：见文本]相比，先前受伤肢体的 BF 束更短。与未受伤的相比，先前受伤的 BF 更僵硬 [公式：见正文]。ST 结构和粘弹性在四肢相似。结论：先前的腘绳肌劳损与较硬的 BF 相关，其特征是较大的 PA 和较短的肌束。见正文]) 用于建筑。先前受伤的BF PA大于未受伤的[公式：见文本]和对照[公式：见文本]。与未受伤的[公式：见文本]和对照[公式：见文本]相比，先前受伤肢体的 BF 束更短。与未受伤的相比，先前受伤的 BF 更僵硬 [公式：见正文]。ST 结构和粘弹性在四肢相似。结论：先前的腘绳肌劳损与较硬的 BF 相关，其特征是较大的 PA 和较短的肌束。见正文]) 用于建筑。先前受伤的BF PA大于未受伤的[公式：见文本]和对照[公式：见文本]。与未受伤的[公式：见文本]和对照[公式：见文本]相比，先前受伤肢体的 BF 束更短。与未受伤的相比，先前受伤的 BF 更僵硬 [公式：见正文]。ST 结构和粘弹性在四肢相似。结论：先前的腘绳肌劳损与较硬的 BF 相关，其特征是较大的 PA 和较短的肌束。与未受伤的相比，先前受伤的 BF 更僵硬 [公式：见正文]。ST 结构和粘弹性在四肢相似。结论：先前的腘绳肌劳损与较硬的 BF 相关，其特征是较大的 PA 和较短的肌束。与未受伤的相比，先前受伤的 BF 更僵硬 [公式：见正文]。ST 结构和粘弹性在四肢相似。结论：先前的腘绳肌劳损与较硬的 BF 相关，其特征是较大的 PA 和较短的肌束。