Background: Previous research demonstrates hamstring muscle-tendon stiffness (HMTS) influences isometric strength, landing biomechanics and architectural tissue properties. However, the influence on kinetics & kinematics during other modes of strength testing (isotonic dynamometry) has yet to be established. Purpose: Investigate how HMTS influences kinetics and kinematics during a novel isotonic muscle performance test which has never been done for the hamstrings. Previous work using dynamometry has been limited to isometric or isokinetic contractions, so the novelty arises from our custom isotonic protocol which allows quantitative assessment of the stretch-shortening cycle. Methods: Twenty-six recreationally active individuals (15 males, 11 females, 23.8 ± 2.5 yrs.) completed baseline testing for anthropometry and maximum isometric hamstring strength (MVIC). At least 48 h later, subjects completed a measure of HMTS (damped oscillation technique) followed by an isotonic knee flexion test (eccentric velocity 180°/s; concentric torque 25% of MVIC). Separate linear regression models with examination of residuals were conducted between HMTS and each muscle performance variable. Standardized coefficients determined the magnitude of the relationships. Results: Significance was found for all outcome variables tested. HMTS and rate of torque development demonstrated the strongest relationship followed by isotonic concentric peak torque. The weakest relationship observed was with isometric peak torque. Conclusions: These findings build off previous work quantifying HMTS by showing HMTS more strongly relates to dynamic versus static muscle testing and identifies the potential clinical utility of isotonic dynamometry.

中文翻译：

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主动Ham绳肌僵硬度对等张肌性能指标的影响

背景：先前的研究表明，绳肌肌腱刚度（HMTS）影响等距强度，着陆生物力学和建筑组织特性。但是，尚未确定其他强度测试模式（等渗测功）对动力学和运动学的影响。目的：在从未进行过的ham绳肌等腰肌新功能测试中，研究HMTS如何影响动力学和运动学。以前使用测力计的工作仅限于等距或等速收缩，因此新颖性源自我们的自定义等渗方案，该方案允许对拉伸缩短周期进行定量评估。方法：二十六个娱乐活动个体（男15例，女11例，23.8±2.5岁）。）完成了人体测量学和最大等距腿筋强度（MVIC）的基线测试。至少48小时后，受试者完成了HMTS（阻尼振荡技术）的测量，随后进行了等张膝盖屈曲试验（偏心速度180°/ s；同心扭矩为MVIC的25％）。在HMTS和每个肌肉性能变量之间进行了单独的线性回归模型，并检验了残差。标准化系数确定了关系的大小。结果：发现所有测试结果变量的意义。HMTS和扭矩发展速度表现出最强的关系，其次是等渗同心峰值扭矩。观察到的最弱的关系是与等距峰值扭矩。结论：