Nordez A, Gennisson J L, Casari P, Catheline S, Cornu C
Université de Nantes, Nantes Atlantique Universités, Laboratoire "Motricité, Interactions, Performance", JE 2438, UFR STAPS, 25 bis Bd Guy Mollet, BP 72206, Nantes F-44000, France.
J Biomech. 2008 Jul 19;41(10):2305-11. doi: 10.1016/j.jbiomech.2008.03.033. Epub 2008 Jun 9.
Passive muscle stretching can be used in vivo to assess the viscoelastic properties of the entire musculo-articular complex, but does not allow the specific determination of the muscle or tendon viscoelasticity. In this respect, the local muscle hardness (LMH) of the gastrocnemius medialis (GM) belly was measured during a passive ankle stretching of 10 subjects using transient elastography. A Biodex isokinetic dynamometer was used to stretch ankle plantar flexors, to measure ankle angle, and the passive torque developed by the ankle joint in resistance to the stretch. Results show that the LMH increased during the stretching protocol, with an averaged ratio between maximal LMH and minimal LMH of 2.62+/-0.46. Furthermore, LMH-passive torque relationships were nicely fitted using a linear model with mean correlation coefficients (R(2)) of 0.828+/-0.099. A good reproducibility was found for the maximal passive torque (ICC=0.976, SEM=2.9Nm, CV=5.5%) and the y-intercept of the LMH-passive torque relationship (ICC=0.893, SEM=105Pa, CV=7.8%). However, the reproducibility was low for the slope of this relationship (ICC=0.631, SEM=10.35m(-2), CV=60.4%). The y-intercept of the LMH-passive torque relationship was not significantly changed after 10min of static stretching. This result confirms the finding of a previous study indicating that changes in passive torque following static stretching could be explained by an acute increase in muscle length without any changes in musculo-articular intrinsic mechanical properties.
被动肌肉拉伸可在体内用于评估整个肌肉-关节复合体的粘弹性特性，但无法具体测定肌肉或肌腱的粘弹性。在这方面，使用瞬态弹性成像技术对10名受试者进行被动踝关节拉伸时，测量了腓肠肌内侧头（GM）肌腹的局部肌肉硬度（LMH）。使用Biodex等速测力计拉伸踝关节跖屈肌，测量踝关节角度以及踝关节在抵抗拉伸时产生的被动扭矩。结果显示，在拉伸过程中LMH增加，最大LMH与最小LMH的平均比值为2.62±0.46。此外，使用线性模型能很好地拟合LMH-被动扭矩关系，平均相关系数（R²）为0.828±0.099。发现最大被动扭矩（ICC = 0.976，SEM = 2.9 Nm，CV = 5.5%）以及LMH-被动扭矩关系的y轴截距（ICC = 0.893，SEM = 105 Pa，CV = 7.8%）具有良好的重复性。然而，这种关系的斜率重复性较低（ICC = 0.631，SEM = 10.35 m⁻²，CV = 60.4%）。静态拉伸10分钟后，LMH-被动扭矩关系的y轴截距没有显著变化。这一结果证实了先前一项研究的发现，即静态拉伸后被动扭矩的变化可以用肌肉长度的急性增加来解释，而肌肉-关节的固有力学特性没有任何变化。
