Chronic effects of muscle and nerve-directed stretching on tissue mechanics
Chronic effects of muscle and nerve-directed stretching on tissue mechanics
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DOI：
10.1152/japplphysiol.00239.2019
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发表时间：
2020-11-01
影响因子：
3.3
通讯作者：
Nordez, Antoine
中科院分区：
文献类型：
--
作者：
Andrade, Ricardo J.;Freitas, Sandro R.;Nordez, Antoine
组织定向拉伸干预可以优先加载肌肉或非肌肉结构，如周围神经。人们对这些组织如何机械地适应长期拉伸知之甚少。这项随机、单盲、对照研究使用超声和测力技术比较了12周神经和肌肉牵拉训练方案与对照组对小腿三头肌和坐骨神经的最大踝关节背屈活动范围(ROM)和被动扭矩、剪切波速度(SWV；僵硬指数)和结构的影响。60名健康成年人被随机分为神经定向拉伸和肌肉定向拉伸两组。或不干预(对照)。肌肉导向的方案主要是伸展足底屈肌群，而神经导向的干预主要针对坐骨神经束。与对照组比较[平均值；95%可信区间(CI)]。肌肉定向干预表现为活动度增加(+7.3°；95%CI：4.1~10.5)，小腿三头肌SWV降低(-0.8~-2.3m/S)，被动扭矩减少(-6.8 N.M；95%CI：-11.9~-1.7)，腓肠肌内侧肌束长(+0.4 cm；95%CI：0.1~0.8)。肌肉定向干预不影响坐骨神经的SWV和大小。与对照组相比，神经导向组受试者的活动度显著增加(+9.9度；95%可信区间：6.2~13.6)，坐骨神经SWV(跨神经区)显著降低(>；-1.8m/S)。神经定向干预对肌肉和关节水平的主要结果没有影响。这些发现为拉伸干预的长期力学效应提供了新的见解，并与发生力学特性变化的临床条件相关。新和值得注意的是，这项研究证明，足底屈肌和坐骨神经的力学特性可以机械地适应长期拉伸计划。尽管针对肌肉或非肌肉结构的干预在增加最大活动范围方面都是有效的，但组织机械特性(硬度)的变化是由每个方案优先拉伸的结构特有的。我们提供了第一个活体证据，表明周围神经的僵硬通过适当的神经定向伸展来适应长期的负荷刺激。
Tissue-directed stretching interventions can preferentially load muscular or nonmuscular structures such as peripheral nerves. How these tissues adapt mechanically to long-term stretching is poorly understood. This randomized, single-blind, controlled study used ultrasonography and dynamometry to compare the effects of 12-wk nerve-directed and muscle-directed stretching programs versus control on maximal ankle dorsiflexion range of motion (ROM) and passive torque, shear wave velocity (SWV; an index of stiffness), and architecture of triceps surae and sciatic nerve. Sixty healthy adults were randomized to receive nerve-directed stretching, muscle-directed stretching. or no intervention (control). The muscle-directed protocol was designed to primarily stretch the plantar flexor muscle group, whereas the nerve-directed intervention targeted the sciatic nerve tract. Compared with the control group [mean; 95% confidence interval (CI)]. muscle-directed intervention showed increased ROM (+7.3 degrees; 95% CI: 4.1-10.5), decreased SWV of triceps surae (varied from -0.8 to -2.3 m/s across muscles), decreased passive torque ( -6.8 N.m; 95% CI: -11.9 to -1.7), and greater gastrocnemius medialis fascicle length (+0.4 cm; 95% CI: 0.1-0.8). Muscle-directed intervention did not affect the SWV and size of sciatic nerve. Participants in the nerve-directed group showed a significant increase in ROM (+9.9 degrees ; 95% CI: 6.2-13.6) and a significant decrease in sciatic nerve SWV (> -1.8 m/s across nerve regions) compared with the control group. Nerve-directed intervention had no effect on the main outcomes at muscle and joint levels. These findings provide new insights into the long-term mechanical effects of stretching interventions and have relevance to clinical conditions where change in mechanical properties has occurred.NEW & NOTEWORTHY This study demonstrates that the mechanical properties of plantar flexor muscles and sciatic nerve can adapt mechanically to long-term stretching programs. Although interventions targeting muscular or nonmuscular structures are both effective at increasing maximal range of motion, the changes in tissue mechanical properties (stiffness) arc specific to the structure being preferentially stretched by each program. We provide the first in vivo evidence that stiffness of peripheral nerves adapts to long-term loading stimuli using appropriate nerve-directed stretching.