Range of motion, neuromechanical, and architectural adaptations to plantar flexor stretch training in humans
Range of motion, neuromechanical, and architectural adaptations to plantar flexor stretch training in humans
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DOI：
10.1152/japplphysiol.00204.2014
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发表时间：
2014-09-01
影响因子：
3.3
通讯作者：
Kay, A. D.
中科院分区：
文献类型：
--
作者：
Blazevich, A. J.;Cannavan, D.;Kay, A. D.
对肌肉拉伸训练的神经肌肉适应性还没有明确的描述。在本研究中，肌肉（在束和整个肌肉水平）和肌腱力学，肌肉活动和脊髓运动神经元兴奋性的变化进行了检查，在标准化的跖屈肌拉伸3周后，每天两次拉伸训练（4 × 30秒）。在非运动对照组（n = 9）中没有观察到变化，但是拉伸训练引起背屈运动范围（ROM）增加19.9%，ROM结束时被动关节力矩增加28%（n = 12）。仅观察到牵拉过程中被动跖屈肌力矩下降的趋势（-9.9%; P = 0.15），未检测到ROM过程中或ROM结束时的肌电图振幅变化。在足底屈曲（腓肠肌内侧肌和比目鱼肌）和中性（仅比目鱼肌）关节角度观察到H-max：M-max（胫神经刺激）降低，但在踝关节背屈时未观察到。在拉伸至恒定目标关节角度期间，肌肉和肌束应变增加（12 vs. 23%）沿着，肌肉刚度降低（-18%）。在训练后，关节活动度末端的肌肉长度增加（13%），而肌束长度、肌束旋转、肌腱伸长或肌腱僵硬度没有变化。在任何关节角度下，最大随意收缩力矩和力发展速率均无变化，表明肌肉-肌腱单位的串联顺应性无变化。因此，最大可耐受被动关节力矩（拉伸耐力）以及肌肉和肌束伸长的增加，而不是意志性肌肉激活或运动神经元池兴奋性的变化，支持了末端ROM的增加。
The neuromuscular adaptations in response to muscle stretch training have not been clearly described. In the present study, changes in muscle (at fascicular and whole muscle levels) and tendon mechanics, muscle activity, and spinal motoneuron excitability were examined during standardized plantar flexor stretches after 3 wk of twice daily stretch training (4 x 30 s). No changes were observed in a nonexercising control group (n = 9), however stretch training elicited a 19.9% increase in dorsiflexion range of motion (ROM) and a 28% increase in passive joint moment at end ROM (n = 12). Only a trend toward a decrease in passive plantar flexor moment during stretch (-9.9%; P = 0.15) was observed, and no changes in electromyographic amplitudes during ROM or at end ROM were detected. Decreases in H-max:M-max (tibial nerve stimulation) were observed at plantar flexed (gastrocnemius medialis and soleus) and neutral (soleus only) joint angles, but not with the ankle dorsiflexed. Muscle and fascicle strain increased (12 vs. 23%) along with a decrease in muscle stiffness (-18%) during stretch to a constant target joint angle. Muscle length at end ROM increased (13%) without a change in fascicle length, fascicle rotation, tendon elongation, or tendon stiffness following training. A lack of change in maximum voluntary contraction moment and rate of force development at any joint angle was taken to indicate a lack of change in series compliance of the muscle-tendon unit. Thus, increases in end ROM were underpinned by increases in maximum tolerable passive joint moment (stretch tolerance) and both muscle and fascicle elongation rather than changes in volitional muscle activation or motoneuron pool excitability.