Differential changes in muscle architecture and neuromuscular fatigability induced by isometric resistance training at short and long muscle-tendon unit lengths
Differential changes in muscle architecture and neuromuscular fatigability induced by isometric resistance training at short and long muscle-tendon unit lengths
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DOI：
10.1152/japplphysiol.00280.2020
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发表时间：
2020-07-01
影响因子：
3.3
通讯作者：
Power, Geoffrey A.
中科院分区：
文献类型：
--
作者：
Akagi, Ryota;Hinks, Avery;Power, Geoffrey A.
我们评估了不同的肌肉结构适应对神经肌肉抗疲劳性的影响。七名年轻男性和六名女性参与了这项研究。采用纵向受试者内设计，将腿部随机分配为每周进行三次胫骨前肌（TA）等长训练，持续8周，肌肉肌腱单位长度较短（S组）或较长（L组）。在训练前和训练后，测量TA的束长（FL）和羽状角（PA）。以及，疲劳相关的时间过程中的变化，等距最大自主收缩（MVC）扭矩和等张峰值功率（20%MVC阻力）之前，之后立即，1，2，5，和10分钟后任务失败。疲劳任务包括在40度运动范围内重复最大努力等张（20%MVC阻力）收缩，直到参与者达到峰值功率降低40%。尽管两组在训练后神经肌肉疲劳抵抗力都没有明显的改善，（P = 0.081; S组：与20%相似; L组：与51%相似），神经肌肉疲劳抗力的变化与训练引起的PA增加呈正相关L-组与训练诱导的FL增加呈负相关（r =-0.568，P = 0.043）。两组在疲劳任务后与训练前相比，MVC扭矩和峰值功率恢复相似。我们认为，肌肉结构的变化和神经肌肉疲劳抗力之间的关系取决于在其中的肌肉肌腱单位长度的trainingisperformed.NEW & NOTEWORTH 8周的等距训练在长或短的肌肉肌腱单位长度增加，并没有改变束长度。长距离等长训练后，扭矩-角度关系平台的“宽度”变宽。尽管两组之间的肌肉结构和功能适应性存在显着差异，但神经肌肉疲劳抗性只有小幅改善，这与长距离训练组中的肌束长度增加呈负相关。
We evaluated the effects of differential muscle architectural adaptations on neuromuscular fatigue resistance. Seven young males and six females participated in this study. Using a longitudinal within-subject design, legs were randomly assigned to perform isometric training of the tibialis anterior (TA) three times per week for 8 wk at a short (S-group) or long muscle-tendon unit length (L-group). Before and following training, fascicle length (FL) and pennation angle (PA) of the TA were assessed. As well, fatigue-related time course changes in isometric maximal voluntary contraction (MVC) torque and isotonic peak power (20% MVC resistance) were determined before, immediately after, and 1, 2, 5, and 10 min following task failure. The fatiguing task consisted of repeated maximal effort isotonic (20% MVC resistance) contractions over a 40 degrees range of motion until the participant reached a 40% reduction in peak power. Although there was no clear improvement in neuromuscular fatigue resistance following training in either group (P = 0.081; S-group: similar to 20%; L-group: similar to 51%), the change in neuromuscular fatigue resistance was related positively to the training-induced increase in PA (similar to 6%, P < 0.001) in the S-group (r = 0.739, P = 0.004) and negatively to the training-induced increase in FL (similar to 4%, P = 0.001) in the L-group (r = -0.568, P = 0.043). Both groups recovered similarly for MVC torque and peak power after the fatiguing task as compared with before training. We suggest that the relationships between the changes in muscle architecture and neuromuscular fatigue resistance depend on the muscle-tendon unit lengths at which the training is performed.NEW & NOTEWORTHY Eight weeks of isometric training at a long or short muscle-tendon unit length increased and did not change fascicle length, respectively. The "width" of the torque-angle relationship plateau became broader following isometric training at the long length. Despite marked differences in muscle architecture and functional adaptations between the groups, there was only a small-magnitude improvement in neuromuscular fatigue resistance, which was surprisingly negatively related to increased fascicle length in the long length-training group.