Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia.
Department of Health and Medical Sciences, Faculty of Health, Arts and Design, Swinburne University of Technology, Hawthorn, Vic., Australia.
Scand J Med Sci Sports. 2021 Jun;31(6):1290-1300. doi: 10.1111/sms.13936. Epub 2021 Mar 3.
We tested the hypothesis that the magnitude of changes in indirect muscle damage markers would be greater after maximal elbow flexor eccentric exercise in the supinated (shorter biceps brachii) than neutral wrist (longer) position, and the difference in the magnitude would be associated with greater elongation over contractions for the supinated than neutral position, rather than the initial muscle length. Ten untrained men (21-39 years) performed two bouts of 10 sets of 6 maximal isokinetic eccentric contractions of the elbow flexors in the supinated position for one arm and neutral position for the other arm separated by 2 weeks in a randomized order. Biceps brachii myotendinous junction (MTJ) movements during eccentric contractions were recorded by B-mode ultrasonography, and the displacement from the start to end of each contraction was quantified. Peak torque (supinated: 367.8 ± 112.5 Nm, neutral: 381.5 ± 120.4 Nm) and total work (1816 ± 539 J, 1865 ± 673 J) produced during eccentric contractions were similar between conditions. The average MTJ displacement increased (P < .05) from the 1st set (8.0 ± 2.0 mm) to 10th set (15.8 ± 1.9 mm) for the supinated condition, but no such increase was found in the neutral condition (1st set: 5.1 ± 1.0 mm, 10th set: 5.0 ± 0.8 mm). Changes in indirect muscle damage markers (maximal voluntary isometric contraction torque, range of motion, serum creatine kinase activity, and muscle soreness) after exercise were greater (P < .05) for the supinated than neutral condition. These results suggest that the greater muscle damage marker changes for the supinated than neutral wrist position was associated with the greater muscle lengthening (strain).
我们验证了一个假设，即在旋前（较短的肱二头肌）而非中立（较长）腕部位置进行最大肘伸肌离心运动后，间接肌肉损伤标志物的变化幅度会更大，并且这种差异与旋前位置比中立位置的更大收缩相比，与初始肌肉长度无关。10 名未经训练的男性（21-39 岁）以随机顺序在 2 周内分别进行了两次 10 组 6 次最大等速离心肘伸肌运动，一组在旋前位置，另一组在中立位置。通过 B 型超声记录离心收缩过程中肱二头肌肌腹肌腱连接处（MTJ）的运动，量化每个收缩的起点到终点的位移。离心收缩时的峰值扭矩（旋前：367.8±112.5 Nm，中立：381.5±120.4 Nm）和总功（1816±539 J，1865±673 J）在两种情况下相似。旋前条件下，MTJ 位移从第 1 组（8.0±2.0 mm）增加到第 10 组（15.8±1.9 mm）（P<.05），但在中立条件下没有发现这种增加（第 1 组：5.1±1.0 mm，第 10 组：5.0±0.8 mm）。运动后间接肌肉损伤标志物（最大自主等长收缩扭矩、运动范围、血清肌酸激酶活性和肌肉酸痛）的变化在旋前位置比中立位置更大（P<.05）。这些结果表明，旋前位置比中立腕部位置更大的肌肉损伤标志物变化与更大的肌肉拉伸（应变）有关。
