Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON, L2S 3A1, Canada.
Centre for Bone and Muscle Health, Faculty of Applied Health Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON, Canada.
Eur J Appl Physiol. 2021 Aug;121(8):2177-2185. doi: 10.1007/s00421-021-04687-4. Epub 2021 Apr 17.
In adults, low-load resistance training with blood flow occlusion (BFO) mimics strength increases that occur from high-load training, without the need to experience high mechanical stress. In view of child-adult differences in exercise responses, this study examined whether BFO during exercise elicits differential changes in maximal voluntary contraction (MVC) and electromyographical (EMG) activity in children and adults.
Sixteen men (24.4 ± 2.5 years) and 14 boys (10.7 ± 2.0 years) performed low-load resistance exercise (25 repetitions at 35% MVC) of the wrist flexors with and without BFO. MVC wrist flexor force and EMG activity of the flexor carpi radialis (FCR) were obtained at the beginning and end of the exercise.
Both groups demonstrated a larger decrease in MVC force following BFO (- 18.6 ± 12.5%) than the control (without BFO) condition (- 6.2 ± 15.0%; p < 0.001). Whereas the men's EMG amplitude increased 16.3 ± 20.5% (p = 0.005) during BFO, the boys' EMG amplitude did not change over time or between conditions. In both groups, the mean power frequency (MPF) of the EMG signal decreased more during BFO (- 20.1 ± 9.6%; p < 0.001) than the control condition (- 5.6 ± 9.7%; p = 0.002).
Low-load exercise with BFO resulted in similar neuromuscular responses between boys and men, except for an observed increase in the EMG amplitude in men but not boys. While this result might suggest that men relied on a greater activation of higher-threshold motor units during BFO, it does not explain why there were similar decreases in MPF between groups. Therefore, it remains unclear whether the effectiveness of BFO training is similar for children and adults.
在成年人中，使用血流阻断（BFO）的低负荷阻力训练可以模拟高负荷训练引起的力量增加，而无需承受高机械应力。鉴于儿童和成人在运动反应方面的差异，本研究旨在探讨在儿童和成人中，运动时使用 BFO 是否会引起最大自主收缩（MVC）和肌电图（EMG）活动的差异变化。
16 名男性（24.4±2.5 岁）和 14 名男孩（10.7±2.0 岁）进行了腕屈肌的低负荷阻力运动（25 次重复，35% MVC），并分别在有和没有 BFO 的情况下进行。在运动开始和结束时，获得了腕屈肌的 MVC 力和屈腕肌（FCR）的 EMG 活动。
两组在 BFO 后（-18.6±12.5%）的 MVC 力下降均大于对照组（无 BFO）（-6.2±15.0%；p<0.001）。虽然男性的 EMG 幅度在 BFO 期间增加了 16.3±20.5%（p=0.005），但男孩的 EMG 幅度在不同时间或不同条件下均未发生变化。在两组中，EMG 信号的平均功率频率（MPF）在 BFO 期间下降更多（-20.1±9.6%；p<0.001），而在对照组中下降更少（-5.6±9.7%；p=0.002）。
使用 BFO 的低负荷运动在男孩和男性之间产生了相似的神经肌肉反应，除了男性的 EMG 幅度增加而男孩没有增加之外。虽然这一结果可能表明男性在 BFO 期间依赖更高阈值运动单位的更大激活，但它并不能解释为什么两组之间的 MPF 下降相似。因此，尚不清楚 BFO 训练对儿童和成人的有效性是否相似。
