在体积匹配条件下，高、低负荷血流限制训练后，手腕力精准任务中的差异训练效益和运动单位重塑。
Differential training benefits and motor unit remodeling in wrist force precision tasks following high and low load blood flow restriction exercises under volume-matched conditions.
机构信息
Department of Ball Sport, National Taiwan University of Sport, Taichung City, Taiwan.
Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan City, Taiwan.
出版信息
J Neuroeng Rehabil. 2024 Jul 19;21(1):123. doi: 10.1186/s12984-024-01419-5.
BACKGROUND
Blood flow restriction (BFR) resistance training has demonstrated efficacy in promoting strength gains beneficial for rehabilitation. Yet, the distinct functional advantages of BFR strength training using high-load and low-load protocols remain unclear. This study explored the behavioral and neurophysiological mechanisms that explain the differing effects after volume-matched high-load and low-load BFR training.
METHODS
Twenty-eight healthy participants were randomly assigned to the high-load blood flow restriction (BFR-HL, n = 14) and low-load blood flow restriction (BFR-LL, n = 14) groups. They underwent 3 weeks of BFR training for isometric wrist extension at intensities of 25% or 75% of maximal voluntary contraction (MVC) with matched training volume. Pre- and post-tests included MVC and trapezoidal force-tracking tests (0-75%-0% MVC) with multi-channel surface electromyography (EMG) from the extensor digitorum.
RESULTS
The BFR-HL group exhibited a greater strength gain than that of the BFR-LL group after training (BFR_HL: 26.96 ± 16.33% vs. BFR_LL: 11.16 ± 15.34%)(p = 0.020). However, only the BFR-LL group showed improvement in force steadiness for tracking performance in the post-test (p = 0.004), indicated by a smaller normalized change in force fluctuations compared to the BFR-HL group (p = 0.048). After training, the BFR-HL group activated motor units (MUs) with higher recruitment thresholds (p < 0.001) and longer inter-spike intervals (p = 0.002), contrary to the BFR-LL group, who activated MUs with lower recruitment thresholds (p < 0.001) and shorter inter-spike intervals (p < 0.001) during force-tracking. The discharge variability (p < 0.003) and common drive index (p < 0.002) of MUs were consistently reduced with training for the two groups.
CONCLUSIONS
BFR-HL training led to greater strength gains, while BFR-LL training better improved force precision control due to activation of MUs with lower recruitment thresholds and higher discharge rates.
背景
血流限制（BFR）抗阻训练已被证明能有效促进有益于康复的力量增长。然而，高负荷和低负荷 BFR 强度训练的独特功能优势仍不清楚。本研究探讨了解释高负荷和低负荷 BFR 训练后效果不同的行为和神经生理机制。
方法
将 28 名健康参与者随机分配到高负荷血流限制（BFR-HL，n=14）和低负荷血流限制（BFR-LL，n=14）组。他们在 3 周的时间内进行等长腕伸肌的 BFR 训练，强度分别为最大自主收缩（MVC）的 25%或 75%，并进行匹配的训练量。预测试和后测试包括 MVC 和梯形力跟踪测试（0-75%-0% MVC），同时对伸指肌进行多通道表面肌电图（EMG）。
结果
训练后，BFR-HL 组的力量增长大于 BFR-LL 组（BFR_HL：26.96±16.33% vs. BFR_LL：11.16±15.34%）（p=0.020）。然而，只有 BFR-LL 组在跟踪测试中显示出力量稳定性的改善（p=0.004），这表现为与 BFR-HL 组相比，力波动的归一化变化较小（p=0.048）。训练后，BFR-HL 组激活了具有较高募集阈值的运动单位（MUs）（p<0.001）和较长的肌电脉冲间隔（p=0.002），而 BFR-LL 组则激活了具有较低募集阈值（p<0.001）和较短肌电脉冲间隔（p<0.001）的 MUs。两组的 MU 放电变异性（p<0.003）和共同驱动指数（p<0.002）在训练后均持续降低。
结论
BFR-HL 训练导致更大的力量增长，而 BFR-LL 训练由于激活了募集阈值较低和放电率较高的 MU，更好地改善了力精度控制。
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