PDF(Pubmed)
Abstract：
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.
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.
摘要：
背景：血流限制（BFR）阻力训练已证明在促进有利于康复的力量增加方面具有功效。然而，使用高负荷和低负荷方案进行BFR力量训练的明显功能优势尚不清楚.这项研究探索了行为和神经生理机制，这些机制可以解释容量匹配的高负荷和低负荷BFR训练后的不同影响。
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。他们接受了为期3周的BFR训练，以最大自愿收缩（MVC）的25％或75％的强度进行等距腕部伸展，并具有匹配的训练量。前后测试包括MVC和梯形力跟踪测试（0-75％-0％MVC）以及来自指伸肌的多通道表面肌电图（EMG）。
结果：训练后，BFR-HL组比BFR-LL组表现出更大的力量增长（BFR_HL：26.96±16.33％vs.BFR_LL:11.16±15.34%)(p=0.020)。然而,只有BFR-LL组在后验跟踪性能的力稳定性方面有所改善(p=0.004)，与BFR-HL组相比，力波动的归一化变化较小（p=0.048）。培训后,BFR-HL组激活的运动单位（MU）具有较高的募集阈值（p<0.001）和较长的尖峰间隔（p=0.002），与BFR-LL组相反，在力跟踪过程中，激活的MU具有较低的募集阈值（p<0.001）和较短的尖峰间隔（p<0.001）。两组训练后，MU的出院变异性（p<0.003）和共同驱动指数（p<0.002）均持续降低。
结论：BFR-HL训练导致更大的力量增益，而BFR-LL训练更好地改善了力的精度控制，这是由于激活了具有较低的募集阈值和较高的出院率的MU。
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。他们接受了为期3周的BFR训练，以最大自愿收缩（MVC）的25％或75％的强度进行等距腕部伸展，并具有匹配的训练量。前后测试包括MVC和梯形力跟踪测试（0-75％-0％MVC）以及来自指伸肌的多通道表面肌电图（EMG）。
结果：训练后，BFR-HL组比BFR-LL组表现出更大的力量增长（BFR_HL：26.96±16.33％vs.BFR_LL:11.16±15.34%)(p=0.020)。然而,只有BFR-LL组在后验跟踪性能的力稳定性方面有所改善(p=0.004)，与BFR-HL组相比，力波动的归一化变化较小（p=0.048）。培训后,BFR-HL组激活的运动单位（MU）具有较高的募集阈值（p<0.001）和较长的尖峰间隔（p=0.002），与BFR-LL组相反，在力跟踪过程中，激活的MU具有较低的募集阈值（p<0.001）和较短的尖峰间隔（p<0.001）。两组训练后，MU的出院变异性（p<0.003）和共同驱动指数（p<0.002）均持续降低。
结论：BFR-HL训练导致更大的力量增益，而BFR-LL训练更好地改善了力的精度控制，这是由于激活了具有较低的募集阈值和较高的出院率的MU。
