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.

IF 5.2 2区 医学 Q1 ENGINEERING, BIOMEDICAL
Yen-Ting Lin, Chun-Man Wong, Yi-Ching Chen, Yueh Chen, Ing-Shiou Hwang
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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.

在容量匹配条件下进行高负荷和低负荷血流限制运动后,腕力精确任务的训练效益和运动单元重塑存在差异。
背景:血流限制(BFR)阻力训练已被证明能有效提高力量,有利于康复。然而,使用高负荷和低负荷方案进行 BFR 力量训练的不同功能优势仍不清楚。本研究探讨了行为和神经生理学机制,以解释高负荷和低负荷血流阻力训练后的不同效果:28名健康参与者被随机分配到高负荷血流限制组(BFR-HL,n = 14)和低负荷血流限制组(BFR-LL,n = 14)。他们接受了为期 3 周的 BFR 训练,训练强度为最大自主收缩(MVC)的 25% 或 75%,训练量相匹配,进行腕关节等长伸展训练。前后测试包括 MVC 和梯形力跟踪测试(0-75%-0% MVC),以及多通道拇伸肌表面肌电图(EMG):结果:训练后,BFR-HL 组比 BFR-LL 组显示出更大的力量增长(BFR_HL:26.96 ± 16.33% vs. BFR_LL:11.16 ± 15.34%)(p = 0.020)。然而,与 BFR-HL 组相比(p = 0.048),只有 BFR-LL 组的力量波动归一化变化较小(p = 0.004),表明 BFR-LL 组在后测试中跟踪性能的力量稳定性有所改善。训练后,BFR-HL 组激活的运动单元(MU)具有更高的募集阈值(p 结论:BFR-HL 组激活的运动单元(MU)具有更高的募集阈值(p = 0.004):BFR-HL训练使力量获得了更大的提高,而BFR-LL训练由于激活了具有较低募集阈值和较高放电率的运动单元,更好地改善了力量精确控制。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Journal of NeuroEngineering and Rehabilitation
Journal of NeuroEngineering and Rehabilitation 工程技术-工程:生物医学
CiteScore
9.60
自引率
3.90%
发文量
122
审稿时长
24 months
期刊介绍: Journal of NeuroEngineering and Rehabilitation considers manuscripts on all aspects of research that result from cross-fertilization of the fields of neuroscience, biomedical engineering, and physical medicine & rehabilitation.
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