Objective The objective of this study is to compare the effectiveness of lower limb low-load blood flow restriction training (LL-BFRT) with high-load strength training (HL-ST) as part of an outpatient pulmonary rehabilitation programme on leg strength in patients with chronic obstructive pulmonary disease (COPD). Methods Participants were randomised to LL-BFRT or HL-ST (24 sessions). LL-BFRT was done at 30% 1-repetition maximum (1-RM) with 70% arterial occlusion pressure. HL-ST was done at 70% 1-RM. Primary outcome was isometric strength of knee extensors and flexors. Secondary outcomes were 1-RM, functional exercise capacity, physical activity, symptom burden and health-related quality of life. Perceptions of dyspnoea and leg fatigue were recorded after every exercise. We compared groups with t-tests. Results We included 30 participants (13 women, 17 men, 64 (9) years, forced expiratory volume in 1 s 47 (18)% pred.), 24 completed the study. Isometric knee extensor strength improved to a clinically relevant degree in both legs in both groups (LL-BFRT: right leg 9 (20) Nm, left leg 10 (18) Nm; HL-ST: right leg 15 (26) Nm, left leg 16 (30) Nm, data are mean (SD)), without statistically significant or clinically relevant between-group differences (right leg mean difference= −6.4, 95% CI= −13.20 to 25.92 Nm, left leg mean difference= −5.6, 95% CI= −15.44 to 26.55 Nm). 1 min sit-to-stand test performance improved to a clinically relevant degree only in the LL-BFRT group (4 (4) vs 1 (5) repetitions). Interestingly, physical activity improved to a clinically relevant degree only in the LL-BFRT group (1506 (2441) vs −182 (1971) steps/day). LL-BFRT lowered perceived in-exercise dyspnoea and increased leg fatigue compared with HL-ST in the initial 12 trainings. Conclusion In patients with stable COPD undergoing outpatient pulmonary rehabilitation, LL-BFRT was not superior to HL-ST in improving leg strength. LL-BFRT led to similar strength gains as HL-ST while reducing perceptions of dyspnoea in the initial training phase. Trial registration number [NCT04151771][1]. Data are available on reasonable request. Data generated in this study are available on reasonable request directed to the corresponding author. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT04151771&atom=%2Fthoraxjnl%2F79%2F4%2F340.atom

中文翻译：

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慢性阻塞性肺病患者的低负荷血流限制力量训练：一项随机单盲试点研究

目的 本研究的目的是比较作为门诊肺康复计划一部分的下肢低负荷血流限制训练 (LL-BFRT) 与高负荷力量训练 (HL-ST) 对患者腿部力量的有效性患有慢性阻塞性肺疾病（COPD）。方法 参与者被随机分配至 LL-BFRT 或 HL-ST（24 次）。LL-BFRT 在 30% 最大 1 次重复 (1-RM) 和 70% 动脉闭塞压力下进行。HL-ST 在 70% 1-RM 下完成。主要结果是膝关节伸肌和屈肌的等长肌力。次要结局是 1-RM、功能锻炼能力、体力活动、症状负担和健康相关的生活质量。每次锻炼后记录呼吸困难和腿部疲劳的感觉。我们通过 t 检验对各组进行比较。结果 我们纳入了 30 名参与者（13 名女性，17 名男性，64 (9) 岁，用力呼气量为 1 秒 47 (18)% 预测值），其中 24 名完成了研究。两组的双腿等长伸膝肌力均改善至临床相关程度（LL-BFRT：右腿 9 (20) Nm，左腿 10 (18) Nm；HL-ST：右腿 15 (26) Nm，左腿腿 16 (30) Nm，数据为平均值 (SD))，无统计学显着性或临床相关的组间差异（右腿平均差= -6.4，95% CI= -13.20 至 25.92 Nm，左腿平均差= - 5.6，95% CI=-15.44 至 26.55 Nm）。仅 LL-BFRT 组的 1 分钟坐站测试表现改善至临床相关程度（4 (4) 次与 1 (5) 次重复）。有趣的是，只有 LL-BFRT 组的体力活动改善到临床相关程度（1506 (2441) 步/天 vs -182 (1971) 步/天）。在最初 12 次训练中，与 HL-ST 相比，LL-BFRT 降低了运动中呼吸困难的感觉，并增加了腿部疲劳。结论 在门诊肺康复的稳定期COPD患者中，LL-BFRT在改善腿部力量方面并不优于HL-ST。LL-BFRT 带来了与 HL-ST 类似的力量增益，同时减少了初始训练阶段的呼吸困难感。试用注册号[NCT04151771][1]。可根据合理要求提供数据。本研究中生成的数据可根据合理要求向相应作者提供。[1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT04151771&atom=%2Fthoraxjnl%2F79%2F4%2F340.atom