Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University , Umeå, Sweden.
Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Quebec, Canada.
Sci Rep. 2021 Jun 2;11(1):11557. doi: 10.1038/s41598-021-90758-7.
Knowledge about modifiable determinants of daily physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) is crucial to design effective PA interventions. The present study aimed to determine the contribution of quadriceps strength, power and endurance to daily PA in COPD. Additionally, for quadriceps endurance, we also aimed to determine to what extent the association varies according to the mode of movement (isotonic, isometric, or isokinetic). Using a multicentre cross-sectional trial design we determined the contribution of quadriceps function to daily PA (steps, sedentary time and time spent doing moderate-to-very-vigorous physical activity [MVPA]) using bivariate and partial Pearson correlation analysis (r) and multiple linear regression models (ΔR). Pre-determined controlling factors were sex, age, body mass index (BMI), COPD-assessment test, forced expiratory volume in one second in percent of the predicted value (FEV), and distance walked on the 6-minute walk test. Eighty-one patients with COPD (mean ± SD: age 67 ± 8 years, FEV 57 ± 19%, daily steps 4968 ± 3319, daily sedentary time 1016 ± 305 min, and MVPA time 83 ± 45 min) were included. Small to moderate bivariate correlations (r = .225 to .452, p < .05) were found between quadriceps function and measures of PA. The best multiple linear regression models explained 38-49% of the variance in the data. Isotonic endurance was the only muscle contributor that improved all PA models; daily steps (ΔR = .04 [relative improvement 13%] p = .026), daily sedentary time (ΔR = .07 [23%], p = .005) and MVPA-minutes (ΔR = .08 [20%], p = .001). Isotonic endurance was also independently associated with most PA variables, even when controlling for strength, power or isometric-isokinetic endurance properties of the muscle (r = .246 to .384, p < .05). In contrast, neither strength, power, isometric-or isokinetic endurance properties of the muscle was independently associated with PA measures when controlling for isotonic endurance (r = .037 to .219, p > .05). To conclude, strength, power, and endurance properties of the quadriceps were low to moderately associated with PA in patients with COPD. Isotonic quadriceps endurance was the only quadriceps property that was independently associated with the different measures of PA after controlling for a basic set of known determinants of PA, quadriceps strength or power, or isometric or isokinetic quadriceps endurance. Future longitudinal studies should investigate its potential as a modifiable determinant of PA.
关于慢性阻塞性肺疾病（COPD）患者日常体力活动（PA）的可改变决定因素的知识对于设计有效的 PA 干预措施至关重要。本研究旨在确定股四头肌力量、功率和耐力对 COPD 患者日常 PA 的贡献。此外，对于股四头肌耐力，我们还旨在确定根据运动方式（等张、等长或等速）的不同，这种关联的变化程度。使用多中心横断面试验设计，我们通过双变量和部分 Pearson 相关分析（r）和多元线性回归模型（ΔR）确定股四头肌功能对日常 PA（步数、久坐时间和进行中到非常剧烈体力活动[MVPA]的时间）的贡献。预定义的控制因素包括性别、年龄、体重指数（BMI）、COPD 评估测试、一秒用力呼气量占预计值的百分比（FEV）和 6 分钟步行试验中行走的距离。共纳入 81 例 COPD 患者（平均±标准差：年龄 67±8 岁，FEV 57±19%，每日步数 4968±3319，每日久坐时间 1016±305 分钟，MVPA 时间 83±45 分钟）。发现股四头肌功能与 PA 测量之间存在小到中度的双变量相关性（r=0.225 至 0.452，p<0.05）。最佳多元线性回归模型解释了数据中 38-49%的方差。等张耐力是唯一能改善所有 PA 模型的肌肉贡献者；每日步数（ΔR=0.04[相对改善 13%]，p=0.026）、每日久坐时间（ΔR=0.07[23%]，p=0.005）和 MVPA 分钟（ΔR=0.08[20%]，p=0.001）。即使在控制肌肉力量、功率或等长-等速耐力特性的情况下，等张耐力也与大多数 PA 变量独立相关（r=0.246 至 0.384，p<0.05）。相比之下，当控制等张耐力时，肌肉的力量、功率、等长或等速耐力特性与 PA 测量均无独立相关性（r=0.037 至 0.219，p>0.05）。总之，COPD 患者的股四头肌力量、功率和耐力特性与 PA 低度到中度相关。等张股四头肌耐力是唯一一种在控制一系列已知 PA 决定因素（股四头肌力量或功率、等长或等速股四头肌耐力）后，与不同 PA 测量值独立相关的股四头肌特性。未来的纵向研究应探讨其作为 PA 可改变决定因素的潜力。
