Department of Respiratory Medicine, University of Toronto, Toronto, ON, Canada; Respiratory Diagnostic and Evaluation Services, West Park Healthcare Centre, Toronto, ON, Canada.
Department of Respiratory Medicine, University of Toronto, Toronto, ON, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada.
Chest. 2012 Feb;141(2):413-419. doi: 10.1378/chest.11-1059. Epub 2011 Jul 21.
Walking is frequently used in the exercise rehabilitation of patients with COPD. Walking ability can be characterized by the two-parameter hyperbolic relationship between endurance and speed. One parameter, critical walk speed (s_critical), represents the maximum speed that can be endured indefinitely. The purpose of this study was to: (1) determine the effect of pulmonary rehabilitation on the critical speed and (2) compare the critical speed with the speed chosen during self-paced walking.
We estimated critical speed in patients with COPD before and after rehabilitation. Patients completed four high-intensity constant-speed walk tests to intolerance on a 30-m course. The parameters of the hyperbolic relationship were determined using nonlinear regression of endurance on speed. Participants also completed self-paced walks: (1) for as long as they could, (2) at their "usual" and "fast" speeds, and (3) as a 6-min walk test.
Twelve participants (FEV(1) [SD], 41 [16] % predicted; FEV(1)/FVC, 41 [12]) completed the study. At baseline, the critical speed (65 [12] m/min) was not significantly different from the self-paced, usual, or 6-min walk speeds (65 [12], 67 [14], and 63 [15] m/min, respectively). There was a significant increase in critical speed (6 [1-10] m/min) and 6-min speed (16 [10-21] m/min) after rehabilitation, without changes in the self-paced, usual, or fast speeds.
Patients with COPD increase their critical walk speed after pulmonary rehabilitation. The pace chosen during common walk tasks is closely related to critical speed; this relationship is altered after rehabilitation.
ClinicalTrials.gov; No.: NCT00781183; URL: www.clinicaltrials.gov.
步行常被用于 COPD 患者的运动康复。步行能力可通过耐力与速度之间的双参数双曲线关系来描述。其中一个参数，临界步行速度（s_critical），代表能够无限持续的最大速度。本研究的目的是：（1）确定肺康复对临界速度的影响，（2）比较临界速度与自我选择步行速度。
我们在康复前后估计了 COPD 患者的临界速度。患者在 30 米的赛道上完成了四项高强度定速步行试验直至无法耐受。使用耐力与速度的非线性回归确定双曲线关系的参数。参与者还完成了自我选择的步行测试：（1）尽他们所能，（2）以他们的“常规”和“快速”速度，以及（3）作为 6 分钟步行测试。
12 名参与者（FEV(1) [SD]，41 [16] %预测值；FEV(1)/FVC，41 [12]）完成了研究。在基线时，临界速度（65 [12] m/min）与自我选择的常规、快速或 6 分钟步行速度（65 [12]、67 [14]和 63 [15] m/min）均无显著差异。康复后，临界速度（6 [1-10] m/min）和 6 分钟步行速度（16 [10-21] m/min）显著增加，而自我选择的常规、快速或快速步行速度没有变化。
COPD 患者在肺康复后增加了他们的临界步行速度。在常见步行任务中选择的步伐与临界速度密切相关；这种关系在康复后发生了变化。
ClinicalTrials.gov；编号：NCT00781183；网址：www.clinicaltrials.gov。
