Participant characteristics.

Participant characteristics.</p

Late-life disability instrument frequency domain scores for the study group and control group.

The box represents the 25th to 75th percentiles with the horizontal line inside the box representing the median score. The horizontal lines above and below the box represent the maximum (75th percentile plus 1.5*IQR) and minimum (25th percentile minus 1.5*IQR) scores. IQR = interquartile range.</p

Is quadriceps endurance reduced in COPD?: A systematic review

BACKGROUND: Although the aerobic profile of the quadriceps muscle is reduced in COPD, there is conflicting evidence regarding whether this leads to reduced quadriceps muscle endurance. We, therefore, performed a systematic review of studies comparing quadriceps endurance in individuals with COPD with that in healthy control subjects. METHODS: Relevant studies were identified by searching six electronic databases (1946-2011). Full-text articles were obtained after two researchers independently reviewed the abstracts. The results were combined in a random effects meta-analysis, and metaregression models were fitted to assess the influence of the type of measurement. RESULTS: Data were extracted from 21 studies involving 728 individuals with COPD and 440 healthy control subjects. Quadriceps endurance was reduced in those with COPD compared with healthy control subjects (standardized mean difference, 1.16 [95% CI, 1.02-1.30]; P < .001) with a 44.5 s (4.5-84.5 s; P = .029) reduction in COPD (large effect size) when measured using a nonvolitional technique. The relationship between quadriceps endurance in those with COPD and control subjects did not differ when comparing nonvolitional and volitional techniques (P = .22) or when high- or low-intensity tasks (P = .44) were undertaken. CONCLUSIONS: Quadriceps endurance is reduced in individuals with COPD compared with healthy control subjects, independent of the type of task performed

Mean mobility scores by ALE and BLE mobility trajectory from baseline through year 2 (N = 391).

<p>ALE = Advanced Lower-Extremity Function; BLE = Basic Lower-Extremity Function.</p

Baseline health and function by ALE mobility trajectory over 2 year follow-up (N = 391).

<p>Baseline health and function by ALE mobility trajectory over 2 year follow-up (N = 391).</p

Baseline characteristics by ALE mobility trajectory over 2 year follow-up (N = 391).

<p>Baseline characteristics by ALE mobility trajectory over 2 year follow-up (N = 391).</p

Baseline characteristics by BLE mobility trajectory over 2 year follow-up (N = 391).

<p>Baseline characteristics by BLE mobility trajectory over 2 year follow-up (N = 391).</p

Baseline prevalence of self-reported chronic diseases by BLE mobility trajectory (N = 391).

<p>*p<0.01, †p<0.001 for comparisons with Persistently High. ‡p<0.01, §p<0.001 for comparisons with Persistently Poor. BLE = Basic Lower-Extremity Function; OA = Osteoarthritis; PAD = Peripheral Artery Disease.</p