BackgroundMoving from sitting to standing is a common activity of daily living. The five-repetition sit-tostand test (5STS) is a test of lower limb function that measures the fastest time taken to stand five times from a chair with arms folded. The 5STS has been validated in healthy community-dwelling adults, but data in chronic obstructive pulmonary disease (COPD) populations are lacking. Aims To determine the reliability, validity and responsiveness of the 5STS in patients with COPD. Methods Test-retest and interobserver reliability of the 5STS was measured in 50 patients with COPD. To address construct validity we collected data on the 5STS, exercise capacity (incremental shuttle walk (ISW)), lower limb strength (quadriceps maximum voluntary contraction (QMVC)), health status (St George's Respiratory Questionnaire (SGRQ)) and composite mortality indices (Age Dyspnoea Obstruction index (ADO), BODE index (iBODE)). Responsiveness was determined by measuring 5STS before and after outpatient pulmonary rehabilitation (PR) in 239 patients. Minimum clinically important difference (MCID) was estimated using anchor-based methods. Results Test-retest and interobserver intraclass correlation coefficients were 0.97 and 0.99, respectively. 5STS time correlated significantly with ISW, QMVC, SGRQ, 0.35, 0.42 and 0.46, respectively; all p<0.001). Median (25th, 75th centiles) 5STS time decreased with PR (Pre: 14.1 (11.5, 21.3) vs Post: 12.4 (10.2,16.3) s; p<0.001). Using different anchors, a conservative estimate for the MCID was 1.7 s. Conclusions The 5STS is reliable, valid and responsive in patients with COPD with an estimated MCID of 1.7 s. It is a practical functional outcome measure suitable for use in most healthcare settings.

Quadriceps weakness is an important complication of advanced chronic obstructive pulmonary disease (COPD) but few data exist concerning muscle bulk in early disease. We hypothesised that quadriceps bulk, measured by ultrasound rectus femoris cross-sectional area (USRFCSA), would be reduced in mild, as well as advanced, COPD compared with controls, and would correlate with physical activity.161 patients with stable COPD and 40 healthy subjects had a measurement of USRFCSAand wore a multisensor armband to record physical activity.USRFCSAwas reduced in Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I patients compared with healthy subjects (p=0.0002). Stage II–IV patients had reduced USRFCSA(p<0.0001) compared with controls but were not significantly different from those with stage I disease. Physical activity level was reduced in stage I (p=0.002) and stage II–IV disease compared with controls. Using regression analysis, physical activity level was independently associated with USRFCSAin stage I (p=0.01) but not stage II–IV disease, where residual volume to total lung capacity ratio was the only independent predictor of physical activity level.Quadriceps wasting exists in patients with mild, as well as advanced, COPD, and is independently associated with physical inactivity in GOLD stage I disease. The identification of these patients may guide early lifestyle and therapeutic interventions.

In community-dwelling older adults, usual gait speed over 4 m (4MGS) consistently predicts greater risk of adverse health outcomes. The aims of the present study were to assess the reliability of the 4MGS and the relationship with established health outcome measures in chronic obstructive pulmonary disease (COPD).Test-retest and interobserver reliability of the 4MGS were measured in 80 and 58 COPD patients, respectively. In 586 COPD patients, the 4MGS, as well as forced expiratory volume in 1 s (FEV1), the incremental shuttle walk (ISW), Medical Research Council (MRC) dyspnoea scale and St George's Respiratory Questionnaire (SGRQ) were measured. Participants were stratified according to ''slow'' (,0.8 m?s -1 ) or ''normal'' 4MGS (o0.8 m?s -1 ). Intra-class correlation coefficients for test-retest and interobserver reliability were 0.97 and 0.99, respectively. There was a significant positive correlation between 4MGS with ISW (r50.78; p,0.001) and a negative correlation with MRC dyspnoea scale and SGRQ (r5 -0.55 and -0.44; p,0.001 for both). COPD patients with slow 4MGS had significantly reduced ISW and higher MRC dyspnoea scale and SGRQ than those with preserved walking speed, despite similar FEV1 % predicted.The 4MGS is reliable in COPD, correlates with exercise capacity, dyspnoea and health-related quality of life, and has potential as a simple assessment tool in COPD. @ERSpublications The 4-metre gait speed test is reliable and valid as a simple assessment tool in chronic obstructive pulmonary disease