Table 2– Quadriceps and physical activity measurements in chronic obstructive pulmonary disease (COPD) and control subjects
ControlsCOPDp-value
GOLD IGOLD IIGOLD IIIGOLD IV
USRFCSA mm2640±136530±116511±135504±122509±122<0.0001
QMVC kg34.3±8.829.6±7.227.9±7.327.3±8.825.3±6.8<0.0001
Step count11735±43997960±34306606±33284010±23162219±1157<0.0001
PAL1.69±0.251.56±0.161.47±0.161.4±0.121.38±0.19<0.0001
Armband wearing time h·day−123.57±0.2823.60±0.2623.64±0.3723.57±0.5223.61±0.390.95
Z200/Z50.789±0.030.791±0.030.806±0.030.816±0.030.814±0.030.0002
  • Data are presented as mean±sd, unless otherwise stated. GOLD: Global Initiative for Chronic Obstructive Lung Disease; USRFCSA: ultrasound rectus femoris cross-sectional area; QMVC: quadriceps maximal voluntary contraction; PAL: physical activity level; Z200: impedance at 200 kHz; Z5: impedance at 5 kHz.