Strength and endurance of the dominant quadriceps
| Healthy elderly controls | COPD patients | |
| QMVC kg | 49±13 | 22±10** |
| QMVC % pred | 110±29 | 63±27** |
| QTlim min | 30±0 | 6.9±5.3** |
| QTlim-final fEMG % initial | 99±12 | 87±13** |
| QTlim-V'O2max mL·kg−1·min−1 | 9.6±3.6 | 8.5±2.2 |
| QTlim‐ΔV'O2 rest versus end | 242±197 | 164±123 |
| QTlim‐HRmax beat·min−1 | 118±22 | 96±16** |
| QTlim‐HRmax % pred | 59±11 | 63±14 |
| QTlim‐ΔHR rest versus end | 43±26 | 22±23 |
| QTlim‐V'Emax L·min−1 | 34±17 | 31±12 |
| QTlim‐V'Emax % pred | 18±9 | 55±6** |
| QTlim‐dyspnoea end VAS | 1±1 | 5±3** |
| QTlim‐thigh discomfort VAS | 6±2 | 10±0** |
| Thigh length cm | 39.9±1.0 | 40.9±2.8 |
| Thigh perimeter cm | 49.1±4.1 | 44.6±6.4 |
Data are presented as mean±sd
Both heart rate (HR) and minute ventilation (V'E) values appear referenced to values from Jones et al. 33 for incremental cycle ergometry
COPD: chronic obstructive pulmonary disease
QMVC: quadriceps maximal strength during maximum voluntary contraction
QTlim: quadriceps endurance using a normalised exercise with a load equivalent to 10% of the QMVC and a contraction frequency of 12 min−1
fEMG: median frequency of the electromyographic spectra
V'O2: CO2 production
HRmax: maximum HR
V'Emax: maximum minute ventilation
VAS: visual analogic scale
**: p<0.01