RT Journal Article
SR Electronic
T1 Are COPD patients with fatigable quadriceps less physically active? Preliminary results
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP OA477
DO 10.1183/13993003.congress-2015.OA477
VO 46
IS suppl 59
A1 Carlos A. Camillo
A1 Christian Osadnik
A1 Chris Burtin
A1 Heleen Demeyer
A1 Miek Hornikx
A1 Wim Janssens
A1 Thierry Troosters
YR 2015
UL http://erj.ersjournals.com/content/46/suppl_59/OA477.abstract
AB Background: Contractile quadriceps fatigue is associated with acute reductions in exercise capacity in COPD (Gagnon, 2009). We hypothesized patients with fatigable quadriceps would present with reduced physical activity (PA).Aim: To compare PA between COPD patients who develop quadriceps fatigue (F) after exercise training and those who are less fatigable (NF).Methods: 19 patients with COPD (65±8years; FEV1 51±17%pred) referred to pulmonary rehabilitation performed PA monitoring (McRoberts; NL) for 7 days before starting exercise training. Potentiated quadriceps twitch force (Twqpot) was measured via magnetic stimulation before and after 1 exercise session in the 2nd training week to determine muscle fatigability. A >15% decrease in Twqpot from initial value defined F. PA levels were compared between F and NF.Results: Test-day training loads were similar for F and NF (64±9% vs 66±10%Wmax for cycling; 77±4% vs 79±7%6MWD speed for walking, p>0.05). F had on average 32% lower daily step count and spent 37% less energy during active time compared to NF, however these differences were not statistically significant (table 1). Conclusion: These preliminary data suggest individuals who develop contractile quadriceps fatigue after an exercise session have lower PA levels. When confirmed in a larger sample, our data suggest quadriceps fatigability could be an (as yet) undiscovered mechanism explaining physical inactivity in COPD.