@article {Gagnonp1255, author = {Philippe Gagnon and Val{\'e}rie Coats and Laurent Bouyer and Cynthia Brouillard and Fran{\c c}ois Maltais and Didier Saey}, title = {Lower limb fatigue, during walking in patients with COPD}, volume = {38}, number = {Suppl 55}, elocation-id = {p1255}, year = {2011}, publisher = {European Respiratory Society}, abstract = {Background: The contribution of quadriceps muscle fatigue to cycling exercise intolerance is well recognized in COPD. Whether muscle fatigue occurs in plantar and dorsi-flexor muscles during walking is still unknown in these patients.Aim: To compare muscle strength and fatigue induced by walking exercise in plantar and dorsi-flexor muscles between COPD patients and healthy subjects.Method: Eleven patients with COPD (FEV1 58{\textpm}15\%pred.) and 11 healthy subjects matched for age and BMI performed a 12-minute walking exercise. The speed and slope of the treadmill were adjusted to achieve a targeted 40 Kcal energy expenditure for each subject. Maximal voluntary contraction (MVC) and twitch force (Tw) measured by magnetic stimulation were obtained for plantar and dorsi-flexor muscles prior to and 15 minutes after exercise.Results: At rest, MVC and Tw tended to be lower in COPD patients compared to healthy subjects for plantar (51.5{\textpm}12.8 vs 65.6{\textpm}21.7 kg, p=0.08 and 10.9{\textpm}3.7 vs 13.2{\textpm}2.6 kg, p=0.09) and dorsi-flexor (24.8{\textpm}10.7 vs 32.7{\textpm}8.4 kg, p=0.06 and 4.2{\textpm}1.4 vs 6.12{\textpm}1.3 kg, p\<0.05) muscles. In COPD patients both, MVC and Tw were significantly decreased 15 min after exercise for plantar-flexor (-8{\textpm}10\% and -15{\textpm}21\%, p\<0.05) and for dorsi-flexor (-6{\textpm}11\% and-31{\textpm}19\%, p\<0.05) muscles. There was no difference in healthy subjects post-exercise for either plantar-flexor (1{\textpm}10\% and -4{\textpm}14\%), or dorsi-flexor muscles (1{\textpm}3\% and 4{\textpm}7\%).Conclusion: Muscle weakness and a susceptibility to develop muscle fatigue after walking occur in the plantar and dorsi-flexor muscles in patients with COPD compared to controls.Project supported by the R{\'e}seau en sant{\'e} respiratoire du FRSQ}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/38/Suppl_55/p1255}, eprint = {https://erj.ersjournals.com/content}, journal = {European Respiratory Journal} }