RT Journal Article
SR Electronic
T1 Upper and lower limb muscles in patients with COPD: similarities in muscle efficiency but differences in fatigue resistance
JF Respiratory Care
FD American Association for Respiratory Care
SP respcare.02439
DO 10.4187/respcare.02439
A1 Eduardo Foschini Miranda
A1 Carla Malaguti
A1 Paulo Henrique Marchetti
A1 Simone Dal Corso
YR 2013
UL http://rc.rcjournal.com/content/early/2013/06/25/respcare.02439.abstract
AB Background: Peripheral muscle dysfunction is a common finding in patients with chronic obstructive pulmonary disease (COPD); however, the structural adaptation and functional impairment of the upper and lower limb muscles do not seem to be homogenous. Objective: To compare muscle fatigue and recovery time between two representative muscles of the upper limb (middle deltoid, MD) and lower limb (quadriceps femoris, QF). Methods: Twenty-one patients with COPD (with forced expiratory volume in 1 s of 46.1 ± 10.3% predicted) underwent maximal voluntary isometric contraction (MVIC) and an endurance test (ET, 60% MIVC) to the limit of tolerance. The MVIC was repeated after 10 minutes, 30 minutes, 60 minutes and 24 hours for both the QF and MD. Surface electromyography was recorded throughout the ET. Results: A significant fall in MVIC was observed only for the MD between ten and sixty minutes after the ET. A significant increase of the root mean square and a greater decline in median frequency throughout the ET occurred for the MD compared with the QF. When dyspnea and fatigue scores were corrected by endurance time, higher values were observed for MD (0.07 and 0.08, respectively) in relation to QF (0.02 and 0.03, respectively). Conclusion: Patients with COPD presented a higher fatigability of a representative upper limb muscle (MD) compared with a lower limb muscle (QF).