Feasibility and effectiveness of eccentric training on limb muscle function and functional performance in patients with COPD: a pilot study

Abstract

<b>Background:</b> Dysfunction of limb muscles is a systemic manifestation of chronic obstructive pulmonary disease (COPD) that requires specific exercise training interventions. <b>Objectives:</b> To assess the feasibility and effectiveness of a low-load eccentric training (LLET) program on limb muscle function and functional performance in individuals with COPD. <b>Methods:</b> Randomized controlled pilot trial. Inpatients with COPD attended 20 sessions of pulmonary rehabilitation. Participants were randomized into LLET group performing treadmill downhill walking and eccentric leg-press on alternate days; controls carried out conventional training. Primary outcome (quadriceps peak torque (QPT)) and secondary outcomes of functional performance (6-min walk distance, 5 sit-to-stand (5STS) time and power, and 10-m gait speed (10mGS)), muscle function (quadriceps quality, maximal and relative 5STS activation, and handgrip strength), BODE index, and Barthel index dyspnea (BID) were assessed before and after the study. <b>Results:</b> Twelve patients (4 women; age 70±7 years; FEV1 50±17% of predicted) completed the study, without adverse events. No changes were found in QPT. The LLET group improved in 5STS time (p=0.045) and BODE index (p=0.015). Both groups improved in BID (p&lt;0.001), 5STS power (p=0.008), and 5STS relative activation (p=0.005). No significant difference was found between groups. <b>Conclusions:</b> Preliminary results suggest that LLET is safe, feasible, and may have beneficial effects on functional performance in COPD patients. However, further studies are necessary to confirm these results and establish short- and long-term effects of LLET on muscle function.