A predominantly home-based progressive resistance exercise program increases knee extensor strength in the short-term in people with chronic obstructive pulmonary disease: a randomised controlled trial

Questions: Does a 12-week, predominantly home-based program of progressive resistance exercises reduce impairments, activity limitations, and participation restrictions in people with chronic obstructive pulmonary disease? Are any gains maintained 12 weeks after the cessation of the program? Design: Randomised controlled trial with concealed allocation, assessor blinding, and intention-to-treat analysis. Participants: 54 people with moderately severe chronic obstructive pulmonary disease not undergoing pulmonary rehabilitation. Intervention: The experimental group performed six progressive resistance exercises three times per week (once a week hospital-based, twice a week home-based) for 12 weeks. Exercise intensity was three sets of 8 to 12 repetition maximum progressed against elasticised bands of increasing resistance. The control group received no intervention. Outcome measures: Primary outcomes were strength (knee extensor, hip abductor, shoulder horizontal flexor, shoulder flexor) measured using hand-held dynamometry, and walking capacity measured by the 6-minute Walk Test performed before and after intervention and again at 12 weeks after the cessation of intervention. Results: The experimental group increased their knee extensor strength by 4.9 kg (95% CI 1.1 to 8.7) more than the control group by Week 12. However, this gain was not maintained at Week 24. No difference between the groups was found for any of the other primary outcomes. Conclusions: A predominantly home-based progressive resistance exercise program led to modest improvements in knee extensor strength in people with chronic obstructive pulmonary disease. However, 44% of the experimental group were unable to complete the exercise program, highlighting the need to understand factors influencing adherence to exercise in this population.