The effects of upper limb exercise training on upper limb muscle strength in people with chronic obstructive pulmonary disease: a systematic review and meta-analysis of randomized controlled trials

Background: Upper limb (UL) muscle dysfunction is a common extrapulmonary manifestation of chronic obstructive pulmonary disease (COPD). UL muscle dysfunction is associated with muscle weakness, dyspnea, and exercise intolerance. Although upper limb exercise training (ULET) is typically incorporated in pulmonary rehabilitation programs, its effects on UL muscle strength remains unclear. Objectives: The purpose of this systematic review was to investigate the effectiveness of ULET, in UL muscle strength of people with COPD. Design: This is systematic review and meta-analysis study. Data Sources and Methods: Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) Protocols 2020 guidelines were used for this study. PubMed, Cochrane, CINAHL Plus and SPORTDiscus and clinicaltrials.gov registry were searched from inception to July 2022. Included studies were randomized controlled trials, assessing the effectiveness in muscle strength of ULET, compared with other types of upper or lower limb exercise or no exercise. The quality and risk of bias were assessed using the Physiotherapy Evidence Database (PEDro) scale and certainty of evidence with the Grading of Recommendations, Assessment, Development, and Evaluations approach. Treatment effects of ULET were calculated using standardized mean differences and 95% confidence intervals. Results: Twenty-four studies, with a total sample of 882 patients, were included. Most studies were of moderate quality and high risk of bias. Very low to low certainty evidence indicates a significant difference in UL muscle strength in favor of resistance ULET, compared with lower limb exercise alone or no exercise. No significant differences were found in different types of ULET comparisons. Conclusion: The results of this review showed that resistance ULET could improve UL muscle strength in people with COPD. Most studies, however, were of moderate quality and high risk of bias. Further studies with larger sample sizes, better methodological quality, and standardized training protocols are needed to confirm these findings.