Non-linear periodized resistance training in COPD: an international multicentre RCT

<bold>Introduction:</bold> Resistance training (RT) is a key component of pulmonary rehabilitation for people with COPD; however, whether the effects of RT could be optimized by utilizing the exercise principle of non-linear periodization is yet to be determined. <bold>Method:</bold> An international multicenter RCT was conducted across three countries. Fifty-seven people with COPD (70+7 yrs, FEV1% 49+21, 58% male) were randomized to 8 weeks of RT designed per current COPD guidelines to improve muscle strength or to non-linear periodized resistance training (NLPRT) designed to improve muscle strength [4 weeks] but also muscle endurance [4 weeks]. Outcomes included muscle strength, muscle endurance, functional exercise capacity (1-minute sit-to-stand [1-STS], endurance shuttle walk test [ESWT], Unsupported Upper Limb Exercise test [UULEX]), and disease-specific quality of life (QoL). Intention-to-treat (ITT) analysis was utilized, and Cohen's D Effect Sizes [ES] were calculated. <bold>Result:</bold> ITT analysis demonstrated that NLPRT resulted in more pronounced effects on muscle strength (+33% vs. +21%, ES 0.928), muscle endurance (+147% vs. +50%, ES 1.080), ESWT (+168m vs. +36m, ES 0.592), 1-STS (+4 STS vs. 1 STS, ES 0.864), UULEX (+142sec vs. + 42sec, ES=0.819) (all p<0.05) when compared to RT. Both NLPRT and RT resulted in clinically relevant improvements in QoL without differences between modalities. <bold>Conclusion:</bold> These results indicate that 8 weeks of NLPRT yields significantly better outcomes in various dimensions of muscle function and functional capacity when compared to 8 weeks of traditional RT. Consequently, this suggests a potential need for reevaluating and updating current RT guidelines to incorporate these findings.