Advancing Age Is Not Associated With Greater Exercise-Induced Muscle Damage: A Systematic Review, Meta-Analysis, and Meta-Regression.

Objective: The aim of this paper was to undertake a Preferred Reporting Items for Systematic Reviews and Meta-Analysis-accordant meta-analysis comparing exercise-induced muscle damage (EIMD) in older and younger adults.

Methods: Google Scholar, PubMed, and SPORTDiscus were searched in June 2023 for the terms "ageing" OR "age" OR "middle-aged" OR "old" OR "older" OR "elderly" OR "masters" OR "veteran" AND "muscle damage" OR "exercise-induced muscle damage" OR "exercise-induced muscle injury" OR "contraction-induced injury" OR "muscle soreness" OR "delayed onset muscle soreness" OR "creatine kinase." From 1,092 originally identified titles, 36 studies were included which had an exercise component comparing a younger against an older group. The outcome variables of EIMD were muscle function, muscle soreness, and creatine kinase. A meta-analysis was conducted on change to EIMD after exercise in older versus younger adults using standardized mean difference (SMD) and an inverse-variance random effects model.

Results: Change after 24 and 72 hr, and peak change, in muscle function was not different between old and young (SMD range = -0.16 to -0.35). Muscle soreness was greater in younger than older adults for all comparisons (SMD range = -0.34 to -0.62). Creatine kinase was greater in younger than older adults at 24 hr (SMD = -0.32), as was peak change (SMD = -0.32). A relationship between sex and peak muscle function change was evident for males (SMD = -0.45), but not females (SMD = -0.44). All other meta-regression was nonsignificant.

Conclusion: Advancing age is not associated with greater symptoms of EIMD. The implication of this study is that the older adults can pursue regular physical activity without concern for experiencing greater EIMD.