Author(s): CHEN, S., KOSTOV, T., WANG, X., CHEN, J., SUN, J., DIEL, P., Institution: GERMAN SPORT UNIVERSITY COLOGNE, Country: GERMANY, Abstract-ID: 1114

INTRODUCTION:
Skeletal muscle function of postmenopausal women can be categorized into distinct subdomains. For example, Daily life physical function (DLPF) reflects functional independence and the ability to perform daily activities; Maximal strength (MS) represents the force reserve to meet peak mechanical demands such as lifting and protective reactions. Strength endurance (SE) indicates the ability to maintain force output such as holding, stair climbing and repeated lifting. However, among postmenopausal women, it remains unclear which exercise modality optimally improves DLPF, MS or SE, and how the exercise-induced benefits are modulated by intervention characteristics (e.g., weekly training volume and intervention duration), participant characteristics (e.g., age, years since menopause, and baseline body mass), and study-level factors (e.g., funding sources) in specific subdomains. Therefore, in this study, a systematic Review and Network Meta-analysis was conducted to address this gap of knowledge.
METHODS:
Eligible studies were identified in PubMed, Web of Science, SPORTDiscus, and the Cochrane Library. Randomized controlled trials investigating exercise interventions in postmenopausal women were included if they reported outcomes of skeletal muscle function. Different outcome assessment tools within each subdomain were harmonized using an internal reference standard. Bayesian network meta-analysis estimated pooled effect sizes and evaluated prespecified moderators. A tensor-product smoother captured nonlinear interaction between weekly training volume and intervention duration. Risk of bias was assessed by Cochrane RoB2 tool, and evidence certainty was evaluated by CINeMA.
RESULTS:
A total of 180 studies (434 arms; 9546 participants) were included. It turned out that DLPF improvement seems to be maximized by multimodal exercise. The improvement of MS and SE seems to be optimized by specific resistance training. Besides age and years since menopause, exercise benefits are also modulated by baseline body mass and funding source disclosure. Weekly exercise volume is positively associated with MS gain when intervention duration is short; similarly, longer duration appears more beneficial when weekly volume is lower. The simultaneous increases of them, however, attenuate the MS gain. No such antagonistic interaction was observed in the other two subdomains; instead, higher weekly volume associates with greater improvements, whereas longer duration leads to attenuated effects.
CONCLUSION:
Exercise effectively improves muscular function in postmenopausal women; however, different training designs have distinct effects on the defined subdomains of skeletal muscle function. The relationship between weekly exercise volume and intervention duration clearly differed across subdomains. Our findings also indicate that, in addition to the known moderating roles of age and years since menopause, exercise outcomes can be also shaped by baseline participant characteristics and study-level variables.