A133: A Meta-Analysis on the Impact of Resistance Training on Phase Anglein Middle-Age & Older Individuals

Background/Purpose: The phase angle is commonly utilized to evaluate the nutritional and health status of middle-aged and older individuals, with higher values indicating better cell quantity and function. Resistance exercise is an efficient method to delay the aging process and decrease the likelihood of falls and mortality. The aims of this study were to 1.) to comprehensively determine the impact of resistance training (RT) on phase angle (PhA) in middle-aged and older individuals through a meta-analysis, 2.) to explore the effects of RT on PhA in healthy and unhealthy groups, including subgroups of middle-aged and older individuals, and to 3.) identify the optimal RT protocol (dose–response relationship) to enhance PhA in this population. Methods: We conducted a systematic search of five databases using predefined criteria. Quality assessment followed the Cochrane Handbook 5.1, and Revman 5.3 facilitated effect size aggregation, bias assessment, sensitivity analysis, and subgroup analysis. Results: RT improved PhA in middle-aged and older individuals (d = 0.34, 95% CI: 0.27–0.40, P < 0.05). Subgroup analysis indicated PhA benefits in unhealthy (d = 0.25, 95% CI: 0.10–0.41, P < 0.05) and healthy groups (d = 0.35, 95% CI: 0.28–0.43, P < 0.05). Suspension (d = 0.62), free-weights/machine (d = 0.36), equipment training (d = 0.24), and moderate-intensity RT (d = 0.34) improved PhA. PhA improved with RT performed twice (d = 0.20) or three times (d = 0.38) weekly. Significant improvements occurred after 8 weeks (d = 0.37), 12 weeks (d = 0.35), and ≥24 weeks (d = 0.26) of RT. Low/high-intensity RT, elastic bands, and weekly exercises did not significantly improve PhA. Conclusion/Discussion: RT can enhance PhA in both healthy and unhealthy middle-aged and older individuals. Optimal results are achieved with 2–3 times per week, moderate-intensity RT, lasting ≥ 8 weeks. Given the limited number of comparisons for some subgroups, the conclusions deduced from the subgroup results should be taken as preliminary. Future studies should be designed on the exercise program to compensate for the limitations of the existing studies. At the same time, the study population should be expanded, and additional studies should be conducted on diseased populations other than patients with obesity and diabetes. In addition, the difference in the effect of RT combined with other exercises versus RT only on PhA and the mechanism of its effect are unclear, and more experimental studies on the level of RT effect combined with other exercises on PhA are recommended.