(5) EFFECT OF A PHYSIO-FEEDBACK-BASED EXERCISE PROGRAM ON PHYSICAL FUNCTION AND BODY COMPOSITION AMONG COMMUNITY-DWELLING OLDER ADULTS

Purpose: Previous research has shown improvements in physical function and body composition among older adults via exercise interventions. However, those studies have largely ignored the potential influence of physio-feedback (i.e., knowledge of results) from baseline testing. With a rise in the accessibility of wearable technology such as smartwatches, many older adults approaching exercise adoption do so knowing their current physiological health which may influence the expected changes in physical function and body composition. Methods: We recruited 259 community-dwelling older adults for an 8-week cluster-randomized controlled trial, comparing changes in body composition and physical function between a physio-feedback-based exercise intervention and control using a two-factorial repeated measures ANOVA. Where significant baseline differences occurred, a repeated measures ANCOVA was used to control for baseline differences. After accounting for excluded (n=26) and withdrawn participants (n=31), we analyzed 202 older adults (female=178, age=74.0±6.8 years, BMI=30.5±6.5kg/m²). Body composition was estimated using multi-frequency bioelectrical impedance analysis (InBody 970^®) and physical function was assessed using the Short Physical Performance Battery (SPPB) as well as handgrip strength, with the peak force output for each hand averaged together. Immediately following baseline assessments, participants in the intervention group each received a one-on-one debrief with a research assistant to discuss their results. Results: There was no significant interaction effect for SPPB nor handgrip strength; however, there was a significant main effect for time with SPPB scores (p< 0.001, ηp²=0.069), observed in both the intervention (PRE=8.8±2.2, POST=9.2±2.3) and control groups (PRE=8.6±2.4, POST=9.2±2.4). There was a significant interaction effect for body fat mass, (p=0.02, ηp²=0.028) visceral fat area (p=0.02, ηp²=0.028), body fat percentage (BF%; p=0.01, ηp²=0.038), and fat-free mass (FFM; p=0.03, ηp²=0.021). However, there were significant baseline differences (p=0.004); after controlling for baseline differences, there was no significant interaction effect (p=0.27, ηp²=0.006) but a significant main effect for time (p< 0.001, ηp²=0.097). The intervention group maintained similar body fat mass (PRE=30.5±12.6kg, POST=30.7±12.9kg), visceral fat area (PRE=145.0±60.1cm², POST=147.0±63.2cm²), BF% (PRE=39.5±9.1%, POST=39.4±8.7%), and FFM (PRE=45.2±10.7kg, POST=45.0±9.6kg). However, the control group accumulated fat mass (PRE=32.4±14.3kg, POST=34.2±14.6kg), visceral fat area (PRE=149.0±64.2cm², POST=163.0±69.2cm²), and BF% (PRE=38.2±10.3%, POST=40.4±10.6%) while also experiencing a decrease in FFM (PRE=49.3±9.0kg, POST=47.8±9.1kg). Conclusions: A physio-feedback-based exercise intervention is feasible to implement with community-dwelling older adults and may prevent age-related increases in adiposity over time. Additionally, the observed main effect for time with SPPB scores indicates a potential learning effect that should be investigated further given its common clinical use. Practical Applications: Clinicians and coaches seeking to stave off age-related declines in body composition among their older adult patients may benefit from using a physio-feedback-based exercise intervention. However, modifications to the intervention are likely required to observe significant increases in FFM and physical function, which is recommended for older adults. Acknowledgements: This work was supported by the National Institute on Minority Health and Health Disparities (grant number R01MD018025) and the Office of the Director, Chief Officer for Scientific Workforce Diversity, Office of the National Institutes of Health (grant number 3R01MD018025-02S1). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The National Institutes of Health had no role in the design, analysis, or writing of this article.