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Background: Approximately 35% of individuals over age 70 report difficulty with mobility. Muscle weakness has been demonstrated to be one contributor to mobility limitations in older adults. The purpose of this study was to examine the moderating effect of brain-predicted age difference (an index of biological brain age/health derived from structural neuroimaging) on the relationship between leg strength and mobility. Methods: In community dwelling older adults (N = 57, 74.7 ± 6.93 years; 68% women), we assessed the relationship between isokinetic leg extensor strength and a composite measure of mobility [mobility battery assessment (MBA)] using partial Pearson correlations and multifactorial regression modeling. Brain predicted age (BPA) was calculated from T1 MR-images using a validated machine learning Gaussian Process regression model to explore the moderating effect of BPA difference (BPAD; BPA minus chronological age). Results: Leg strength was significantly correlated with BPAD (r = −0.317, p < 0.05) and MBA score (r = 0.541, p < 0.001). Chronological age, sex, leg strength, and BPAD explained 63% of the variance in MBA performance (p < 0.001). BPAD was a significant moderator of the relationship between strength and MBA, accounting for 7.0% of MBA score variance [△ R 2 = 0.044, F (1,51) = 6.83, p = 0.01]. Conditional moderation effects of BPAD indicate strength was a stronger predictor of mobility in those with a great BPAD. Conclusion: The relationship between strength and mobility appears to be influenced by brain aging, with strength serving as a possible compensation for decline in neural integrity. [ABSTRACT FROM AUTHOR]

For well over 20 centuries, the muscle wasting (sarcopenia) and weakness (dynapenia) that occurs with old age has been a predominant concern for mankind. Exercise has long been suggested as a treatment to combat sarcopenia and dynapenia, as it exerts effects on both the nervous and muscular systems that are critical to positive physiological and functional adaptations (e.g., enhanced muscle strength). For more than two decades, scientists have recognized the profound role that progressive resistance exercise training (RET) can have on increasing muscle strength, muscle size, and functional capacity in older adults. In this review article, we discuss how RET can be used in the management and prevention of sarcopenia and dynapenia. We first provide an overview of the evidence for this notion and highlight certain critical factors--namely, exercise intensity, volume, and progression--that are key to optimizing the resistance exercise prescription. We then highlight how many, if not most, of the commonly prescribed exercise programs for seniors are not the "best practices" and subsequently present easy-to-read guidelines for a well-rounded RET program designed for the management and prevention of sarcopenia and dynapenia, including example training programs for the beginner through programs for the advanced senior resistance exerciser. These guidelines have been written for the academician as well as the student and health-care provider across a variety of disciplines, including those in the long-term care industry, such as wellness instructors or activity directors. [ABSTRACT FROM AUTHOR]