The Relationship Between Muscle Strength, Physical Activity Level, and Functional Independence in Older Adults: A Narrative Review

Population aging is associated with progressive declines in muscle strength, physical performance, and overall functional capacity. Maintaining functional independence is a primary goal of healthy aging because it directly influences quality of life, healthcare utilization, and social participation. Growing evidence indicates that muscle strength and physical activity are among the strongest determinants of independent functioning in later life. To review current evidence regarding the relationship between muscle strength, physical activity level, and functional independence among older adults and to discuss the underlying physiological mechanisms and clinical implications. A narrative review was conducted using literature retrieved from PubMed, Scopus, Web of Science, Google Scholar, and international public health databases. Priority was given to systematic reviews, meta-analyses, randomized controlled trials, and cohort studies published between 2020 and 2025. Thematic synthesis was performed to evaluate the influence of muscle strength and physical activity on functional independence. Current evidence consistently demonstrates that muscle strength is a major predictor of functional independence in older adults. Higher levels of physical activity are associated with improved muscle function, mobility, balance, and performance of activities of daily living. Resistance training appears particularly effective in preserving functional capacity by enhancing muscular strength and reducing the risk of disability. Handgrip strength and lower-extremity strength are strongly associated with mobility, fall prevention, and independent living. Muscle strength and physical activity represent fundamental determinants of functional independence in older adults. Strategies aimed at increasing participation in physical activity, particularly resistance training, may contribute significantly to healthy aging and prevention of disability.