PURPOSE: To review and update the evidence of the relationship between physical activity, risk of fall-related injury, and physical function in community-dwelling older people that was presented in the 2018 Physical Activity Guidelines Advisory Committee Scientific Report (PAGAC Report). METHODS: Duplicate independent screenings of 1415 systematic reviews and meta-analyses published between 2006 and 2016 identified from PubMed®, Cochrane Library, and CINAHL databases yielded 111 articles used for the PAGAC Report. The PAGAC Aging Subcommittee members graded scientific evidence strength based upon a five-criteria rubric and assigned one of four grades: strong, moderate, limited, or not assignable. An updated search of 368 articles published between January 2017 and March 2018 yielded 35 additional pertinent articles. RESULTS: Strong evidence demonstrated that physical activity reduced the risk of fall-related injuries by 32% to 40%, including severe falls requiring medical care or hospitalization. Strong evidence also supported that physical activity improved physical function and reduced the risk of age-related loss of physical function in an inverse graded manner among the general aging population, and improved physical function in older people with frailty and with Parkinson's disease. Aerobic, muscle-strengthening, and/or multicomponent physical activity programs elicited the largest improvements in physical function in these same populations. Moderate evidence indicated that for older adults who sustained a hip fracture or stroke, extended exercise programs and mobility-oriented physical activity improved physical function. CONCLUSIONS: Regular physical activity effectively helps older adults improve or delay the loss of physical function and mobility while reducing the risk of fall-related injuries. These important public health benefits underscore the importance of physical activity among older adults, especially those living with declining physical function and chronic health conditions.