Background: Frailty is a geriatric syndrome, which is highly prevalent in community-dwelling older adults and is associated with a variety of unwanted health outcomes, including dependency and institutionalization. Physical activity (PA) interventions may be of great importance in frail people to improve the frailty status, muscle strength, physical performance and muscle mass.
Methods: A narrative review of randomized-controlled trails was performed, including frail and prefrail community-dwelling older adults. Included were studies with different PA interventions, such as aerobic activity, strength and balance training, stretching, and a combination of these methods.
Results: Overall, 14 studies were included. The PA interventions led to a significant reduction in the frailty status (3/5 studies), to an increase in muscle strength (4/8 studies), to improved physical performance (7/11 studies), and to an increase in muscle mass (1/4 studies), when compared to the control group. The studies analyzed differed in various aspects of study protocols (training protocol, intensity, frequency, follow-up time, measuring tools) and delivery method of intervention (health professionals, lay volunteers, at home in health care institutions).
Conclusions: Although it was not consistently reported in the studies that PA interventions are successful in increasing muscle mass in frail and prefrail older people, the results support the effectiveness of PA interventions on the reduction of frailty, and the increase in muscle strength and physical performance.
Keywords: Exercise training; Frailty; Intervention studies; Older adults.