Purpose: To systematically review the existing scientific evidence regarding the effects of physical exercise on the fitness level of people with intellectual disabilities.Methods: Following the checklist of the Preferred Reporting Items for Systematic review and Meta-Analysis Protocols, the PubMed, CINAHL, SPORTDiscus, and Scopus databases were searched using specific keywords up to January 2018. The methodological quality of the studies found was rated by the means of specific scales according to their specific design.Results: A total of 44 studies were selected. The majority of the included studies were randomized controlled trials (n = 17), followed by non-controlled studies (n = 11), non-randomized controlled trials (n = 10), and comparative studies (n = 6). Aerobic, strengthening, and combined exercise programs were the most frequently proposed interventions. Exercise showed to have significant effects on the cardiorespiratory and muscular fitness. Not all the selected studies reported improvements in parameters related to body composition.Conclusions: There is sufficient scientific evidence for the beneficial effects of exercise on the cardiovascular and muscular fitness of adults with mild/moderate ID. There is a need for more studies focused on the impact of physical exercise on the body composition of this population, and those that aim at identifying the impact of alternative interventions.IMPLICATIONS FOR REHABILITATIONThere is a need for basic guidelines that can help rehabilitation professionals to prescribe exercise for maintaining and improving physical fitness in the adults with intellectual disabilities.In adults with intellectual disabilities, aerobic exercise has beneficial effects on cardiovascular and muscular fitness, flexibility, and range of motion.No firm conclusion can be made regarding the effects of aerobic, muscular, and combined training programs on the body composition of adults with intellectual disabilities.Rehabilitation professionals should be aware that scientific evidence regarding the prescription of alternative exercise protocols in adults with intellectual disabilities (i.e. dancing, water-based exercise, animal therapy, etc) is scarce.
Keywords: Exercise; fitness; intellectual disability; review; training.