Objective: To characterize physical activity levels of adults with mental retardation and identify limitations in published research.
Data sources: Key word searches for "mental retardation," "intellectual disability," "learning disability," or "developmental disability" combined with "physical activity" or "habitual exercise" identified articles from MEDLINE, Academic Search Elite, Psych Articles, Health Source, and SPORT Discus. This produced a total of 801 citations.
Study inclusion and exclusion criteria: Published English-language literature that quantitatively measured physical activity levels of adults with mental retardation was included in this review. Fourteen articles met this criterion.
Data extraction: Characteristics of participants, study design, outcome measures, methods of analyses, and findings in terms of percentages, step counts, and accelerometer output were extracted.
Data synthesis: Data were synthesized to identify the percentage of adults with mental retardation who met published health-related physical activity criteria and compare them with adults without mental retardation and to examine study limitations.
Results: The studies with the greatest rigor indicate that one-third of adults or fewer with mental retardation were sufficiently active to achieve health benefits. However, data are insufficient to determine whether adults with mental retardation are less active than the general community.
Conclusions: Future research would be enhanced by including appropriately powered representative samples, by including comparison groups, by validating physical activity questionnaires, and by determining the accuracy of proxy respondents.