This fact sheet uses a question-and-answer format to summarize issues related to physical fitness in people with mental retardation. Questions and answers address the following topics: a definition of "physical fitness"; the components of physical fitness (muscle strength and endurance, flexibility, body composition, and cardiovascular endurance); how fitness levels of people with mental retardation compare to the general population (substantially lower); how muscle strength and endurance, cardiovascular endurance, and body composition (body fat) in people with mental retardation compare to that of the general population; evidence that people with mental retardation can improve their fitness level; barriers to fitness for individuals with mental retardation (motivation and opportunity); and examples of simple fitness routines. (DB)