Physical activity, metabolic issues, and assessment.

Considering the important health consequences of physical activity and aerobic capacity, current guidelines recommend that all individuals should be physically active all or most days of the week. Relatively little is known about physical activity patterns or aerobic capacity of individuals who have disabilities, but existing data clearly show a disturbing pattern of low levels of physical activity and aerobic capacity in most, if not all, populations who have disabilities. More research is needed on all populations who have disabilities, not only documenting current levels of physical activity and aerobic capacity but also investigating potential strategies for improvement. Unfortunately, the techniques available for measuring physical activity have significant shortcomings. DLW shows considerable promise, but it is expensive and not appropriate for population studies. All other techniques have significant shortcomings in regard to tracking individual physical activity patterns, but they might provide valuable insight regarding group behavior. Although maximal exercise testing is the gold standard for measuring aerobic capacity, this technique is difficult to use in many populations that have disabilities. Few protocols have been validated for use with individuals who have disabilities, and indiscriminant use of protocols developed for nondisabled populations is inappropriate when testing individuals who have disabilities. Submaximal testing could be of considerable utility, but few protocols have been validated. For most populations that have disabilities, submaximal tests designed to predict VO2peak are not valid, given the altered disability-specific physiological responses, which usually result in gross overpredictions. Submaximal tests designed to compare (either intra or inter individual comparisons) physiological responses at predetermined submaximal work rates show considerable promise. Both populations of children who have disabilities that are discussed herein exhibit low levels of physical activity and aerobic capacity, which is consistent with most of the literature for any group that has disabilities. Although the mechanisms for producing lower levels of activity and aerobic capacity differ among children who have mental retardation and children who have CP, the outcome is similar in both populations. Appropriate testing methodology differs between these populations, and the different mechanisms involved demonstrate the disability-specific nature of research in children who have disabilities, which also illustrates the difficulty of producing general guidelines for exercise and physical activity interventions. Current data clearly show the need for improving both physical activity patterns and aerobic capacity in most children who have disabilities. Failure to accomplish this goal will ultimately have considerable negative health outcomes for individuals who have disabilities.