similar “doses” of exercise can have the same health benefits for people with disabilities.

In recent years there has been a modest but growing increase in the number of exercise-related studies that have targeted people with disabilities. Although the majority of these studies are not randomized controlled trials (RCTs) and had limited sample sizes, they are part of a growing effort among researchers to understand the effects of exercise in improving health among people with disabilities.^{1,2,5,6,7,8,9} However, there is a limited amount of data on the effects of exercise in reducing or mitigating specific secondary conditions that are related to a primary disabling condition.^10,15

This paper reviews 10 RCTs that tested an exercise intervention to ameliorate the following secondary conditions: deconditioning, fatigue, and pain. Two primary disabling conditions were targeted: multiple sclerosis and spinal cord injury. A glossary at the end of this paper describes the assessment instruments used in the studies reviewed. To identify relevant studies, we conducted a literature search for the period from 1990 to 2005. The databases searched were PubMed/MEDLINE and Cumulative Index to Nursing and Allied Health Literature (CINAHL). The keywords used to identify peer reviewed articles were “exercise,” “physical activity,” “secondary conditions,” “disability,” “multiple sclerosis,” and “spinal cord injury.” The studies selected had to fulfill the following criteria: (1) the enrolled subjects had to have a spinal cord injury or multiple sclerosis; (2) the intervention targeted deconditioning, fatigue, or pain; (3) the trial involved a prospective randomization methodology; (4) the treatment involved some type of exercise regimen; and (5) the study was published in English. A total of 10 articles satisfied the inclusion criteria.

Deconditioning is associated with low levels of physical fitness (e.g., low levels of aerobic power and muscle strength and endurance, higher fat to lean muscle ratio, and poor flexibility) and often occurs as a result of high levels of sedentary behavior. It leads to a loss of cardiorespiratory endurance and musculoskeletal function, subsequently reducing a person’s ability to perform various physical tasks, including activities of daily living, such as dressing and bathing, and instrumental activities of daily living, such as transfers, rolling up ramps, walking, and wheeling.

Six RCTs examined the effects of exercise on deconditioning in individuals with spinal cord injuries (one study) or multiple sclerosis (five stud-