Body composition is the fourth component of health-related fitness. A person with a high level of cardiovascular fitness will usually have a low level of body fat.³⁹ The longer a child or adolescent remains obese, the greater the likelihood that they will become obese adults.³⁶ Therefore, it is extremely important for physical therapists to identify children with disabilities who have weight problems, and develop activities that will assist the child in becoming more active.

In general, children with disabilities are more likely to become obese because of their higher rate of inactivity.^14,37 Winnick and Short found higher skinfold values in children with visual impairments, spinal neuromuscular conditions, and congenital anomalies or amputations compared to nondisabled controls.⁸ Rimmer reported high levels of obesity among children with intellectual disability, especially children with Down syndrome.³⁷ This was confirmed in another study by Takeuchi, who found that in Japanese children with intellectual disability, obesity levels were higher than in children without intellectual disability.⁴⁰ Agre and coworkers reported that the higher the level of the lesion in children with spina bifida, the higher amount of body fat and the less active they were.²³ Mita and coworkers also found very high levels of obesity in children with spina bifida (58%), and recommended that nutritional and exercise programs be started early to prevent the development of this disorder.¹⁴

The most effective way to improve body composition is by increasing physical activity levels through a variety of activities. The more active a child is, the greater the likelihood that he or she will burn off excess calories as opposed to storing them as body fat. Participating in cardiovascular activities and increasing muscular strength and endurance will help control a child's weight gain during childhood and adolescence.