Assessing the impact of aerobic fitness on gait

walking distance, or early fatigue during walking. These problems are primarily caused by motor impairments that lead to gait deviations and increased energy demands of walking which reduce activities in daily life. As a consequence, physical inactivity and low fitness are frequent in this population. The combination of an increased energy demand of walking and reduced aerobic fitness brings about high levels of physical strain of walking. Maintaining adequate (aerobic) fitness levels by physical training is therefore important in children with high energy demands of walking as this keeps up their metabolic reserve and reduces fatigue-related walking problems and inactivity. Exercise testing is applied to measure the energy demands of walking and aerobic fitness, guiding whether treatment should focus on reducing energy cost, increasing fitness, or both. Testing is especially indicated when walking problems and physical activityrelated fatigue are reported. To improve aerobic fitness in deconditioned children, training of sufficient frequency, intensity and duration is required, preferably combined with specific functional exercises.