Initiation of movement and energy expenditure in children with developmental delay: a case-control study.

BACKGROUND Lower levels of physical activity in children with developmental delay (DD) usually are attributed to higher energy costs. However, there is no evidence that children with DD spend more energy on daily physical activities, such as walking. OBJECTIVE The aim of this study was to compare energy costs during walking and movement initiation times in children with DD and children with typical development (TD) and matched for age. DESIGN This was a case-control study. METHODS Children who were 3 and 5 years old and had DD (n=12) or TD (n=12) participated in the study. Measurements included ranges of motion in the lower extremities, physiological costs of walking, and movement initiation times. A task designed to evaluate the initiation of movement (the "go play with the toy" task) was used to examine the reaction times for children's goal-directed walking. RESULTS The physiological costs of walking were similar in the 2 groups; however, children with DD walked at a lower speed than children with TD. Importantly, children with DD took more time to initiate goal-directed walking. LIMITATIONS The nature of the study design limited causal inference from the results. CONCLUSIONS Children who were 3 to 5 years old and had DD had delays in goal-directed movement that may not have been attributable to motor impairments. The findings suggest that therapists should evaluate the movement initiation ability of 3- to 5-year-old children with DD as part of the design of an overall intervention plan.