The Effect of Simulating Weight Gain on the Energy Cost of Walking in Unimpaired Children and Children With Cerebral Palsy

Objective: To examine the effect of simulating weight gain on the energy cost of walking in children with cerebral palsy (CP) compared with unimpaired children. Design: Repeated measures, matched subjects, controlled. Setting: University hospital clinical gait and movement analysis laboratory. Participants: Children (n=42) with CP and unimpaired children (n=42). Interventions: Addition of 10% of body mass in weight belt. Main Outcome Measures: Energy cost of walking parameters consisting of walking speed, Physiological Cost Index, Total Heart Beat Index, oxygen uptake ((V) over doto(2)), gross oxygen cost, nondimensional net oxygen cost, and net oxygen cost with speed normalized to height were measured by using a breath-by-breath gas analysis system (K4b(2)) and a light beam timing Gate system arranged around a figure 8 track. Two walking trials were performed in random order, with and the other without wearing a weighted belt. Results: Children with CP and their unimpaired counterparts responded in fundamentally different ways to weight gain. The unimpaired population maintained speed and (V) over doto(2) but the children with CP trended toward a drop in their speed and an increase in their (V) over doto(2) The oxygen consumption of children with CP showed a greater dependence on mass than the unimpaired group (P=.043). Conclusions: An increase of a relatively small percentage ill body mass began to significantly impact the energy cost of walking in children with CP. This result highlights the need for weight control to sustain the level of functional walking in these children.