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

Abstract

Plasschaert F, Jones K, Forward M. 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 (V̇ o 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 V̇ o 2 but the children with CP trended toward a drop in their speed and an increase in their V̇ o 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 in 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.