Comparison of direct and indirect measures of walking energy expenditure in children with hemiplegic cerebral palsy

Abstract

The purpose of this study was to investigate the use of the heart‐rate (HR) version of the energy expenditure index (EEI HR ) as a proxy for measurement of walking oxygen consumption (VO 2 ) in children with cerebral palsy (CP). Thirteen children (eight males, five females; mean age 11 years 2 months [SD 3 years], age range 6 to 15 years) with hemiplegic CP, participated in this study. The study was conducted over three sessions. During session 1, participants were familiarized with testing procedures and given 5 minutes of treadmill walking practice. In session 2, participants completed three 5‐minute walking bouts on the treadmill at 0.67m˙s ‐1 to familiarize themselves with treadmill locomotion. During the final session participants walked at 0.67, 0.89, and 1.12m˙s ‐1 for 5 minutes while gross oxygen consumption (gross VO 2 ; walking VO 2 /speed), net VO 2 ([walking VO 2 ‐resting VO 2 ]/speed), and EEI HR ([walking HR‐resting HR]/speed) were measured during the last 2 minutes of each bout. Correlational analyses indicated no relationship ( p >0.05) between measures of gross VO 2 and EEI HR at each speed. Although no association was evident between net VO 2 and EEI HR at 0.67 and 0.89m˙s ‐1 , a moderate relationship ( r =0.64; p < 0.05) was present between these variables at 1.12m˙s ‐1 . Examination of individual data revealed that most participants displayed an unmatched pattern of response between net VO 2 and EEI HR . Our results suggest that caution should be applied when using EEI HR to estimate walking energy expenditure in children with CP.