Reproducibility of Maximal and Submaximal Exercise Testing in "Normal Ambulatory" and "Community Ambulatory" Children and Adolescents With Spina Bifida: Which Is Best for the Evaluation and Application of Exercise Training?

Background. With emerging interest in exercise and lifestyle interventions for children and adolescents with spina bifida, there is a need for appropriate measurements in exercise testing.

Objective. The purpose of this study was to assess both reliability and agreement of maximal and submaximal exercise measures in "normal ambulatory" and "community ambulatory" children and adolescents with spina bifida.

Design. This was a reproducibility study.

Methods. Twenty-three children and adolescents with spina bifida (10 normal ambulatory and 13 community ambulatory) participated in the study. Maximal exercise outcomes were measured using a graded treadmill test. Peak measures (peak oxygen uptake [(V) over dotO(2)peak], peak heart rate [HRpeak], heart rate response [HRR], and oxygen pulse) were recorded. For submaximal measures, heart rate (HR) and oxygen uptake ((V) over dotO(2)) at the ventilatory threshold and oxygen uptake efficiency slope (OUES) were derived from the maximal measures. Functional performance was measured as the 6-minute walking distance and the maximal speed during the treadmill test. After checking for normality and heteroscedasticity, paired t tests, intraclass correlation coefficients (ICCs), and the smallest detectable difference (SDD) or the coefficient of variation (CV) were calculated.

Results. Performance measures showed good reliability and agreement. For maximal measures, acceptable ICCs were found for all measures. For submaximal measures, only HR at the ventilatory threshold showed an ICC of less than .80. Agreement showed a CV of less than 10% for all measures, except for (V) over dotO(2) at the ventilatory threshold, HRR, and OUES.

Limitations. Limitations of the study include missing data due to equipment failure. Furthermore, the outcomes were limited to normal ambulatory and community ambulatory children and adolescents with spina bifida.

Conclusions. Both maximal and submaximal measures of exercise testing can be used for discriminative purposes in ambulatory children and adolescents with spina bifida. For evaluative purposes, HR measures are superior to (V) over dotO(2) measures, while taking into account the individual variation of 5% to 8%. The SDD was 0.5 km/h for peak speed and 36.3 m for 6-minute walking distance. Heart rate response, oxygen pulse, and OUES are not recommended in the evaluation of exercise testing in this population.