Treadmill Testing of Children Who Have Spina Bifida and Are Ambulatory: Does Peak Oxygen Uptake Reflect Maximum Oxygen Uptake?

BackgroundEarlier studies have demonstrated low peak oxygen uptake (V̇o2peak) in children with spina bifida. Low peak heart rate and low peak respiratory exchange ratio in these studies raised questions regarding the true maximal character of V̇o2peak values obtained with treadmill testing.ObjectiveThe aim of this study was to determine whether the V̇o2peak measured during an incremental treadmill test is a true reflection of the maximum oxygen uptake (V̇o2max) in children who have spina bifida and are ambulatory.DesignA cross-sectional design was used for this study.MethodsTwenty children who had spina bifida and were ambulatory participated. The V̇o2peak was measured during a graded treadmill exercise test. The validity of V̇o2peak measurements was evaluated by use of previously described guidelines for maximum exercise testing in children who are healthy, as well as differences between V̇o2peak and V̇o2 during a supramaximal protocol (V̇o2supramaximal).ResultsThe average values for V̇o2peak and normalized V̇o2peak were, respectively, 1.23 L/min (SD=0.6) and 34.1 mL/kg/min (SD=8.3). Fifteen children met at least 2 of the 3 previously described criteria; one child failed to meet any criteria. Although there were no significant differences between V̇o2peak and V̇o2supramaximal, 5 children did show improvement during supramaximal testing.LimitationsThese results apply to children who have spina bifida and are at least community ambulatory.ConclusionsThe V̇o2peak measured during an incremental treadmill test seems to reflect the true V̇o2max in children who have spina bifida and are ambulatory, validating the use of a treadmill test for these children. When confirmation of maximal effort is needed, the addition of supramaximal testing of children with disability is an easy and well-tolerated method.