Treadmill testing of children who have spina bifida and are ambulatory: does peak oxygen uptake reflect maximum oxygen uptake?

BACKGROUND

Earlier studies have demonstrated low peak oxygen uptake ((.)Vo(2)peak) 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 (.)Vo(2)peak values obtained with treadmill testing.

OBJECTIVE

The aim of this study was to determine whether the Vo(2)peak measured during an incremental treadmill test is a true reflection of the maximum oxygen uptake ((.)Vo(2)max) in children who have spina bifida and are ambulatory.

DESIGN

A cross-sectional design was used for this study.

METHODS

Twenty children who had spina bifida and were ambulatory participated. The (.)Vo(2)peak was measured during a graded treadmill exercise test. The validity of (.)Vo(2)peak measurements was evaluated by use of previously described guidelines for maximum exercise testing in children who are healthy, as well as differences between Vo(2)peak and (.)Vo(2) during a supramaximal protocol ((.)Vo(2)supramaximal).

RESULTS

The average values for (.)Vo(2)peak and normalized (.)Vo(2)peak 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 (.)Vo(2)peak and Vo(2)supramaximal, 5 children did show improvement during supramaximal testing.

LIMITATIONS

These results apply to children who have spina bifida and are at least community ambulatory.

CONCLUSIONS

The (.)Vo(2)peak measured during an incremental treadmill test seems to reflect the true (.)Vo(2)max 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.