Purpose. This cross-sectional study investigates deficits and associations in muscle strength, 6-minute walking distance (6MWD), aerobic capacity (VO2peak), and physical activity (PA) in independent ambulatory children with lumbosacral spina bifida.

Method. Twenty-tree children participated (13 boys, 10 girls). Mean age (SD): 10.4 (±3.1) years. Muscle strength (manual muscle testing and hand-held dynamometry), 6MWD, VO2peak (maximal exercise test on a treadmill), and PA (quantity and energy expenditure [EE]), were measured and compared with aged-matched reference values.

Results. Strength of upper and lower extremity muscles, and VO2peak were significantly lower compared to reference values. Mean Z-scores ranged from -1.2 to -2.9 for muscle strength, and from -1.7 to -4.1 for VO2peak. EE ranged from 73 - 84% of predicted EE. 6MWD was significantly associated with muscle strength of hip abductors and foot dorsal flexors. VO2peak was significantly associated with strength of hip flexors, hip abductors, knee extensors, foot dorsal flexors, and calf muscles.

Conclusions. These children have significantly reduced muscle strength, 6MWD, VO2peak and lower levels of PA, compared to reference values. VO2peak and 6MWD were significantly associated with muscle strength, especially with hip abductor and ankle muscles. Therefore, even in independent ambulating children training on endurance and muscle strength seems indicated.