The aims of this study were to determine the relation between gait kinematics (center of mass excursions) and measures of oxygen consumption and oxygen cost. Fourteen independent ambulating children with myelomeningocele (nine females, five males; mean age 8 years 7 months) and thirteen children with no history of neuromuscular disorder were evaluated. At their comfortable walking speed all patients exhibited oxygen cost and oxygen consumption values that exceeded the normal level by more than 1 SD. Pelvic obliquity demonstrated the strongest relation with oxygen cost which suggests that ultimately hip abductor strength may play a key role in energy demands during gait. Despite the exaggerated pelvic kinematics, vertical and horizontal center of mass excursions of the trunk and whole-body during the gait cycle were not significantly greater than normal (p>0.05). Decreased self-selected walking velocity at which many of these children consider comfortable and stable may be predicated on an optimal center of mass movement that approximates the magnitude observed in normal gait. The slower walking velocity decreases walking efficiency. Conversely, the increased center of mass movement that would accompany a faster gait would probably impose intolerable oxygen consumption levels. Strengthening programs that focus on the gluteus medius and maximus to decrease compensatory trunk and pelvic motions, allowing the patients to adopt a faster gait without exacerbating kinematic and center of mass motions and which enabled more efficient walking hold promise for these patients.