Abstract
The muscle strength of the quadriceps femoris muscle plays an important role in walking in children with spina bifida who have paralyses in lower limb. This study was designed to assess their quadriceps strength and to explore a prediction method of ambulatory status with such factors as muscle strength, neurologic level of lesion and motor development in early childhood. The maximum voluntary strength in isometric knee extension was measured from 61 patients and 92 normal children by strain gauge attached at a distal portion of leg. The patients were classified into five groups according to their current ambulatory status: 1) CA1 whose members were able to walk outdoors without cane, 2) CA2 with cane, 3) HA consisted of patients who walk only indoors with cane, 4) NFA walking for whose patients was a therapy session, and 5) NF whose patients were wheel-chair bound. An index, Z-score associated with the maximum strength and independent of differences in length of leg and body weight among subjects was introduced for determining relationship between muscle strength and ambulatory status. The Z-score represents a deviation from normal development of muscle strength. A cross-sectional and longitudinal study of the Z-score showed that deterioration in development of quadriceps strength of the patients began from 8 years old corresponding to body weight of approximate 25kg. The neurologic level, age of onset of walking and intelligence quotient were closely related to the Z-score. The discriminant function analysis clarified that these four factors were quite useful for assessing and predicting their ambulatory ability.
