Abstract
Learning about the dynamics of early childhood development in the context of poverty and malnutrition is an effective way to identify the periods of highest psychosocial vulnerability and the role of timing in the differential responsivity of young children to interventions. Motor activity under natural conditions is one area of development that requires further study because of its biological and psychological developmental importance. This paper presents an estimate of the development function of motor activity among poorly nourished children whose ages ranged from 12 to 30 months. It also focuses on the longitudinal relationship between the nature, level of motor development, and intensity of motor actions, on the one hand, and physical growth, dietary intake, and motor activity, on the other.
Two cohorts (12 and 18 months old) of rural West Javanese children were studied. Motor activity, energy intake, physical growth, and motor development were measured every two months. A motor activity score was calculated based on the estimated energy cost and intensity of each activity and their frequency and duration during each of the periods of observation. Intensity was classified according to a three-point scale (high = 1.25, moderate = 1.0, low = 0.75). the Bayley Scale of Motor Development and a scale of motor milestones were used to assess motor development (e.g., crawling, creeping, walking, and running).
The developmental function of activity was curvilinear. It showed a moderately fast acceleration from 12 to about 18 to 20 months; at that point the curve reached a plateau. the functions of growth and energy intake were linear. the average motor behaviour of these children was characterized by its low level of intensity. Although the relationship between motor activity and motor development was relatively close up to about 20 months, thereafter the motor activity and motor development scores were independent of each other. the changes in activity level were primarily determined by a significant decline of involvement in activities having a low energy cost and an increase in activities having moderate or high energy cost. the decline of motor activity observed at 18 months is reminiscent of the decline in growth velocity observed during the first six months of life among malnourished children. It is plausible that the pattern of activity observed could be explained by either contextual or cultural factors.