Clinically speaking, the major role played by children's preferences suggests that children's participation can be encouraged by explicit consideration of children's motives for engaging in activities.We found that the intensity of children's participation in recreational, active physical, and social activities declined as children aged over the 3-year study period. The intensity of their involvement in skill-based and self-improvement activities did not show appreciable change, perhaps because these activities are more parent controlled, and parents are more likely to ensure that these activities continue. Significant predictors of change were found only for recreational and active physical activities. Overall, the findings indicated that factors associated with change in participation intensity are dependent on the type of activity and vary as a function of children's gender and age.