How do changes in motor capacity, motor capability, and motor performance relate in children and adolescents with...

To investigate the relations between changes in motor capacity (can do, in standardized environment), motor capability (can do, in daily environment), and motor performance (does do, in daily environment) among children with cerebral palsy (CP).

Prospective longitudinal study. After baseline measurements (at the age of 18 mo, 30 mo, 5 y, 7 y, 9 y, 11 y, or 13 y), 2-year follow-up measurements were performed. Change scores were calculated, and Pearson correlations were used for change score relations.

Outpatient clinic.

Toddlers, school-age children, and adolescents with CP (N=321; 200 boys, 121 girls). Levels of severity according to the Gross Motor Function Classification System included level I (42%), level II (15%), level III (17%), level IV (13%), and level V (13%).

Not applicable.

Change in motor capacity was assessed with the Gross Motor Function Measure-66. Changes in motor capability and motor performance were assessed with the Pediatric Evaluation of Disability Inventory using the Functional Skills Scale and Caregiver Assistance Scale, respectively.

Within the total group, change score correlations were moderate (.52-.67) and significant (P<.001). For age groups, correlations were significantly higher in toddlers than school-age children and adolescents. For severity levels, correlations were significantly higher in children at level III than level I, IV, and V.

Results imply that change in motor capacity does not automatically translate to change in motor capability and change in motor capability does not automatically translate to change in motor performance. Results also show different relations for clinically relevant subgroups. These are important insights for clinical practice because they can guide evidence-based interventions with a focus on activities.