Key Measures: Primary outcome measures in the study include the Gross Motor Function Measure and an observational measure of toy contacts for sitting and reaching, and the Individual and Growth Development Indicators (Early Problem Solving Indicator) and Bayley Scales of Infant and Toddler Development -Third Edition for problem solving and global development. Secondary measures include additional measures of postural control and reaching, child and family characteristics, and fidelity of implementation (logs and checklist).