Movement-Based Priming: A Clinical Trial on the Effect of Cross-Training on Locomotor Abilities of Children with Unilateral Cerebral Palsy

Background: Children with unilateral cerebral palsy (UCP) frequently experience limitations in locomotor abilities, attributable to a complex interplay of factors including muscle weakness and reduced joint mobility. Movement-based priming, such as cross-training (CT), has emerged as a potential intervention to enhance motor function in children with UCP. However, evidence of its efficacy remains limited. Objective: This study aimed to investigate the effect of CT—specifically, a strengthening-based unilateral priming protocol—on muscle strength, joint mobility, and locomotor abilities in children with UCP. Methods: Thirty-six children with UCP were enrolled in a randomized controlled trial. Participants were randomized into two groups: the control group (n = 18; underwent a tailored physical rehabilitation program) and the CT group (n = 18; participated in a CT program incorporating unilateral priming exercises targeting the less-affected lower followed by the same rehabilitation program administered to the control group). Dorsiflexor strength, ankle joint mobility, and locomotor ability assessed via the 10 m walk test (10 mWT), 6 min walk test (6 MWT), and timed up-and-go test (TUG) were evaluated pre- and post-intervention. Results: Significant moderate-to-large between-group differences were observed in dorsiflexor strength (p = 0.032, partial η² = 0.128), ankle mobility (p = 0.016, partial η² = 0.159), and locomotor ability (10 mWT [p = 0.017, partial η² = 0.157]; 6 MWT [p = 0.004, partial η² = 0.222]; TUG [p = 0.047, partial η² = 0.111]). The CT group demonstrated superior improvements concerning all outcomes. Conclusions: Unilateral priming through strengthening-based CT is a viable intervention for enhancing motor function in children with UCP, providing a promising complement to the current rehabilitation protocols.