Carry-Over Effects of Lower Limb Cross-Training Priming on Upper Limb Function in Children With Unilateral Cerebral Palsy

PURPOSE: The purpose of this randomized controlled trial was to investigate the potential carry-over effects of a 6-week lower limb strengthening-based cross-training (CT) priming protocol, added to standard physical rehabilitation, on affected upper limb function in children aged 6-8 years with unilateral cerebral palsy (UCP), compared to standard physical rehabilitation alone. BACKGROUND: Children with unilateral cerebral palsy (UCP) experience motor impairments affecting both lower and upper limbs, significantly impacting functional independence. While rehabilitation often targets specific limbs, interventions may induce broader neuroplastic changes. Movement-based priming, particularly strengthening-based cross-training (CT) targeting the less-affected limb, has shown promise for improving contralateral lower limb function in UCP, likely via cross-education mechanisms involving central nervous system adaptations. However, it remains largely unexplored whether such lower limb-focused priming interventions can induce secondary "carry-over" effects, positively influencing the function of the ipsilaterally affected upper limb through potential mechanisms like widespread neural adaptations or improved postural stability. Addressing this gap is crucial for understanding the holistic impact of priming interventions and optimizing rehabilitation strategies. HYPOTHESES: There will be no statistically significant difference in the improvement of affected handgrip strength, grasping skills and functional UL Outcome Measure between children receiving lower limb CT priming plus standard rehabilitation and those receiving standard rehabilitation alone over the 6-week intervention period. RESEARCH QUESTION: Does the addition of a 6-week lower limb strengthening-based cross-training priming protocol to standard physical rehabilitation result in significantly greater improvements in affected upper limb function (specifically handgrip strength and grasping skills) compared