Nine children with spastic hemiplegic cerebral palsy underwent 24 sessions of wrist muscles strengthening in the extended wrist range aided by electrostimulation. Isometric strength of flexors and extensors was registered in three wrist positions (30 degrees of flexion, neutral, and 30 degrees of extension) to infer on angle-torque curves. Passive stiffness of wrist flexors and wrist flexion angle during manual tasks and hand function were also documented. Significant strength gains were observed at 30 degrees of wrist extension for flexors (p= 0.029) and extensors (p= 0.024). No gains were observed at 30 degrees of flexion. The difference in extensor strength between the three test positions changed after intervention (p< 0.034), suggesting a shift in the angle-torque curve. No changes were observed in passive stiffness (p= 0.506), wrist angle (p< 0.586), or hand function (p= 0.525). Strength training in specific joint ranges may alter angle-torque relationships. For functional gains to be observed, however, a more aggressive intervention and contextualized task training would probably be needed.