This observational study will evaluate whether a smartphone's built-in accelerometer can provide accurate and repeatable measurements of walking in children with unilateral spastic cerebral palsy.

Thirty-five children aged 6 to 12 years will complete two walking trials along a 10-meter indoor walkway at their usual comfortable speed. During each trial, a smartphone will be secured over the lower back at the L4-L5 level to record body acceleration using the Phyphox application. At the same time, a video camera will record the child's walking for analysis using Kinovea software.

Measurements obtained from the smartphone will be compared with measurements obtained from video analysis. The study will assess walking velocity, cadence, stride timing, and gait asymmetry. The two repeated walking trials will also be used to determine whether the smartphone measurements are consistent when the test is repeated during the same session.

The study does not involve any treatment or change to the child's usual medical or physical therapy care. The purpose is to determine whether smartphone-based gait assessment may be a practical, low-cost method for evaluating walking in children with unilateral spastic cerebral palsy.