Association Between Calf Muscle Tone, Plantar Surface Area, and Gross Motor Function in Children with Spastic Diplegic Cerebral Palsy

Background: Children diagnosed with spastic diplegic Cerebral Palsy (CP) usually demonstrate hypertonicity of the lower limb muscles which affects the normal alignments and weight reception by the feet. These impairments could be correlated to the limitations in gross motor function such as standing and walking abilities. Understanding these relationships can contribute to developing more effective rehabilitation strategies and improving overall motor outcomes for affected children. Objective: The current study was designed to explore the relationship between plantar surface area, weight distribution on the plantar surface, and gross motor function (namely, standing and walking abilities) in spastic diplegic CP children. Methods: Seventy-one spastic diplegic CP children aged 8– 14 years joined this cross-sectional study. The Person’s correlation coefficient and regression tests were used to assess the correlation between variables, namely, Gross Motor Function (GMFM), Calf Muscle Tone, Plantar surface area (PSA), and Peak pressure on mid and hind feet (PPMF, PPHF, respectively). These variables were assessed using the GMFM-88 scale, Modified Ashworth scale, and foot scan plantar pressure detection system, respectively. Results: The correlation analysis demonstrated a strong to moderate positive correlation between PSA, PPMF, PPHF, and GMFM-D and GMFM-E. Additionally, regression model showed prediction levels equal to 0.791 for the GMFM-D and 0.720 for the GMFM-E categories, respectively. Conclusion: Standing and walking abilities were positively correlated (r ≥ .6) with the increased plantar surface area and higher peak pressure on mid and hind feet in spastic diplegic CP. Future longitudinal studies should investigate changes in gross motor function in relation to improvement in plantar surface area and peak pressure values. Keywords: spastic diplegia, gross motor function, calf muscle, plantar surface area