Assessment of Medial Gastrocnemius Thickness and Stiffness in Children with Obesity Using Shear Wave Elastography

This study aimed to compare medial gastrocnemius (MG) muscle thickness and shear wave elastography-derived stiffness between children with obesity and healthy-weight controls and to examine associations with metabolic risk parameters.

This cross-sectional study with prospective data collection included 92 children and adolescents, comprising 56 participants with obesity and 36 healthy-weight controls. Anthropometric, laboratory, and metabolic parameters were recorded. MG thickness and stiffness were assessed using standardized ultrasonography and shear wave elastography (SWE) protocols. Between-group comparisons were performed using the independent-samples t test or Mann-Whitney U test, as appropriate. Associations with metabolic parameters were evaluated using Pearson or Spearman correlation analysis, followed by partial correlation analysis adjusted for age, sex, and pubertal stage.

Children with obesity had lower MG stiffness than healthy-weight controls (16.80 ± 3.31 vs. 20.26 ± 3.02 kPa; p < 0.001) and greater MG thickness (2.37 ± 0.40 vs. 1.84 ± 0.38 cm; p = 0.023). After adjustment for age, sex, and pubertal stage, lower MG stiffness remained associated with higher BMI z-score (rp = -0.345, p = 0.001), waist circumference z-score (rp = -0.400, p < 0.001), WHtR z-score (rp = -0.359, p = 0.001), fasting insulin (rp = -0.296, p = 0.005), and HOMA-IR (rp = -0.315, p = 0.003).

These findings indicate that SWE may add information to conventional ultrasonography when evaluating obesity-related alterations in skeletal muscle mechanical properties.