Frontal Plane Lower Extremity Biomechanics During Walking in Boys Who Are Overweight Versus Healthy Weight

Purpose: To compare frontal plane lower extremity biomechanics during walking in adolescent boys who were overweight (OW) versus healthy weight (HW). Methods: Fourteen boys (7 considered HW, body mass index for age <85th percentile; age 10.8 +/- 0.7 years; 7 considered OW, body mass index for age >95th percentile; age 12.0 +/- 0.7 years) participated. Three-dimensional kinematic data were collected during walking at self-selected speeds. Group means were compared using Student's t tests (alpha = 0.05). Results: Significant differences were found in timing of rearfoot motions and moments, amplitude of knee motion peaks, timing of knee moment peaks, and timing and amplitudes of peak hip motion and moments. Conclusion: Boys who were OW collapsed into hip adduction and knee valgus during stance and attempted to compensate with rearfoot inversion. Observed differences in frontal plane kinematics during walking suggest that boys who are OW have increased risk of lower extremity musculoskeletal injuries and dysfunction. (Pediatr Phys Ther 2009;21:187-193)