Biomechanical characteristics of lower limb gait waveforms: Associations with body fat in children

Background: Childhood obesity is associated with musculoskeletal dysfunction and altered lower limb bio- mechanics during gait. Few previous studies have explored relationships between childhood obesity measured by body fat and lower limb joint waveform kinematics and kinetics. Research question: What is the association between body fat and hip, knee and ankle joint angles and moments during gait and in 7 to 11 year-old boys? Methods: Fifty-five boys participated in the study. Body fat was measured by air displacement plethysmography. Hip, knee and ankle 3D waveforms of joint angles and moments were recorded during gait. Principle component analysis was used to reduce the multidimensional nature of the waveform into components representing parts of the gait cycle. Multiple linear regression analysis determined the association between the components with body fat. Results: Higher body fat predicted greater hip fl exion, knee fl exion and knee internal rotation during late stance and greater ankle external rotation in late swing/early stance. Greater hip fl exion and adduction moments were found in early stance with higher body fat. In mid-stance, greater knee adduction moments were associated with high body fat. Finally, at the ankle, higher body fat was predictive of greater internal rotation moments. Significance: The study presents novel information on relationships between body fat and kinematic and kinetic waveform analysis of paediatric gait. The findings suggest altered lower limb joint kinematics and kinetics with high body fat in young boys. The fi ndings may help to inform research in to preventing musculoskeletal co- morbidities and promoting weight management.