Age-Related Changes in Virtual Pivot Point Position and Variability During Pediatric Gait Development.

Area of Science:

• Biomechanics
• Developmental Pediatrics
• Human Locomotion

Background:

• Ground reaction forces (GRFs) during adult walking intersect near the center of mass (CoM) at the virtual pivot point (VPP).
• The VPP is theorized to aid upper body stabilization during locomotion.
• The developmental trajectory of the VPP in early childhood remains largely unexplored.

Purpose of the Study:

• To investigate age-related differences in VPP position and variability during walking in typically developing children.
• To analyze changes in GRF focusing across different childhood age groups.

Main Methods:

• Markerless motion capture and force plates were used to collect kinematic and kinetic data.
• 29 children were divided into three age groups: 1 year, 2-3 years, and 10-15 years.
• VPP position, variability, and GRF focusing (R² ) were analyzed in the sagittal plane during single support.

Main Results:

• GRFs consistently focused on a VPP across all age groups (R² > 0.95), with no significant differences in focusing.
• Significant age-related differences were observed in VPP position and variability.
• Normalized vertical VPP position increased with age, and toddlers sometimes exhibited VPP at or below the CoM.

Conclusions:

• GRF focusing is present in toddlers with independent walking ability.
• VPP characteristics, including position and variability, undergo significant developmental changes throughout childhood.
• Shifting VPP position and reduced variability suggest evolving gait mechanics and trunk stabilization strategies.