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Walking dynamics in preadolescents with and without Down syndrome
Jianhua Wu1, Matthew Beerse2, Toyin Ajisafe3
1J. Wu, PhD, Department of Kinesiology and Health, Georgia State University, 125 Decatur St, Atlanta, GA 30302 (USA). jwu11@gsu.edu.
Insights
Children with Down syndrome (DS) exhibit similar muscle elasticity to peers during walking. External ankle load aids DS children in matching peer muscle activity on treadmills, especially at faster speeds.
Area of Science:
- Biomechanics and Motor Control
- Developmental Pediatrics
Background:
- The force-driven harmonic oscillator (FDHO) model quantifies general muscular activity during locomotion.
- Understanding the elastic properties of muscle in children with Down syndrome (DS) is crucial for gait analysis.
Purpose of the Study:
- To compare the K/G ratio, a key FDHO variable, between children with DS and typically developing peers.
- To examine the adaptability of the K/G ratio in children with DS across different walking speeds, loads, and treadmill conditions.
Main Methods:
- A cross-sectional study involving 26 children (aged 7-10) with and without DS.
- Overground and treadmill walking trials were conducted under varying speeds and external ankle load conditions (0% and 2% body mass).
Main Results:
- Children with DS demonstrated a K/G ratio comparable to controls during overground walking, increasing with speed.
- On the treadmill, children with DS had a lower K/G ratio at faster speeds without load, but external ankle load normalized this ratio.
Conclusions:
- The elastic properties of general muscular activity in children with DS are similar to typically developing peers during overground walking.
- External ankle loading can enhance muscular activity in children with DS, enabling them to match peer performance on treadmills at higher speeds.
Background:
A force-driven harmonic oscillator (FDHO) model reveals the elastic property of general muscular activity during walking.
Objective:
This study aimed to investigate whether children with Down syndrome (DS) have a lower K/G ratio, a primary variable derived from the FDHO model, compared with children with typical development during overground and treadmill walking and whether children with DS can adapt the K/G ratio to walking speeds, external ankle load, and a treadmill setting.
Design:
A cross-sectional study design was used that included 26 children with and without DS, aged 7 to 10 years, for overground walking and 20 of them for treadmill walking in a laboratory setting.
Methods:
During overground walking, participants walked at 2 speeds: normal and fastest speed. During treadmill walking, participants walked at 75% and 100% of their preferred overground speed. Two load conditions were manipulated for both overground and treadmill walking: no load and an ankle load that was equal to 2% of body mass on each side.
Results:
Children with DS showed a K/G ratio similar to that of their healthy peers and increased this ratio with walking speed regardless of ankle load during overground walking. Children with DS produced a lower K/G ratio at the fast speed of treadmill walking without ankle load, but ankle load helped them produce a K/G ratio similar to that of their healthy peers.
Limitations:
The FDHO model cannot specify what muscles are used or how muscles are coordinated for a given motor task.
Conclusions:
Children with DS show elastic property of general muscular activity similar to their healthy peers during overground walking. External ankle load helps children with DS increase general muscular activity and match their healthy peers while walking fast on a treadmill.
