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Abstract
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BACKGROUND: A force-driven harmonic oscillator (FDHO) model reveals 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, than typically developing children 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 that included 26 children with and without DS aged 7-10 years for overground walking and 20 of them for treadmill walking in a lab setting.
METHODS: During overground walking, participants walked at two speeds: normal and their fastest speed. During treadmill walking, participants walked at 75% and 100% of the preferred overground speed. Two load conditions were manipulated for both overground and treadmill walking: no load and ankle load that was equal to 2% of body mass on each side.
RESULTS: Children with DS showed a similar K/G ratio as 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 similar K/G ratio as their healthy peers. LIMITATIONS: The FDHO model cannot specify what muscles are used and how muscles are coordinated for a given motor task.
CONCLUSIONS: Children with DS show similar elastic property of general muscular activity as 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.
Language: en |