Related Experiment Videos
Duration of muscle activity during standing in normally and slowly developing children
Insights
Children with delayed motor development show different muscle activity patterns during standing compared to typically developing children. Trunk muscles are more active in delayed development, especially with arm movements.
Area of Science:
- Motor control
- Developmental pediatrics
- Biomechanics
Background:
- Adults exhibit consistent muscle activity patterns during standing.
- Understanding pediatric motor development is crucial for identifying developmental delays.
Purpose of the Study:
- To investigate muscle activity duration patterns during quiet standing in children aged 4-10.
- To compare these patterns between children with normal and delayed motor development.
- To assess the impact of superimposed arm movements on these patterns.
Main Methods:
- Electromyography (EMG) recorded muscle activity in Gastrocnemius, Tibialis Anterior, and Erector Spinae.
- Thirty-three children (4, 6, 8, 10 years) were screened and classified by motor development level.
- Children performed quiet standing and standing with superimposed shoulder abduction.
Main Results:
- Children with delayed motor development showed greater trunk muscle (Erector Spinae) activity duration relative to leg muscles.
- Typically developing children had a more balanced distribution of activity between trunk and leg muscles.
- Both groups increased Erector Spinae activity during arm movement, but leg muscle activity patterns differed.
Conclusions:
- Quiet standing muscle activity patterns differ between typically developing and motor-delayed children.
- Motor development level influences postural control strategies in children.
- Leg muscle activity patterns during standing are distinct in children with motor delays, even when accommodating upper limb tasks.
Abstract:
Research in motor control indicates that there are fixed patterns of activity which occur in certain muscle groups involved in standing in adults. The purpose of this study was to assess patterns of duration of muscle activity during quiet standing with and without superimposed arm movement in young children with normal and delayed motor development. Thirty-three children 4, 6, 8 and 10 years of age were screened for level of motor development and classified as either normally or slowly developing. Children performed two tasks: standing and standing with a superimposed 90 degree shoulder abduction movement. Using surface electrodes, EMG activity was monitored in Gastrocnemius, Tibialis Anterior and Erector Spinae muscle groups. The percentage of time activity was present in individual muscle groups was analyzed as a function of age and developmental level. Results indicated that quiet standing in children with delayed motor development was characterized by greater duration of activity in trunk than in leg muscles while in normal children, there was a more equal distribution of muscle activity between the legs and trunk. Both groups of children accommodated superimposed arm movement by increasing the percentage of time Erector Spinae activity was present. Patterns of duration of muscle activity in the legs were, however, different for the two groups of children.