Related Experiment Video
Updated: Aug 18, 2025
Sit-to-stand-and-walk from 120% Knee Height: A Novel Approach to Assess Dynamic Postural Control Independent of Lead-limb
Published on: August 30, 2016
Lower-limbs' muscle coordination mechanism of healthy preschoolers while walking across obstacles
Jingjing Li1, Quting Huang2, Bo Xu1
1National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, PR China.
Insights
Preschoolers use muscle adjustments for obstacle crossing, but show differences compared to adults. Understanding these muscle coordination patterns can help identify lower limb motor dysfunction in children.
Area of Science:
- Biomechanics
- Motor Control
- Developmental Pediatrics
Background:
- Obstacle-crossing is a complex gait task requiring predictive posture adjustment and precise leg control.
- Monitoring muscle activity during obstacle crossing offers objective assessment of preschoolers' motor abilities and potential developmental issues.
Purpose of the Study:
- To characterize lower limb muscle patterns during obstacle-walking (OW) in healthy preschoolers.
- To assess the muscle coordination mechanisms employed during OW in this age group.
Main Methods:
- Collected surface electromyography (sEMG) from lower limb muscles of 35 preschoolers and 35 adults during OW.
- Analyzed sEMG variables including activation time, duration, and rate of change.
- Used paired sample t-tests to compare preschoolers and adults.
Main Results:
- Preschoolers demonstrated gait adjustments via altered muscle activation timing and rate during OW.
- Significant differences in sEMG variables were observed when comparing preschoolers to adults.
- Synergistic muscle activation patterns were identified in the leg and thigh.
Conclusions:
- While preschoolers can complete OW tasks, performance gaps exist compared to adults.
- Recognizing muscle coordination mechanisms in OW is crucial for identifying lower limb motor dysfunction in children.
Research Background:
The obstacle-crossing task is a complex gait task, it requires an advance predict of the obstacle for posture adjustment and accurate control of bilateral legs to ensure crossing the obstacles successfully. By monitoring the activated intensity and duration of muscles in this process, preschoolers' motor ability could be assessed objectively and quantitatively, as well as disclose their potential pathogenesis quality eventually.
Scientific Question:
what are the patterns and characteristics of lower limb muscles when they are facing the obstacle-crossing walking (OW) tasks, and how they coordinate their individual muscle or muscle groups of lower-limbs muscles while walking across obstacles? Thereby, the purpose of this study was first to portray the patterns and characteristics of lower limb muscles of healthy preschoolers while OW motion and second to assess the muscles' coordination mechanism.
Method:
35 healthy preschoolers and 35 healthy adults' lower limbs' surface electromyography (sEMG) were collected while left and right OW and four muscle groups (Tibialis Anterior, Lateral Gastrocnemius, Rectus Femoris, and Biceps Femoris) were recorded. sEMG variables such as Muscle Activation Time, Total Duration of Activity Time, Average Muscle Activation Rate, and Average Rate of Change were calculated. The paired sample-t-test was used to explore the differences of sEMG variables between preschoolers and adults when obstacle-crossing.
Results:
Preschoolers would adjust the gait by changing the activation time and activation rate to fulfill the obstacle crossing tasks, but they also showed variations by contrasting to adults. Further, synergy between muscles in leg and thigh were also found.
Conclusion:
Although preschoolers performed well enough to finish the OW tasks, ability gaps were still apparent when compared to adults. Hence, with the help of a deeply recognizable muscle coordination mechanism in OW, motor dysfunction in the lower limbs of preschool children can be effectively identified.
Related Concept Videos
01:24Muscle Coordination and Action
Agonists
Agonist muscles, often called prime movers, are the primary muscles responsible for producing a specific movement....
01:18Hierarchy of Motor Control
01:16Hydraulic Jump: Problem Solving
01:15Kinematic Equations: Problem Solving
01:11Direct Motor Pathways
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and...
01:17Rolling Resistance: Problem Solving