Lower-limbs’ muscle coordination mechanism of healthy preschoolers while walking across obstacles

The obstacle-crossing task was a complex gait task, it required an advance predict of the obstacle for posture adjustment and accurate control of bilateral legs to ensure crossing obstacle successfully. By monitoring the activated intensity and duration of muscles in this process, we could assess preschooler’s motor ability objectively and quantitatively, as well as disclose their potential pathogenesis quality eventually. 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, our purpose of this study was first to portray the patterns and characteristics of lower limb muscles of healthy preschoolers while OW motion and then to insight their muscles’ coordination mechanism. 35 healthy preschoolers and 35 healthy adults’ lower limb’s sEMG were collected while left and right OW and four muscle groups (Tibialis Anterior, Lateral Gastrocnemius, Rectus Femoris, and Biceps Femoris) were included. 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. Preschoolers would adjust the gait by changing the activation time and activation rate to fulfill the obstacle crossing tasks, but they also showed variations when contrasting to adults. Further, synergy between muscles in leg and thigh were also found. Although preschoolers performed well enough to finish the OW tasks, ability gaps were still apparent to adults. Hence, with the help of a deeply recognizable muscle coordination mechanism in OW, we can effectively identify motor dysfunction in the lower limbs of preschool children. • Lower limb’s sEMG of preschoolers while obstacle crossing was studied. • Preschoolers adjusted gait by changing the activation time and rate of muscles. • Synergy of the thigh and calf muscles were to ensure safety clearance while OW. • Enhanced mechanism was sequential activation and co-activation of muscles. • Limited in muscle strength, preschoolers needed further muscle development.