A Longitudinal Study On The Development Of Hopping In Preschool Children

PurposeHopping is a late-developed and difficult-to-finish movement in basic motor skills,which can reflect the leg strength,coordination,and balance of children.The current research on hopping cannot objectively reflect the law of movements development.Based on above,this longitudinal study explores the characteristics of longitudinal changes in kinematic indexes at various ages,and summarizes the law of hooping development in 3-6 years old children according to those characteristics of changes.MethodsForty-eight 3.5-year-old children in Beijing were selected as the follow-up test subjects in this study.The follow-up time was 3 years,and tests were performed every 6 months for a total of 6 tests.The Qualisys infrared light spot capture system was used to shoot the movements of hopping.Visual 3D software was used to analyze the kinematics data.Statistical methods are normal distribution test and repeated measurement analysis of variance which are used to compare the similarities and differences between children of all age groups and summarize the development law of hopping of children.Results(1)Spatio-temporal characteristics: Hopping cycle,maximum ground clearance,and jumping frequency had no significant changes with age.The proportion of buffer period and kick-extension period decreased significantly with age(p <0.05).The proportion of suspension period increased significantly(p <0.05),and the jump distance and jump distance after normalization both increased significantly(p <0.05).(2)Characteristic moment joint angle change characteristics: hip flexion and extension angle when the toe of the supporting side lower limb is off the ground,hip flexion and extension angle,knee flexion and extension angle when the toe touches the ground,hip flexion and extension angle,ankle flexion and extension angle,and ankle The change of the abduction angle and the flexion and extension angle of the hip joint at the point when the toe is off the ground again is significant at the age of4.0-6.0 years(p <0.05);Significant(p <0.05);there was no significant difference in the angles of the joints at different characteristic moments of the upper limbs with age.(3)The vertical change trend of joint angle during the exercise cycle: With the increase of age,the overall trend of the hip,knee,and ankle angles of the supporting side of the lower limbs has not changed significantly;the hip flexion angle of the swing leg of a 4.0-year-old child is significantly higher than other ages,and it decreases significantly at 4.5 years.The overall fluctuation is not large,and the amplitude of the curve gradually increases after 5.0 years of age.As the age increases,the curve of knee flexion angle gradually becomes flat,and the shoulder abduction angle gradually decreases.(4)Coordination of movement: During the period of 4.0 to 5.0 years,the upper limbs swing slightly back and forth in the shoulder joints but there is no obvious trend.Starting at 5.5 years old,the upper limbs of children have a swinging trend in the same direction as the swinging leg and opposite to the swinging leg of the support leg.Conclusion(1)Hopping movement gradually develops towards a more mature direction with age.It shown as: the proportion of flight part and the distance are increase;the swinging leg gradually lowers without raised to prevent falling,and begins to swing for assistance of jumping.Upper limb protection gradually disappears,swinging assistance begins to appear in the upper arm,and balance and coordination are improved.(2)Through follow-up research and analysis,according to the difference in the development speed of hopping between different ages and the changes in movement patterns,it is initially concluded that the development of hopping in early childhood needs to go through three stages: the first stage is 3.5 years old to 4.0 years old,while the balance ability of children is improved and start to finish hopping;the second stage is 4.5 to 5.5 years old,while the jumping direction changes from upward to forward,however,this stage develops slowly,and the changes of each indicator are less different with age;the third stage is 6.0 years old,while upper limb protection is disappear,young children have the ability of continuous forward hopping,and pay attention to the economics and coordination of development movements.6 years old is the beginning of the further development of hopping,at this age,it has not yet matured.