Study On The Relationship About The Characteristics Of Lower Limb Reactive Force And The Speed Quality In Men Aged 10-12

Objective:The purpose of this study was to:1)investigate the correlation between the speed quality and the reactive force of the lower limbs in men aged 10-12 years.2)explore the characteristics and differences of the lower limbs’ speed quality and response strength between the subjects of different age groups.Subjects:Sixty five 10-12 years old men were recruited from high-level track and field school,Luoyang,China,including 18 10-year-old men(10.268±0.373),25 11 year old men(11.218±0.311)and 22 12-year-old men(12.136±0.343).Methods:In this study,the speed quality and three kinds of vertical jumps of the subjects were tested by experimental method.The speed diathesis test consisted of a 30-m run,a 30-m run between walks,and a 60-m run.The vertical jump test includes Squat Jump(SJ),Counter Movement Jump(CMJ)and Deep Jump(DJ)test at heights of 20,30 and 45cm.The correlation analysis was made between the each index of subjects’ speed quality and the vertical jump,and the differences of the indexes of different age groups were discussed by T-test.Research results:(1)The three speed qualities are negatively correlated with the impulse,peak power and jump height of SJ and CMJ.It also has negative correlation with impulse,peak power,RSI and RSR of DJ.(2)Men at different ages from 10-12 years old showed significant differences in the impact,power index of SJ(P<0.05).There were significant differences among different age groups in the maximum force,jump height,RFD,RSImod,RSR index of CMJ(P<0.05),in the jump height,RSI index of 20 cm DJ(P<0.05),in the jump height and jump time for 30 cm DJ(P<0.05),and none of the indicators between the three groups with 45 cm DJ.(3)There were significant differences among different age groups in the maximum force,impulse and peak power of DJ at different heights(P<0.05),and there are also significant differences between 10-year-old group and 12-year-old group in the RFD index(P<0.05).(4)In the difference analysis of SJ and CMJ indexes at the same age,there were no significant differences(P>0.05)except for the RFD at the age of 10 and 12 years as well as the maximum force value at the age of 11 years.(5)10-12-year-old men’s muscle elastic energy utilization ability in SJ is significantly better than that in DJ at three heights(P<0.05).The utilization rate of skeletal muscle elastic energy in DJ at three different heights was negative,but it increased as the jump depth increased.(6)The DJ scores of 11-year-old group were better than those of 10-year-old group and 12-year-old group.Combined with BMI index,it was found that BMI index of 1012-years old men had significant correlation with touchdown time and RSR of DJ(P>0.05).Research conclusions:(1)There are significant differences in lower limb reactive force between different age groups of men aged 10-12.The difference of speed quality between adjacent age groups is small,but the overall trend is increasing.(2)Three vertical jump performances can reflect the speed quality well,and the reactive force will have an impact on the speed quality.(3)Poor concession work ability will affect SSC exercise ability,and is not conducive to the utilization of elastic energy of lower limb skeletal muscle.The development of concession work ability should precede the development of SSC exercise ability.For men with poor concession work ability of lower limb muscles at this age,DJ is not suitable as a training method to develop SSC ability.(4)The body shape of a 10-12 year old man may influence the performance of deep jump.