Preliminary Study Of Regression Analysis Of Football Professional College Student's Lower Limb Forces Variable

Objective:At present,relevant studies have pointed out that the athlete's lower extremity strength is directly related with sports performance,especially football,which is based on lower extremity.The vertical jump is one of the most commonly used methods to test lower limb strength,with mature development and high reliability.Therefore,this study will base on testing college football players by using different forms of vertical jumps,and then analyze their lower limb strength and mechanical variables,in order to reveal the correlation between lower limb strength and vertical jump.By means of correlation analysis and stepwise regression analysis,the regression equation of each variable and the existent changing rules will be found out.Eventually,this study will provide scientific and reliable experimental basis for selection,training and competition of college football players.Method:In this study,a total of 67 undergraduate students(35 males and 32 females)from Capital Institute of Physical Education were chosen as subjects for this experiment.First of all,the subjects are required tocomplete CMJ,CJb and CJs three tests on KISTLER force test platform,so as to collect the relevant kinetics of the original data and use the SPSS 22.0 data for independent sample T test,Pearson Correlation-analysis and stepwise regression analysis on the lower extremity of the subjects,and ultimately to find the regression equation of each variable and the existent changing rules.Result:(1)In the CMJ vertical jump form,there is a significant difference between instantaneous force value and fast muscle fiber ratio between male and female soccer players(P<0.05).The significant difference exists in take-off height,squat height,power and initial take-off speed(P<0.01).The instantaneous force index(R~2=0.526 and 0.62,respectively)of male and female soccer players can be greatly predicted by power and early take-off.(2)In the CJb longitudinal jump form,there is a significant difference between the instantaneous force value and height fatigue index between male and female soccer players under(P<0.05).The significant difference exists in average jump height,average power and maximum take-off height(P<0.01).The average instantaneous force index(R~2=0.852)of male soccer players can be greatly predicted by average power and average contact time.Average contact time and average power and average height can greatly predict the average instantaneous force index of female soccer players(R~2=0.844).(3)In the CJs vertical jump form,there is a significant difference in average contact time between male and female soccer players(P<0.05).The significant difference exists in average vertical jump height,average power,leg stiffness and maximum vertical jump height(P<0.01).Average vertical jump height and average contact time,lower extremity balance index can be used to greatly predict the average power index of male and female soccer players(R~2=0.949 and R~2=0.953,respectively).Conclusions:(1)In the CMJ vertical jump form,there is a very significant positive correlation between power and instantaneous force,and there is also a very significant positive correlation between initial jump speed and instantaneous force.The establishment of regression equation model used for the power and jump speed can significantly predict the instantaneous force value.(2)In the CJs vertical jump form,there is a very significant positive correlation among the average power,average take-off height and lower extremity balance index.while there is a significant negative correlation between the average power and the average contact time.Establish a regression equation model,you can use the average height of the jump,lower extremity balance index and average contact time to significantly predict the average power.(3)In the vertical jump form of CMJ,CJb and CJs,the power has a very significant positive correlation with the height of take-off.Improving the power of lower extremity muscles,i.e,explosive force,helps to improve the vertical jump height.(4)In the vertical jump mode of CJb and CJs,the power has a very significant negative correlation with the contact time and above moderate level,which shows that in the process of continuous vertical jump,the length of contact time will affect the performance of next vertical jump burst force.(5)In the vertical jump form of CMJ and CJb,there is no significant correlation between instantaneous force value and take-off height,which shows that the size of power is not a direct determinant of vertical jump ability.However,there is a significant correlation between the vertical jump height and power,which indicates that the power of lower limb muscles is an important factor affecting the vertical jump height.(6)There is a very significant and high correlation between speed endurance and voluntary effort index.Legs stiffness and contact time has very significant negative over-medium correlation.Leg balance index and power,take-off height,leg stiffness has very significant moderately positive correlation.Power and fast muscle fiber ratio presents a very significant correlation.