Study On The Influence Of Small-sided Games With Different Field Area On The Change Of Direction Ability Of U11-U12 Adolescents

Objectives:Adolescents’the ability to change of direction is an important physical quality in football matches.Having good the ability to change of direction can improve their performance in matches.At present,the training of the ability to change of direction mainly adopts the training methods of track and field,such as speed training,strength training,etc.,and the training of the ability to change of direction cannot be better transformed into competition ability.As an ideal combination of ball training,small-sided games can not only meet the competition needs of adolescents,but also improve their ability to change of direction.Secondly,as one of the important factors affecting small-sided games,there are few studies on whether there is a difference in the influence of small field training with different field areas on the ability to change direction.In this study,twenty-four adolescents,who are 11-12 year old and from Aizhai Pijie Primary School in Linqing city were trained and analyzed on their physical indicators such as the ability to change of direction,Counter Movement Jump(CMJ)and 10 m straight sprint speed through 8-week small-field football training in different field areas.In order to provide theoretical and empirical basis for scientific and efficient training of adolescents’the ability to change of direction,this paper studies whether there is difference in the influence of different field area on adolescents’the ability to change of direction and explores the reasons why small field training affects adolescents’the ability to change of direction,and promotes the progress of research theory on small-sided games and the ability to change of direction.Methods:This paper adopts the methods of literature,expert interview,experiment and mathematical statistics to study the influence of small field training in different field areas on the directional ability of 11-12 years old teenagers.Twenty-four adolescents from the school football team of Aizhai Pijie Primary School in Linqing were selected and divided into Small group(n=8),Moderate group(n=8),Large group(n=8)(hereinafter referred to as group S,group M,group L)by S-type grouping.Group S received 8 weeks of small-field football match training with a per capita field area of75 m~2,group M received 8 weeks of small-field football match training with a per capita field area of 125 m~2,and Group L received 8 weeks of small-field football match training with a per capita field area of 175 m~2.Before and after the experiment,all subjects were tested for the change of direction ability,CMJ height,10 m straight sprint and so on.Shapiro-Wilk test was used to analyze whether the three groups of test indicators were in line with normal distribution.One-way ANOVA was used to analyze whether there was any difference in pretest data of group S,group M and group L.Then,repeated measure variance was used to compare data before and after intervention,and effect sizes were compared.Secondly,covariance analysis is carried out for indexes with interactive effects.Results:(1)According to Shapiro-Wilk test analysis,the indicators of height,weight,Illinois test,“505”test,“T”type running test,CMJ and 10 m straight Sprint test of subjects in the three groups all conform to normal distribution.(2)According to one-way ANOVA,there were no significant differences in height,weight,reversing ability,CMJ height and 10 m straight sprint indexes in group S,group M and group L before intervention(P>0.05).(3)According to repeated measure ANOVA,the Illinois test,"505"test,"T"run test and 10 m straight sprint test had significant interaction effect in time*group(P<0.05),but there was no interaction effect in CMJ height(P>0.05).(4)By effect size analysis,it was found that the effect size of group S in Illinois test,“505”test,"T"type running test and 10 m straight sprint test were all larger than that of group M and group L.(5)Covariance analysis showed that 10 m straight sprint had a significant impact on"T"type running test(P<0.05).Conclusions:(1)After 8 weeks of Small-sided games training with different field areas,adolescents’ability to change of direction during the sensitive period can be significantly improved,and the small-field training with small field area can improve adolescents’ability to change of direction more significantly.(2)After 8 weeks of Small-sided games with different field areas,the short distance sprint ability of adolescents can be significantly improved,but there is no significant impact on the explosive vertical jumping ability of adolescents(3)Small-sided games training can improve the ability to change of direction by improving the speed of short distance sprint,muscle strength of lower limbs and changing direction technology.