Research On Drag Sled Training Under Different Speed Loss In Sprint Acceleration Stage

The characteristics of resistance running training are very consistent with the special characteristics of sprint,which has a significant effect on improving the speed and acceleration ability of athletes.In the practical application of sprint training,resistance sleigh training is the most widely used,but in the relevant research at home and abroad,the optimal training load of resistance sleigh is still under discussion.In addition,weight(Kg)and body weight percentage(BW)are selected as the units of measurement in terms of load unit,while differences in athletes’ strength levels are ignored.Therefore,percentage of speed loss(Vdec)is selected as the unit of load in this paper,and the technical and time changes of athletes are observed by SIMI Motion camera.The kinematic influence of drag sled training on the acceleration stage under different speed losses and the training effect after 8-week intervention experiment were explored to find the appropriate training load range of drag sled training in the sprint acceleration stage.Research methods: This study adopts the method of literature,expert interview,experiment and mathematical statistics.The required drag sled loads were determined by literature and expert interviews,which were 10%Vdec,15%Vdec and 20%Vdec,respectively.Eighteen sprinters from the Physical Education College of Hebei Normal University were selected as experimental subjects,including 6 first-level national athletes and 12 second-level national athletes.By random stratified sampling,the athletes were divided into 3 groups(n=6),with 2 first-level national athletes and 4 second-level national athletes in each group.The experiment is divided into two parts:(1)The data collection of the kinematic changes generated by drag sled training in sprint acceleration stage under different speed losses;(2)The 8-week intervention experiment was conducted,and the data of kinematic changes and time changes before and after the intervention experiment were collected.Using SPSS 26.0,paired sample T-test and one-way analysis of variance were conducted to compare the inter-group and intra-group changes of the three groups of drag sled training before and after the experiment,so as to obtain the research results.By combining the kinematic changes in drag sled training and the kinematic and time changes after 8-week intervention experiment,the appropriate load range of drag sled training in the acceleration stage is discussed.Research results:(1)During the drag sled training,the trunk Angle,hip Angle at the moment of departure from the ground,knee Angle at the moment of landing,and ankle Angle at the moment of landing were reduced,and the above angles showed a decreasing trend with the increase of load.The 20%Vdec group had the largest reduction in the above Angle,which was statistically significant.The hip Angle at the moment of landing decreased significantly in the15%Vdec and 20%Vdec groups.(2)After the 8-week intervention experiment,the trunk Angle at 8-12 m was significantly reduced in the 20%Vdec group;The 10%Vdec group significantly increased the hip joint Angle at 28-32 m,while the 20%Vdec group significantly decreased the hip joint Angle at 28-32 m.The 20%Vdec group significantly reduced the ankle Angle during 8-12 m landing.(3)The drag sled training reduced the step length in the acceleration stage,showing a trend of decreasing with the increase of load.The three groups of drag sled training decreased significantly,with statistical significance.After the intervention experiment,in the range of8-12 m,the longer the load is,the more the load increases.On the contrary,in the range of28-32 m,the smaller the load,the larger the increase of step size.(4)After the resistance sled intervention experiment,the speed was accelerated at 0-10 m running,and the improvement was significant in 15%Vdec and 20%Vdec group,both of which had statistical significance.The 20%Vdec group increased the most.However,in0-30 m running time,the improvement of 10%Vdec group and 15%Vdec group was more obvious,with statistical significance,and the improvement of 10%Vdec group was the most.Research conclusion:(1)Through the observation of resistance sled training,it is found that the greater the resistance load is,the greater the reduction of the trunk Angle forward Angle,and after 8weeks of intervention training,the transfer effect on trunk forward technology,the use of20%Vdec load has a positive effect on 0-10 m,but has a negative effect on 0-30 m.(2)10%Vdec,15%Vdec and 20%Vdec resistance sled training can all increase the hip joint Angle during the high acceleration stage(0-10m),and improve the hip extension ability of athletes,among which 20%Vdec group has the greatest improvement;During the low acceleration phase(10-30m),the 10%Vdec and 15%Vdec groups improved hip Angle while off the ground,with the 10%Vdec group showing the greatest improvement.While the20%Vdec group reduced the hip extension Angle while off the ground,this technical change had an impact on the low acceleration phase only through the performance of this phase.(3)The 10%Vdec,15%Vdec and 20%Vdec resistance sled training can all reduce the ankle Angle of sprinters at the moment of landing.The greater the resistance sled load,the greater the reduction of ankle Angle at the moment of landing.Through 8-week intervention training,The 20%Vdec group had a positive transfer effect on the ankle landing technique in the high acceleration stage(0-10),and had a positive effect on the sprint ankle low support technique.(4)The 10%Vdec group had the best improvement effect on the step length in the low acceleration stage(10-30m);The 20%Vdec group had the best improvement on the step length at the high acceleration stage(0-10m),and had a certain improvement on the step frequency.The 15%Vdec group improved the step size of 0-30 m to some extent,but the effect was not as good as that of the other two groups at a specific distance.(5)10%Vdec resistance sleigh training can improve the performance of 10-30 m,20%Vdec resistance sleigh training can improve the performance of 0-10 m stage,15%Vdec resistance sleigh training can improve the performance of 0-30 m,wide applicability,but not strong specificity.