Effect Of Anticipation On Lower Extremity Kinematics During Side-cutting For Collegiate Basketball Player

Objective: Side-cutting is a high-risk action of basketball players’ ACL injury,especially when the players respond quickly to sudden changes in the outside environment,such as in order to get rid of the sudden action from opponents or receive the ball from the teammates,which external stimuli all occur under uncertain or unanticipated conditions.In the past,we used to test and analyze the movement of athletes with sport biomechanics in the anticipated state in the laboratory.However,the test in this anticipated state cannot completely reflect the actual situation of athletes in the competition environment.Therefore,this study will simulate the different anticipated state of the competition environment,exploring the effect of the anticipated state on the lower extremity kinematics of basketball players at different levels when they complete the side-cutting action,and provide the basis for the design of injury prevention training program for basketball players.Method: This study selects 17 high-level basketball players from colleges(both athletes with the National Basketball Athlete Certificate and above)and 25 general-selected basketball college students as research object.This method is adopted to 8-lens Nokov(China)infrared light spot motion capture system(acquisition frequency: 200Hz),collecting the Kinematics data of the lower extremity about joint when the subjects complete the side-cutting action in the anticipated and unanticipated states.Cortex-64 5.5.0 analysis software is used to process and analyze the Kinematics data to obtain the three-dimensional angle of each joint of the lower extremity.Two-Way ANOVA with 2 × 2 mixed design is used to analyze the anticipated state and the effect of basketball players with different levels on the Kinematics data from each joint of the lower extremity.After that,t-test and independent sample t-test compare the differences between anticipated state and the level of exercise,respectively.All statistical analysis was performed with SPSS 22.0 software,in which the significance criterion is set to a class of error probability and it cannot be more than 0.05.Results: Compared with the anticipated state,the subjects in the two groups with different exercise levels showed smaller hip flexion angle(p=0.007)and higher center of gravity(p<0.001)in the unanticipated state.At the moment of landing,regardless of the level of exercise compared with the anticipated state,the hip flexion angle(p=0.007)and the relatively high center of gravity(p<0.001)were shown when the side-cutting action was completed in an unanticipated state.At the moment of landing,regardless of the anticipated state,compared with high-level basketball players,general collegiate basketball players showed a large knee external rotation angle when they completed the side-cutting action(p=0.048);general collegiate basketball players on the unanticipated state showed larger hip joint abduction angles(p=0.046),knee joint abduction angles(p=0.012),ankle extension angles(p<0.001),and tendency to the heel(p<0.001);high-level basketball players showed larger hip rotation angle(p=0.09),knee abduction angle(p=0.001),ankle stretching angle(p=0.009),ankle adduction angle(p=0.001),and tendency to the heel(p=0.008)on the unanticipated state;higher-level basketball players of general collegiate basketball players on the anticipated state showed larger hips joint external rotation angle(p= 0.001),knee joint abduction angle(p=0.007),ankle joint external rotation angle(p=0.021);higher-level basketball players of general collegiate basketball players on the anticipated state showed large hip abduction angle(p=0.002),hip joint rotation angle(p=0.002),knee joint abduction angle(p=0.004),ankle extension angle(p=0.012),ankle adduction angle(p=0.003).Conclusions:(1)In the unanticipated state,the general collegiate basketball players show greater hip abduction angle,knee abduction angle,tending to use heel contact way.These characteristics may increase the risk of ACL injury.(2)In high-level basketball players show greater hip rotation angle,knee abduction angle and tend to use heel contact in the unanticipated state.These factors are the risk factors of ACL injury.(3)In the anticipated state,college basketball students show a large hip rotation angle and knee abduction angle,which are the reasons for the increased risk of ACL injury.(4)In the unanticipated state,comparedwith the high-level basketball players,the general collegiate basketball players show a large hip abduction angle,hip internal rotation angle and abduction angle of knee joint may also increase the risk of ACL injury.In a word,the general collegiate basketball players are more likely to cause ACL injury in unanticipated state.