The Risk Of ACL Injury In College Basketball Players During Stop-Jump Under Different Run-Up Speeds

Objective: The purpose of this study was to discuss the influence of different run-up speeds on the risk factors of ACL injury during the sudden stop jump shot,to prevent competition like project scram jumps high incidence of knee joint in the non-contact ACL injury,formulate scientific and reasonable special physical training plan,promote the development of basketball movement and scientific guiding the national fitness has important guiding meaning and theoretical reference value.Methods: This study mainly adopts an experimental method and selects 15 second-level basketball players from the Wuhan University of Sport who meet the inclusion criteria as the research objects.Vicon 3D Optical Motion Capture System and Kistler 3D force measuring table,Noraxon Wireless Surface EMG testing System synchronous acquisition subjects in slow approach（3 m/s±5%）and rapid run-up（4 m/s±5%）stop takeoff and landing period under the knee joint angle in all directions,the peak torque,the ground reaction force and the corresponding time,major muscles around the knee joint root-mean-square amplitude and integral electrical values and biomechanical indexes such as muscle contribution.The collected data were sorted out by Excel and analyzed by paired sample T-test with SPSS26.0statistical software.All indicators showed statistically significant differences at P < 0.05,and P < 0.01 was very significant.Results: Kinematics:（1）Compared with the slow approach,the knee flexion Angle of the fast approach was significantly smaller than that of the slow approach at the peak of VGRF,and the difference was significant（P=0.000）.（2）The Angle of knee abduction was significantly different at different run-up speeds（P < 0.05）,and the Angle of knee abduction was larger in fast run-up than in slow run-up.（3）There was no significant difference in the Angle of internal and external rotation of knee joints between slow and fast run-up（P > 0.05）.Dynamics:（1）The peak value of vertical ground reaction force,peak time and load rate of sudden stop jump shot of basketball players at different run-up speeds have very significant differences（P < 0.01）.（2）The peak value of backward horizontal ground reaction force and load rate were significantly different（P < 0.01）,while the peak time was significantly different（P < 0.05）.（3）There is a significant difference between the knee extension moment of basketball players at the fast approach speed and the knee extension moment of basketball players at the slow approach speed.（P < 0.01,P=0.000）,the knee buckling moment was different,but there was no statistical significance（P > 0.05）.（4）The external rotation moment of knee joint during fast run-up was significantly higher than that during slow run-up（P <0.05）,while there were no significant differences in adduction,abduction and internal rotation moment of knee joint at different run-up speeds（P > 0.05）.Electrophysiology:（1）The RMS amplitude of the medial head of gastrocnemius muscle,biceps femoris muscle,semitendinosus muscle,rectus femoris muscle;and vastus lateralis muscle increased significantly under fast approach（P < 0.05）,while the RMS amplitude of tibialis anterior muscle,lateral head of gastrocnemius muscle and vastus medialis muscle showed an increasing trend under fast approach,but showed no significant difference（P > 0.05）.（2）Half a tendon muscle electromyography and vastus lateralis integral values is very significant difference（P < 0.01,P = 0.000）,rectus integral electrical values under the rapid run-up significantly increased（P < 0.05）,while the pretibial muscle,medial head of the gastrocnemius muscle,the lateral head of the gastrocnemius,biceps and shares the inside of the muscle under the rapid run-up speed integral electrical values has increasing trend,But there was no significant difference（P > 0.05）.（3）The contribution rate of tibialis anterior muscle and vastus medialis muscle was significantly decreased under fast approach（P < 0.05）,but there was no statistical significance in the lateral head of gastrocnemius muscle,biceps femoris muscle,semitendinosus muscle,gastrocnemius medial head,rectus femoris muscle and vastus lateralis muscle（P > 0.05）.Conclusion:1.The run-up speed has a significant influence on the sudden stopjump shot of basketball players.The faster the run-up speed is,the greater the ground reaction force,joint load and knee extension torque,and the greater the anterior tibial shear force,and the more likely ACL injury occurs.2.The knee flexion Angle is significantly smaller and the knee abduction Angle is significantly increased when the basketball players stop-jump shot with fast run-up.3.When the run-up speed is stable,the muscle activation degree of VL,VM and RF is significantly higher than that of BF and SEM.The excessive muscle force ratio of active and antagonistic muscles of knee joint increases the instability of knee joint,which may be the main cause of ACL and knee cartilage injury.