Introduction: Many studies have explored the effects of kinematic and kinetic factors on the high incidence of anterior cruciate ligament injuries among athletes. However, the variation in the center of pressure direction during running and standing on single leg in athletes who have or have not undergone ACL surgery using a force plate treadmill has received little attention.The aim of this study is to examine the changes in the center of pressure direction in the running cycle and standing single leg of athletes with and without a history of ACL surgery using an instrumented treadmill and a Vicon 8-camera 3-dimensional motion analysis system and the possibility of their re-injury.
Research Methodology:15healthy athletes and 15athletes with a history of ACL surgery in the last 5-8 months participated in the study.in dynamic state Initially, the treadmill (Zebris Medical GmbH,Germany) was calibrated with zero degree slope and then they started running at the desired speed (9 km/h for 1 minute).The data analysis was performed by SPSS version 26. Independent t-tests were used to examine possible between group differences at the significance level of 95% (P≤0.05). in static state,Kinematic and kinetic data were collected using a Vicon 8-camera 3-dimensional motion analysis system at 200 Hz, synchronized with a Kistler force platform sampling at 1000 Hz.Marker trajectories were processed using Nexus software, and Visual 3D and MATLAB software were employed for variable calculation and analysis. The Shapiro-Wilk test assessed data normality, and the independent t-test evaluated significant differences between groups. Marker trajectories were processed using Nexus software, and Visual 3D and MATLAB software were employed for variable calculation and analysis.
result: Results in dynamic state showed that the mean and SD values in the healthy group were 2.26 ± 0.03 and in the ACLR group were 2.13 ± 0.30, and the statistical value of T was 0.99 and the statistical value of p was 0.33 (p>0.05). Therefore, there was no significant difference in the center of pressure direction of the running cycle between athletes with and without a history of ACL injury in 5-8 months after surgery. in static state, peak ground reaction force (vGRF) and rate of loading (ROL) at IC significantly increased in the ACLR group compared to the healthy group (P=0.002, P=0.001).
conclusion:we can conclude that changing in the direction of the center of pressure cannot be a good measure to predict and prevent the possibility of ACL re-injury.The elevated vGRF, indicating a stiff system during skill performance and a heightened risk of ACL re-rupture. Therefore, athletes should receive feedback from sports coaches to control and adjust ROL while enhancing overall sports performance.