Comparative Study On Four Calculation Methods Of ACL Load Evaluation During Landing

Background In sports,the non-contact anterior cruciate ligament(ACL)is a high incidence of knee injury type,common in lower limb impact landing,change,twist and other actions.Unlike in vitro studies,the in vivo load of ACLs can only be estimated by dynamic medical imaging techniques(such as Fluoroscopy)or musculoskeletal mechanics,which has a higher reliability,but the latter has better applicability,And is currently the mainstream method used in the study of ACL load assessment in the course of exercise.However,it can be found that there are differences between the different research methods for the calculation of ACL load assessment in motion,and it has not yet formed a consensus standard,and the experimental conditions,objects and actions observed in different studies are different.Different results are difficult to compare or verify with each other.Purpose The method of calculating the load of the more common ACLs in the literature was studied.Under the same original data condition,the difference of the results caused by the different methods was investigated and the biomechanical mechanism was discussed.The results of this study will provide data support for the qualitative comparison of different calculation results,help to deepen the understanding of the damage mechanism of ACL,but also for the future development of more in vivo load assessment methods to help.MethodsSelect 12 female player(Age:(20.1 ± 0.9)yr;height:(170.5 ± 5.9)cm;body weight:(57.4 ± 5.6)kg).through the three-dimensional infrared camera capture system(VICON,200Hz)(Kelsler,1000Hz)and surface electromyogram acquisition system(Delsys,4000Hz)were used to collect the kinematics,dynamics and surface electromyography data of the lower limbs during the 40 cm high-rise landing.The data were analyzed by Visual 3D motion analysis software.One representative participant data was selected(the vertical ground reaction curve and the corresponding mean curve were the highest),and four different calculation methods were used to evaluate the ACL load in the landing action.(2)Based on the mechanical model and method of Paul Devita,the main muscle tension was separated,and the femur and tibia were calculated.(2)Based on the mechanical model and method of Paul Devita,the main muscle tension was calculated,and the tibial tangential component(ATSF1)(ATSF2);(3)to abandon the method of separation of muscle tension in the method,and the use of OpenSim CMC to optimize the muscles around the knee muscles,to recalculate the tangential component of the intercourse force(ATSF3);(4)using the OpenSim ACL model provided by Jilia kar,using only the OpenSim correlation process to estimate the ACL pull(FACL)Results(1)The peak values of ATSF1,ATSF2,ATSF3 and FACL are 1.1BW,2.0BW4.5BW and 1.7BW respectively.The peak time is 50%,80%,55% and 35% of the landing period,respectively.(2)Based on the joint torque contribution and muscle physiological cross-sectional area method femoral quadriceps,posterior femoral muscle and gastrocnemius muscle strength were estimated to be 17 BW,7.5BW and 1.7BW,respectively,Based on the OpenSim CMC dynamic optimization method,Muscle strength,femoral muscle and gastrocnemius muscle strength were 7.5BW,2BW,2.4BW.(3)Using the OpenSim dynamic optimization,the EMG signal of medial muscle,rectus femoris,femoral biceps and gastrocnemius muscle in the process of landing was compared with that of EMG signal High consistency.Conclusion Based on the inverse kinetic calculation method,it can not quantify the contribution of muscle force to the ACL load and underestimate the ACL load.Based on the difference between the mechanical model and the OpenSim CMC calculation results,the difference between the muscle force and the peak time is different.Knee joint shear force may overestimate ACL force.