Effect Of Marathon Running On In-vivo 6DOF Kinematics Of Tibiofemoral Joint

Objective:Knee injuries often occur during or shortly after marathon running,and are linked to knee kinematic changes.The kinematics of healthy knees during pre-and postmarathon running have not been examined with high-speed dual-plane fluoroscopic imaging system(DFIS).This study aimed:(1)To evaluate the effects of marathon running on in-vivo six-degrees-of-freedom(6DOF)knee kinematics during walking and running by using a combined high-speed DFIS and magnetic resonance imaging(MRI)technique.(2)To analyze and compare instantaneous 6DOF knee kinematics before,at,and after heel strike during walking and running using a combined highspeed DFIS and MRI technique.Methods:Ten healthy recreational runners underwent knee MRI within 24 h before marathon running to construct three-dimensional(3D)knee models.Participants walked and ran on a treadmill while fluoroscopic images were acquired at 200 Hz;3D knee bone models were then related to the fluoroscopic images to capture the 3D motion of the joint within 24 h before and within 6h after marathon running.3D knee bone models were then related to the fluoroscopic images to capture the 3D motion of the joint.Instantaneous knee kinematic characteristics were calculated at three time points: 0.05 s before heel strike,at 0.00 s relative to impact(heel strike),and 0.05 s after heel strike.All pre-and post-marathon measurements were compared.To analyze and compare instantaneous 6DOF knee kinematics before,at,and after heel strike during walking and running Results:1.During post-marathon walking,posterior femoral translation was increased by1.4 mm at initial contact(p = 0.015);proximal-distal distance decreased by 0.7 mm and0.8 mm,at initial contact and after contact respectively(p = 0.039,p = 0.046);and valgus femoral rotation increased by 1.2° after contact(p = 0.027).During postmarathon running,proximal-distal distance was decreased by 0.7 mm and 1.0 mm at initial contact and after contact(p = 0.011,p = 0.003)respectively;knee flexion was decreased by 4.3° before contact(p = 0.007);knee flexion was increased by 1.8° and2.6° at initial contact and after contact,respectively(p = 0.038,p = 0.011);external femoral rotation was increased by 1.2° and 1.8° at initial contact and after contact,respectively(p = 0.012,p = 0.037).Valgus femoral rotation after contact was increased by 2.3°(p =0.001).2.During walking,knee extension angle and internal femoral rotation at heel strike were increased by 8.49° and 7.27° relative to 0.05 s before heel strike,respectively(both p < 0.001),proximal-distal distance at 0.05 s before heel strike was increased greater than at heel strike(p = 0.024)and increased greater than at 0.05 s after heel strike(p = 0.022),and the flexion and external femoral angles at heel strike were increased by 7.22° and 6.53° relative to at 0.05 s after heel strike(both p < 0.001).During running,the flexion angle and proximal-distal distance at heel strike were decreased by 10.51°(p < 0.001)and 1.42 mm(p = 0.002),respectively,compared to0.05 s before heel strike but similar to the data obtained at 0.05 s after heel strike(p =0.008 and p = 0.013,respectively),and the flexion angle was increased by 3.72° at 0.05 s after heel strike compared to heel strike(p = 0.047).3.At 0.05 s before heel strike,flexion(p < 0.001),external femoral rotation(p =0.032),and the proximal-distal distance(p = 0.005)were greater during running than walking.At heel strike,extension-flexion direction(p < 0.001),external-internal femoral rotation direction(p < 0.001),posterior-anterior femoral translation direction(p = 0.034),and proximal-distal distance(p = 0.040)differed significantly between running and walking.At 0.05 s after heel strike,flexion(p < 0.001),external femoral rotation(p = 0.011),and proximal-distal distance(p = 0.015)were greater during running than during walking.Conclusion:1.The change of 6-DOF movement of tibiofemoral joint after marathon may potentially increase the risk of knee injury.This study provides runners and coaches with important information about the tibiofemoral joint movement after marathon running,which can be used to guide the recovery and training of runners.2.To understand the 6DOF movement characteristics of tibiofemoral joint in healthy people during walking and running,which lays a very important foundation for people to fully understand the normal movement of knee joint and correct abnormal movement.