Effects Of Different Knee Pads On Kinematic Characteristics Of Knee Joint Under Downhill Condition

Objective: To analyze the biomechanical effects of different types of knee pads on lower extremity knee joint motion.In this study,the kinematic characteristics of knee joint were measured when the knee joint was not used or used with different knee protection at different slopes.Methods: Twelve healthy male subjects(21.5±3.5years,height:174.5±5.0cm,weight: 73.5±5.5kg)were enrolled in the study.The subjects were aware of the process and had no injuries to the joints of the lower extremities six months before the experiment.The evaluation of lower extremity measurement should be normal.A six-degree-of-freedom platform(diameter 2m)is used as a motion simulation platform,and three slopes are set up: 0°,-7°,-14°.Subjects walked at different angles of slopes.The kinematics characteristics of knee joint were calculated by using Vicon three-dimensional motion capture system to collect the three-dimensional coordinate data of space-time parameters and lower extremity related markers,and the frequency was set to 200 Hz.Results: With the increase of downhill slope,the step size increased.Both the open-hole knee pads(No.1::0°51.00±2.53;-7°48.96±4.03;-14°58.38±4.12)and the cladding knee pads(No.2:0°52.42±2.19;-7°56.35±3.65;-14°61.58±2.95)could effectively reduce the range of motion of the knee joint than wearing no knee pads(0°63.85±2.99;-7°57.87±2.76;-14°65.76±4.4).The performance of No.2 knee berth was more obvious.Conclusion: The step will grow with the gradient.There was no significant effect on the space-time parameters whether the subjects wearing the knee pad or not.Both open-hole knee protection and cladding knee protection can effectively reduce the peak flexion angle and joint motion of human knee joint at different slopes.The performance of the open-hole knee pads(No.1)was more obvious and stable,which also showed that the knee pads can play a certain fixed effect on the knee joint under the above three kinds of slope,and accordingly reduce the excess movement of the knee joint so that can avoid harm.However,wearing a cladding knee pads on a downhill slope with a larger tilt angle had a slightly less effective fixation effect on the knee joint.