Simulation Comparison Of Two Plyometrics Training Movements Of Lower Limbs Based On OpenSim

Research purposes: Lower limb isometric training is one of the most commonly used training methods for lower limb explosive force,while leapfrog and deep jump exercises are the two traditional training methods in lower limb isometric training.In this paper,OpenSim computer simulation is used to calculate and analyze the biomechanics related indexes of the human lower limbs during the completion of two training actions,and to explore the changes in the characteristics of human lower limb kinematics,dynamics and muscle mechanics in a single action cycle of two different training methods,and find out the difference between the two different training methods,the comparison of the actual effects of the two plyometrics training methods on the improvement of lower limb strength,provides a scientific basis for the specific strength training of the lower limbs of each sport.Research method: Collect the kinematics and dynamics data of 12 professional athletes in track and field for deep jump and frog jump.The kinematics data is collected by the Vicon infrared high-speed photography system with 9 cameras,the frequency is200 Hz.The dynamic data uses two Kistler force plates to simultaneously collect the ground reaction force,the collection frequency is 1000 Hz,and the threshold is 5-10 N.Use Notepad++ text editor software to edit the human body jumping motion model,and use the static optimization method in the human body motion simulation software OpenSim4.0 to calculate the muscle strength changes of the lower limbs during the super isometric contraction of the joints of the lower limbs during the support phase of the deep jumping motion and the frog jumping motion.,And calculate muscle contraction length,rate and muscle strength.Research result: The force plate shows that the support of the deep jump action in one action cycle is less than that of the frog jump action,and there is a significant difference;the ground reaction force generated by the deep jump action is greater than the ground reaction force of the frog jump action.The angle of hip,knee,and ankle joint angle changes caused by deep jumping are smaller than those of frog jumping,and there are significant differences;the hip joint torque of the deep jump action was significantly greater than that of the frog jump action,and the two movements produced a small difference in the moments of the knee and ankle joints.Both the deep jump action were greater than the frog jump action,but there was no significant difference;The jumping support phase of the two movements(the two phases of buffering and pushing and stretching)the exercise effect of the ankle plantar flexor(calf triceps)is better than the deep jump,the exercise effect of knee extensor(quadriceps)is better than leapfrog.the exercise effect of the hip extensors(gluteus maximus)is different in the buffering stage and the thrusting stage,that is,in the buffering stage,the leapfrog is better than the deep jump,and the depth of the jump is better than the leapfrog in the thrusting stage;The exercise effect of the hip extensors(gluteus maximus)is different in the buffering stage and the thrusting stage,that is,in the buffering stage,the leapfrog is better than the deep jump,and the depth of the jump is better than the leapfrog in the thrusting stage;The contraction amplitude of the extensor muscles of the hip,knee and ankle 3 joints changed for the leapfrog action to be greater than the deep jump action.Research conclusions: The stepping time(support phase)of the deep-jumping action is shorter than that of the leapfrogging action,and the angle change of the lower limb 3 joints and the change of the center of gravity of the deep-jumping action are smaller than that of the leapfrogging action.Compared with the leapfrog movement,the deep-jumping action produces greater ground reaction force,and the joint torque of the 3 joints of the lower limbs in the deep-jumping action is greater than that of the leapfrogging action.In terms of muscle training effects,the two types of lower limb muscles contribute the most to the improvement of calf triceps muscle strength in the supporting phase of jumping action;Leapfrogging is better than deep jumping during the supporting phase of the ankle plantar flexor muscles and the buffering phase of the hip extensor.The deep jumping exercise is better than the leapfrogging during the supporting phase of the knee muscles and the thrusting phase of the hip extensors.