| Research purposes: this paper based on the Newtonian dynamics equation is constructed the squat exercises every link of human lower limb muscle and joint stress calculation of theoretical model,with every link of body weight load and kinematic parameters for the equation of the boundary conditions using inverse dynamics calculation hip knee ankle joint muscle strength,joint moment and stress distribution,and finally calculate the size of the sole reaction,with load board test results validate the result of the calculation,thoroughly discusses the squat exercises lower limb muscle strength and joint strength,torque characteristics,along with the change of stretch the knee joint Angle change for lower limb special strength training and provide a scientific basis for the diagnosis of sports injury.Methods: the experiment using the kinematics(2D camera,analysis)and dynamic force board(force plate)method,of an athlete USES two kinds of different load(40 kg and 80 kg)of the squat exercises,the squat from low to the upright position throughout the movement process were tested,by using Newton's classical mechanics equation is calculated under dynamic action of each posture indexes of human body joint muscle strength.Research results :(1)the theoretical calculation method for the solution of the torque balance equation is highly consistent with the results of the dynamics test method,which is consistent with the trend of the change of foot pressure of the measured value of the force plate and has no difference in the calculation results(P>,0.05);(2)the calculation results of the three joints of hip knee and ankle in squat training based on the dynamic Newtonian mechanics equation are highly similar to the calculation results under the balance principle,and the dynamic calculation results are far greater than the static calculation results;(3)the index values of the three joints of the hip,knee and ankle all decreased with the increase of the knee extensor Angle;The greater the barbell load,the greater the index value of the three joints of hip,knee and ankle.The results showed that: hip joint torque > knee joint torque > ankle joint torque;hip joint torque > knee joint torque > ankle joint torque;Quadriceps tension > gluteus maximus tension > leg triceps tension;(4)due to the increase of inertia force and coriolis force,the dynamic calculation results of the three joints of the hip,knee and ankle were larger than that of the static calculation results.The stress of the three joints was > of the knee joint,> of the hip joint,and there was a significant difference between the three joints(P<0.05).Research conclusion:(1)based on the principle of balance(static)calculation as a benchmark for checking,the dynamic calculation results with load board measured plantar pressure value as the standard to calibrate the dynamic calculation results,through two calibration results show that the theoretical calculation of the dynamic equation of Newtonian mechanics is adopted to establish the reasonable model and the calculation results are accurate.(2)in the process of squatting training,the personality indexes of the three joints of hip,knee and ankle gradually decrease with the increase of the knee extension Angle,indicating that squatting to the lower position is of great training value;The strength of the three joints of hip knee and ankle increased with the increase of the barbell load,indicating that the barbell load should be considered in the training of weight-bearing squat.The comparison of torque and active muscle tension between the three joints shows that squat training can be used as one of the best exercises to exercise quadriceps.(3)the risk of knee injuries during squat training is higher than that of hip and ankle injuries;In the process of squatting,the patellofemoral joint was subjected to greater pressure at the knee joint,which increased the friction between the patellofemoral bone and the femur.It was proved that weight-bearing squatting could easily cause cartilage wear of the patellofemoral joint. |
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