| Research purpose: Running is a very popular form of physical activity.More and more novice runners participate in running activities.Because novice runners do not have a clear understanding of running injuries and the basis of running is weak,resulting in a high rate of lower limb joint injuries.The lower limb joint injury is mainly caused by the repeated impact of running load on the lower limb joint,and the running speed is an important reason that affects the changes of the lower limb joint force and joint load.At present,the variation characteristics of different running speeds affecting the work of the knee and ankle joints of the lower limbs,the load of a single gait cycle and the cumulative load per unit distance are not clear.Therefore,this study analyzes the kinematics,dynamics of the lower limb knee and ankle joints with different running speeds,and the characteristics of the joint cumulative load changes per unit distance,which provides a theoretical basis for popular scientific running.Research Method: Twelve ordinary male male college students from Beijing Sport University were selected as the research object.The VICON infrared high-speed motion capture system and the Berfec Fit three-dimensional force measuring platform were used to simultaneously collect the kinematics and dynamic parameters of the subjects at the stable stage of 8km / h,10 km / h,12 km / h and 14 mk / h speed running.Use Nexus 2.6 software to collect and export raw data files of lower limb kinematics and dynamics,process raw data through Visual 3D software and obtain spatiotemporal parameters of lower limb gait cycle,joint angle,joint torque and joint power of knee and ankle joints,etc.parameter.Use Microsoft Excel 2016 to calculate the spatiotemporal parameters such as gait cycle,stride,and cadence of four speeds,the angle parameters of the flexion and extension joints of the knee and ankle joints,and the peak torque,joint power,joint work and cumulative load of the flexion and extension joint Kinetic index parameters.The SPSS 20.0 software was used to perform single-factor repeated measurement variance analysis on the parameters of knee and ankle joints with different running speeds,and the statistical significance level was defined as p<0.05.Research results: 1.Lower limb kinematics test results at different running speeds:Comparison of four running speeds.With the increase of speed,the gait cycle(P <0.01)becomes shorter,the ground contact time(P <0.01)becomes shorter,and the stride length(P <0.01)increases,the step frequency(P <0.01)increases.With the change of speed,the knee flexion angle and ankle flexion-extension angle did not change significantly during the support phase.2.Results of lower limb dynamics test at different running speeds: During the ground contact phase,the knee extension torque,peak power,and knee work did not change significantly with speed;the ankle joint plantar flexion peak torque increased significantly with speed(P <0.01),the peak power of the ankle joint during the cushioning and grounding extensions of the ankle joint increased significantly with the increase of speed(P <0.01),and the work of the ankle joint increased significantly with the increase of speed(P <0.05).3.Result of lower limb joint load test at different running speeds: At four running speeds,the periodic load of knee joint gait and the periodic load of ankle joint gait did not change significantly with speed(P> 0.05);Cumulative load decreases significantly with increasing speed(P <0.01).Conclusion:1.The running speed increases from 8km / h to 14 km / h,and it will not affect the knee flexion angle,ankle dorsiflexion and plantar flexion angle,knee peak torque,peak power and joint extension Work,but it will increase the peak torque,peak power of the ankle joint plantar flexion and the work of the ankle joint.2.The running speed increases from 8km / h to 14 km / h.The cumulative load of the knee and ankle joints of the runner per unit distance decreases,but there is no significant change in the load of a single gait cycle. |
