| Objective: to reveal the forward and back down the order related biomechanical mechanism of action,from three aspects of kinematics,kinetics and EMG to analyze the forward and back down the order with the interactive relationship between the action and the difference between the sexes,back down the order of relevant research provides empirical evidence,as well as rehabilitation medicine reference or injury prevention.Methods: the biomechanical mechanism research on kinematics and dynamics,by means of EMG synchronization test related biomechanical parameters,the research subjects are 8 male college students(age 23.6 ? 1.4,174.3 ? 6.7 cm tall,weighing70.5 ? 9.5 kg)and 8 female college students(age 24.6 ? 2.4,164.6 ? 6.4 cm tall,weighing 54.7 ? 5.3 kg),with a camera,force plate,EMG and synchronization device and other equipment for forward and back down the order with the synchronous experiment action,processing obtain kinematics and dynamics and EMG data,using SPSS16.0 software for data processing and analysis,statistical methods using single factor analysis of variance,significant level of P<0.05.Results: 1.compared with the positive order under the ground,back down the order with the long period of press,the first peak time and step length is significantly longer;at the moment when the hip angle forward under the order to back down the order is significantly less than the ground,in the center of gravity of the body hip joint and minimum time the angle of the knee joint with significantly less than the positive order back down the order to leave,in the moment of hip joint angle forward under the order with a significantly greater than the back order,the knee angle was significantly less than the positive order back down the order;hip joint angular displacement is significantly less than the ground back under the order a downward order;2.vertical ground reaction force change trend is a Shuangfeng,and the first peak peak value is greater than second,down to the maximum order of vertical ground reaction force is less than the back down the order,and most men are vertical to the ground The reaction is higher than the female;the maximum peak under a positive impulse order than back down the order,and the maximum peak impulse men more than women;with the positive order under the maximum load rate is greater than the back down the order,the maximum load is greater than the rate of male female;under a positive order the 50 ms passive impulse is greater than the back down the order,the male is slightly larger than the female 50 ms in passive impulse.Show 3.characteristics: male rectus femoris EMGmuscle EMG and femoral head two is greater than the positive order back down the order,while the female rectus femoris muscle EMG and femoral head two is positive under the order to back down to less than the order;the tibialis anterior muscle EMG positive order to back down order a gap between men and women is not obvious and there is no significant difference between male and female;gastrocnemius muscle was positive under the order to back down to the order of less than.Conclusion: Compared with the positive ladder,ladder back down because of sight causes need more time to make the body stable,while back down ladder can protect the human knee joint,reduce the ground reaction force of the knee joint damage,and the impact force of men than women under the ladder significantly greater in muscle;job characteristics,positive back down the order and underground limb muscle differences are mainly embodied in the gastrocnemius muscle and tibialis anterior,and the forward and back down the order of lower limb muscle activation sequence is basically the same,the first is the tibialis anterior muscle and rectus femoris muscle activation,and is almost at the same time the gastrocnemius and unit two biceps.The downward step is an abnormal way of activity.It plays a unique role in rehabilitation and injury recovery.However,in practice,we should pay attention to safety and prevent falls. |
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