Comparative Analysis Of Biomechanical Characteristics Of Rapid Squat Under Variable Resisitance And Constant Resistance

Research Objectives: Referring to relevant literature,it is found that there have been some research results on the effect of squatting by changing the conditions and methods.The focus of the domestic scholars research mainly concentrated in different load,different instrument,different level of fatigue and squat of before and after the impact on the size of leg knee joint torque,most research method is to use a specific torque test instrument measuring specific movement under the condition of lower limb knee joint torque size,not together with a specific form of resistance.From the research of foreign scholars,the main research direction is focused on the implementation effect and training effect of different weights and different ways of squatting.On the other hand,it focuses on the training effect of snatch,squat and bench press under different resistance conditions,and less research on squat under different resistance conditions is involved.Condition of different load and different resistance through this study,the subjects quickly squat related indicators of the test data,the analysis of the subjects in different load conditions(30% 1 rm and 40% 1rm),and under the condition of different resistance(constant resistance and variable resistance type 1 and type 2)kinematics and dynamics parameters of lower extremity muscle force difference and characteristics change.In this way,the nature and training function of fast squatting can be more correctly understood,and a theoretical reference can be provided for the subjects to correctly grasp the movement requirements,negative weight and resistance conditions in the practice of fast squatting.Research Methods: In this study,12 male freshman volunteers from the School of Physical Education and Health Science of Zhejiang Normal University were selected by experimental method,and the 1Rm value of squatting with weight of each subject was tested.Then the rapid squat test was started,including constant resistance squats with 30% 1Rm and 40% 1Rm,repeated three times for each weight,and variable resistance squats with 30% 1Rm,repeated three times for each resistance condition.The variable resistance quick squat test was performed using 40%1RM,and each resistance condition was repeated 3 times.One three-dimensional force measuring table(length × width × height: 90×60×10cm)was used to obtain dynamic data,with a sampling frequency of 250 Hz and a sampling time of 4 seconds.Two SONY DCRHC52 E digital cameras were used to obtain Motion images with a shooting frequency of 50 frames/second.The Motion of the subjects was analyzed by the 3D Motion resolution system of Germany SIMI-Motion to obtain the kinematics data.The main research conclusions:(1)under the condition of two different variable resistance quickly squat compared with constant resistance under the condition of rapid squat,participants can more sufficient power to complete the stretching action,time and speed differences reflected different subjects in overcoming resistance situation joints "stuck points" the ability of the differences,the variable resistance type 1 in overcoming the joints "stuck points" on the ability of the more prominent.(2)When fast squatting,no matter what kind of resistance forms of fast squatting,squatting time is shorter than the stretch time,the Angle of the ankle joint changes the largest range,the Angle of the knee joint is smaller than the ankle joint,the Angle of the hip joint changes the least range;In the process of movement,the lower limb joints were the ankle flexor plantaris,the knee joint extensor,and the hip joint extensor.Under the variable resistance condition,the resistance of subjects in the squat stage decreased continuously to the maximum flexion moment,and the resistance was the minimum value in the whole fast squat.The lower limb muscles’ cushioning ability and pushing ability were enhanced,and the centrifugal to centripetal transition was faster,and the pushing speed was the fastest compared with the constant resistance.Variable resistance type 1 is more significant than variable resistance type 2in the above results.(3)in the same load condition,the condition of three different resistance compared to variable resistance type 1 subjects next crouching,least resistance force peak appears the earliest time,the stage of crouch down the smallest percentage of time,the ability to reflect buffering capacity and lower limb muscle stretching strength squats over time(knee buckling moment)biggest strength is minimal.Under the condition of constant resistance,the significant characteristic of the change of the force value is that the peak value of the force is large,accompanied by the rapid decline of the force value.The buffering ability of lower limb muscles plays an important role in muscle contraction during centrifugal contraction.Therefore,strengthening the buffering ability of lower limb muscles and the ability of fast stretching is the key to optimize the training effect of fast squatting.