Analysis Of The Biomechanical Characteristics Of The Lower Limbs During The Rising Phase Of Self-Weighted Squats In Sedentary Male College Students In Different Positions

Objectives: To explore the biological characteristics of self-weight squats in sedentary male college students in different positions,in order to provide an experimental basis for preventing lower limb sports injuries and choosing the correct squats training positions in sedentary male college students.Methods: Recruiting 60 sedentary male college students as an experimental group,the kinematics,dynamics,and surface electromyography signals of eight self-weight squat positions((1)1.0 times shoulder width-toe neutral-trunk forward,(2)1.0 times shoulder width-toe neutral-trunk upright,(3)1.0 times shoulder width-toe external rotation30°-trunk forward,(4)1.0 times shoulder width-toe external rotation 30°-trunk upright,(5)1.4 times shoulder width-toe neutral-trunk forward,(6)1.4 times shoulder width-toe neutral-trunk upright,(7)1.4 times shoulder width-toe external rotation 30°-trunk forward,(8)1.4 times shoulder width-toe external rotation 30°-trunk upright)with different foot spacing(1.0 times shoulder width,1.4 times shoulder width),toe position(toe neutral,toe external rotation 30 °),and trunk position(trunk forward,trunk upright)were collected in random order using a three-dimensional dynamometer,a three-dimensional motion capture system and a surface electromyography system indicator,A one-way ANOVA was used to compare the differences in biomechanical indices during the upward stage of the self-weighted squats between the different positions.Result:(1)There were significant differences in the right hip extension torque,hip abduction torque,hip internal rotation torque,knee extension torque,knee adduction torque,knee external rotation torque,ankle plantar flexion torque,ankle abduction torque and ankle internal rotation torque in the eight combined positions(P<0.05).(2)There were no significant differences in the X-axis,Y-axis and Z-axis of the vertical ground reaction force on the right of the self-weight squat in the eight combined positions(P>0.05),and there was no significant significance.(3)There were significant differences in the right hip flexion angle,hip abduction angle,hip internal rotation angle,knee flexion angle,knee adduction angle,knee external rotation angle,ankle dorsiflexion angle,ankle varus angle,and ankle internal rotation angle in the eight combined positions(P<0.05).(4)There were significant differences in the right hip flexion ROM,hip abduction ROM,hip internal rotation ROM,knee flexion ROM,knee adduction ROM,knee external rotation ROM,ankle dorsiflexion ROM,ankle varus ROM(P<0.05),and no significant difference in ankle internal rotation ROM(P>0.05)in the eight combined positions.(5)There were significant differences in the standardized integrated EMG of the right rectus femoris,biceps femoris,semitendinosus and medial gastrocnemius(P < 0.05),but no significant differences in the standardized integrated EMG of the gluteus maximus,gluteus medius,vastus lateralis and vastus medius(P > 0.05),indicating no statistical significance.(6)There were significant differences in the standardized RMS of the right gluteus medius,rectus femoris,vastus medius and biceps femoris(P < 0.05),while there were no significant differences in the standardized RMS of the gluteus maximus,semitendinosus,vastus laterals and medial gastrocnemius in the self-weight squat in the eight combination postures(P > 0.05).(7)The highest contribution of the right lower limb muscles in the eight combined positions of the self-weight squat were gluteus maximus,rectus femoris,medial gastrocnemius,gluteus maximus,medial gastrocnemius,rectus femoris,medial gastrocnemius and rectus femoris.(8)Under the eight combined postures,the muscles of the right lower limb of the self-weight squat start from the medial gastrocnemius and gluteus maximus,the vastus laterals was the latest.Conclusion:(1)When using eight combined postures for squatting with self-weight,under the condition of 1.4 times shoulder width foot distance,it can relieve hip,knee and ankle extension and external rotation pressure,promote hip and knee abduction activities,and have a good training effect on gluteal muscle group,rectus femoris and posterior calf muscle group.(2)When using eight combined postures for squatting with self-weight,under the condition of toe external rotation 30°,it can reduce the internal rotation pressure of the hip and ankle joints,promote hip flexion and abduction,knee adduction and external rotation angle and ROM,and have a good training effect on the posterior calf muscle group.(3)When using eight combined postures for squatting with self-weight,under the condition of forward trunk flexion,the pressure of the knee joint decreases,and the hip flexion angle and ROM are significantly increased,which is strongly stimulating for the posterior femoral muscle group.(4)When using eight combined postures for squatting with self-weight,the medial gastrocnemius,gluteus maximus,semitendinosus and gluteus medius contributed earlier,while the vastus laterals and biceps femoris contributed relatively later.The contribution of the gluteus maximus was highest in position(1)and position(4),the contribution of the rectus femoris was highest in position(2),position(6)and position(8)self-weight squat,and the contribution of the medial gastrocnemius was the highest in position(3),position(5)and position(7)self-weight squat.