Biomechanic of balancing and adjusting the human body in backward slip

Effect of multiple balance interference on adjustment of slipping from moment of sitting to standing and walking was analyzed from perspective of sports biomechanics, impact of external interference and fatigue sliding state on human balance was examined. When subjects complete sit-up and normal forwardwalking, dynamic slides were used to make a sudden forward slide. This is to effect a falling trend backward. Noraxon surface electromyography test system, Kistler three-dimensional force plate, BTS three-dimensional infrared motion capture system, and Ariel video analysis system were used to record simultaneously kinematics, dynamics and EMG parameters during normal sitting and backward slipping. Biodex multi-jointisokinetic force test system was used to achieve fatigue of lower limb joint muscle. Sitting up, effective adjustment of center of gravity, adequate support for lower limbs and corresponding adjustment of upper limb joints are all key factors to avoid slipping backwards. When slipping backwards, people usually step out are covery pace. improve hip height, accelerate rate of hip rise and increase angle of shoulder twist to keep balance. From sitting to standing and walking, value of ground reaction force and pressure center movement range increase significantly compared to normal state, people needs more force and move longer distance to make themselves balanced. During sudden sliding and fatigue after slip, significant changes in force and sway in left-right directions lead to greater risks of falling. In fatigue state, the ability to adjust balance decreases. Surface electromyography (sEMG) can be used to measure muscle activation. From sitting to standing, sudden sliding leads to significant increases in integrated electromyography in medial, femoral, tibial, and rectusfemoris. These changes indicate that the body needs to mobilize more sports units to prevent falling.