Effects Of Fatigue On Tripping Biomechanics

China has entered the aging society gradually,aging population is becoming a serious problem.Tripping is one of the leading cause of accidental or unintentional injury deaths.Besides,tripping is the main causes of the occupational accidents in the workplace.With quick life rhythm of modern people,fatigue affects people's daily life.People are often in a state of fatigue,such as muscle fatigue and mental fatigue,which has a great impact on people's lives and may cause economic loss and major casualties.The purpose of this paper is to collect data on normal gait and tripping of subjects under lower extremity muscle fatigue and mental fatigue,and analyze and discuss the effect of fatigue on tripping in depth.In this study,the subjects were recruited in the vicinity of the Shenzhen University and the surrounding community randomly.A total of ninety six young healthy adults.The subjects were randomly divided into three groups: the no fatigue group,the lower extremity muscle fatigue group and the mental fatigue group.There was no statistical difference in the height,age and body weight of each group.In this study,we induced lower extremity muscle fatigue by having subjects perform a repeated sit-to-stand task,and induced mental fatigue by having subjects in the experimental condition work on the AX-test for ninety minutes.In this study,the effects of lower extremity muscle fatigue and mental fatigue on the normal gait and tripping of the subjects were studied by controlled experiments.The kinematics data during the normal gait and tripping experiments were measured by VICON motion capture system.By analyzing experiment data,we can draw some conclusions as follow:(1)The fatigue related decrease in muscle strength did not have a significant impact on the normal gait and tripping data of the subjects.(2)Although mental fatigue limits physical movement in subjects through higher perception of effort,it does not have a significant impact on normal gait.(3)The time of reaching the maximum trunk angular velocity in mental fatigue group was significant greater than that in no fatigue group,and the trunk angle at the time of recover limb loading in mental fatigue group was significant smaller than that in no fatigue group.Mental fatigue will increase reaction time and delayed response execution.Therefore,recovery response after a trip could be delayed by mental fatigue.Indicating that mental fatigue limits the performance of recovery response after a trip in subjects of mental fatigue group through higher perception of effort and delayed response execution.The mental fatigue related increase reaction time,higher perception of effort and delayed response execution may impact the margin of stability and the boundary of the base of support and restore the balance failure.We found that mental fatigue is a risk factor for trip and falls.Thus,exposures to mental fatigue should be avoided in order to reduce the risk of tripping.