Age-related Changes In Neuromuscular Responses And Predictive Cut-off Values For Falls In Middle-aged And Elderly People

Background: With the passage of time,people's age is increasing and their physical function is declining.The most obvious manifestation in daily life is the decline of lower limb muscle capacity.Because of the decline of this ability,the body can not make rapid emergency measures in sudden situations,which triggers a fall.This situation seriously affects people's work,study and rest.Neuromuscular reaction time is an important index of human body.The quality of neuromuscular reaction time directly affects the probability of falling.Research purposes: Through the study of neuromuscular reaction time,this paper observes the changing trend of neuromuscular reaction time with age,proves the correlation between each index of neuromuscular reaction time and physical function,and finally uses ROC curve to analyze the relationship between neuromuscular reaction time and falls,and gives the critical value of falls.Methods: Samples were collected by random sampling in Beijing and Jiaozuo.Ages were between 40 and 87 years old.The data after testing were sorted out and the abnormal values in the samples were removed.The final remaining samples were 243 people,including 66 men and 177 women.A sample of 72 young people aged between 15 and 24 was collected in Changchun.The results of neuromuscular reaction time were divided into pre-reaction time T1(s),post-reaction time T2(s)and total reaction time T1 + T2(s).Three muscles were measured in young people,namely lateral femoral muscle,medial femoral muscle and rectus femoris muscle.By using SPSS25.0 statistical software,the middle-aged and elderly people were divided into two groups,middle-aged group and elderly group.T-test was used to analyze the differences between the age groups of the elderly and between men and women.Origin Pro 9.0 was used to make a scatter plot of the time varying with age.Pearson was used to demonstrate the correlation between neuromuscular response time and physical function.Finally,the ROC curve was used to analyze the predictive effect of each index and fall in neuromuscular reaction time,and the optimal critical value of fall was calculated by Youden index,trigonometric function method and maximum method.The results showed that there was little difference between the lateral femoral muscle,the medial femoral muscle and the rectus femoris muscle.There was no significant difference between the lateral femoral muscle and the medial femoral muscle and the rectus femoris muscle,but there was little difference between the medial femoral muscle and the rectus femoris muscle.In the analysis of middle-aged and elderly people,the difference between male age group is better than that of female.There are obvious differences between male and female,T1 and T1 + T2 of left and right legs.There was no significant difference in T2.The difference between 30 seconds sitting up and 6 meters walking speed is better than 3 meters turning back.Sitting up in 30 seconds and walking speed in 6 meters showed a downward trend with the increase of age,while turning back in 3 meters showed an upward trend with the increase of age.There is no significant difference in the three indicators between men and women.The scatter plot shows that each reaction time increases with age.And the left leg is higher than the right leg,and the female is higher than the male.Each index of neuromuscular reaction time and the area under ROC curve of falls in both left and right legs were larger than 0.5.The final cut-off points were: right leg T1:0.229(s),right leg T2:0.131(s),right leg T1+T2:0.438(s),left leg T1:0.256(s),left leg T2:0.251(s),left leg T1+T2:0.517(s).Conclusion: Among quadriceps femoris,lateral femoral muscle is more suitable for measuring neuromuscular reaction time.Neuromuscular reactions in middle-aged and elderly people are affected by physical function and ability.Neuromuscular reaction time of middle-aged and old people shows the law of aging change,and the reaction time prolongs with the increase of age.Men's neuromuscular reaction time is shorter than women's,and women's neuromuscular reaction time growth rate is faster than men's.The right leg neuromuscular reaction time was greater than 0.131 seconds and the left leg neuromuscular reaction time was greater than 0.251 seconds,suggesting that there was a risk of falling.