Characteristics And Gender Differences In Muscular Athletic Capability In Elbow And Knee Joints Of Aged People

Objective: To explore the characteristics of age-related changes of muscle strength in elbow and knee joints among middle-aged and elderly adults in China aged 46 to 65 years,including the age-related changes of maximum muscle strength,muscle explosive force and muscle endurance between men and women.The research could provide the basis for data collection and statistics of muscle movement ability of middle-aged and elderly people in China.Methods: A total of 246 middle-aged volunteers including 120 males and 126 females were selected to measure the muscle strength and body shape aged 46 to 65 years old.All tests are basis on complete voluntariness of all subjects.The muscle strength and muscle explosive force were tested of the male volunteers and female volunteers respectively.The tested muscle groups including elbow joints and knee joints on left and right side,respectively,by means of self-developed digital isometric muscle function test system.Body shape(Weight,lean body mass,upper arm and thigh girth)were also tested.We analyzed the muscle strength data of each age group and analyzed the correlation between muscle strength and body shape index of each age group.Three key indexes of maximum muscle strength,explosive force,muscle endurance were tested respectively.Meanwhile the body shape indicators(including weight,lean body weight,upper arm circumference and thigh circumference)were collected.The descriptive statistics,the trend analysis,the correlation analysis with correlation network analysis,One-way ANOVA test and PCA visualization analysis were employed to distinguish the gender differences and the ageing-related variations.Results:(1)the descriptive statistics results showed the lower differences of body shape indexes,but higher differences of high jump to touch(JUT)and standing long jump(SLJ)between the minimum age group and maximum age group;the decreases with age on muscle strength with obvious differences between left and right sides in Male,as well as the large change on the knee extensor muscles on the left side;The relative biggest change in muscle strength occurred in knee joints with age 45~49 but in elbow joints with age 50~54;the relative higher explosive force showed in knee joint extensor on the left side,and the explosive force curve showed the significant inflection point at 100 ms as well as the higher values after age of 55;the decreased variations with age showed the maximum muscle explosive force with highest value in age of 50~54;the muscle endurance showed the relative higher values in knee joint and extensor muscle,as well as the obvious differences of muscle fatigue index between left side and right side especially in Female,but the significant changes in age of 60 for both male and female.(2)the trend results showed the relative higher values of muscle strength in male and the first decline and then rise characteristics with the increase of age,and the slightly ahead of age on the right side compared with that on the left side at the age of 55 on muscle strength;the obviously decline showed in muscle explosive force variables with the age increasing especially for male;the knee joint showed relative huge fluctuations especially at age of 53;muscle endurance showed higher changes in knee joint and the decreased trend with age especially at age of 55 for female and at age of 57 for male.(3)the correlation analysis and its network results showed the highest significant difference among explosive force variables(p<0.001);the explosive force variables showed the significant correlations among each other(p<0.001)but muscle fatigue index showed differences in both left and right side as well as in different muscle groups;the relative network showed the relative significant correlations with muscle strength and explosive force variables in flexor groups in the right side,but significant in extensor groups in the left side.(4)the results of One-way ANOVA indicated the higher numbers of difference between age groups in female,as well as in extensor groups,and the significant differences occurred at the comparison between the minimum and maximum age groups,however the almost completely opposite results happened in male with few not significant difference numbers(p<0.1).(5)the results of PCA showed the main influences factor of bilateral muscle groups in male and female groups were related with explosive force variables(mainly including MEF200,MEF250 and MEFmax),which were also the main explanation factors.The influence factors to elbow joint flexor and knee joint muscle were also consisted of muscle fatigue index.Conclusion: The both muscle group differences and gender differences occurred in age related changes of elbow and knee muscles in middle aged and elderly people,as well as the difference between left side and right side,and the variations in different age intervals.The related variables showed decrease trend with age increasing showing the obvious changes at age of 55.The strong correlation occurred in strength variables and displayed significant differences in both left and right side as well as in different muscle groups.The relative higher correlation between muscle strength variable and explosive force variables in flexor muscles on the right side,while both flexor and extensor muscles on the left side.The relative higher numbers of difference between age intervals occurred in female,as well as in extensor muscles.The age of 50 and 55 became the key elements for female knee extensor muscles,while muscle explosive forces at 200 ms ad 250 ms and the maximum value became the most primary influencing factors as well as the primary explanation factors.