| Purpose:Sedentary behavior has been listed by the world health organization(WHO)as one of the 10 leading causes of disease and death,and studies have shown that it increases an individual's risk of death.Sedentary behavior increases the risk of diabetes,cardiovascular disease,cancer,mental illness and skeletal muscle disease,and has a negative effect on posture.Understanding the relationship between sedentary behavior and bone density,muscle health and body posture is of great significance for people to establish fitness awareness and carry out targeted physical activities.Foreign studies on sedentary behavior have produced relevant results,but no studies on body posture have been found,and studies on bone density and muscle health have not been conclusive.There are few domestic studies on sedentary behavior.At the same time,there are few studies on the sedentary behavior of college students at home and abroad,and there is a lack of discussion on the sedentary behavior of college students.Therefore,this study measured the bone density,muscle strength,muscle mass,fat content and body posture of college students,and studied the relationship between them and sedentary behavior,so as to enrich domestic studies on sedentary behavior and provide theoretical significance and empirical reference for related studies in the future.Methods:1.60 subjects were recruited,30 male and 30 female.Subjects wore activPAL3~TMM and ActiGraph GT3X+accelerometers to measure sedentary time and physical activity,respectively.The Metrisca bone mineral density instrument was used to measure bone density,the portable muscle strength tester was used to measure muscle strength of lower limbs,the INbody 3.0 body composition analyzer was used to measure muscle mass and fat content,and the PA200LE body posture analysis system was used to measure body posture.2.According to the research object is the average daily sedentary time,the research object is divided into sedentary group(sedentary time?9 hours)and the sedentary group(sedentary time<9 hours).Use independent sample t-test to compare sedentary on bone mineral density between groups with the sedentary group,muscle strength,muscle mass and body posture.3.Partial correlation analysis was used to the research object of activPAL3~TMM measurement on an average day continuous sedentary sedentary time and more than 30minutes,60 minutes of frequency for the independent variable,bone density,muscle strength,muscle mass and body posture as the dependent variable,the average daily MVPA and BMI as control variables,respectively analysis on an average day continuous sedentary sedentary time and more than 30 minutes,60 minutes of frequency and bone density,muscle strength,muscle mass and body posture of the correlation between the indexes.4.Based on the data of the research objects,the interview outline was purposefully prepared,and the focus group interview method was used to have an in-depth understanding of the relevant situations of the research objects,so as to provide a deeper explanation for the research on the relationship between sedentary behavior and body posture.Twelve interview subjects were selected,including 6 in the sedentary group and 6in the non-sedentary group.6 members of each group conducted the interview at the same time and place,and recorded the interview process.After the interview,the interview audio was sorted out and turned into electronic documents.The content analysis method and"three-column"analysis method were used to analyze and extract the interview records to form the interview results.Results:1.The average daily sedentary time of the study subjects was 9.76±1.61h/d.The frequency of continuous sitting for 30-60 minutes per day was 7.49±1.39 times,and the frequency of continuous sitting for more than 60 minutes per day was 3.90±1.05times.,the average bone density of male students(0.33±0.02 g/cm~3 vs 0.31±0.02 g/cm~3,P<0.05)was significantly higher than that of female students.,the muscle mass of boys(58.26±8.23kg vs 39.77±4.66kg,P<0.01),muscle strength of left leg(21.76±5.76kg vs14.47±4.85kg,P<0.01)and muscle strength of right leg(19.21±4.30kg vs 13.72±3.37kg,P<0.01)were significantly higher than that of girls.There was a significant difference between male and female students in head tilt(0.13±3.34 vs 2.23±2.45,P<0.01)and pelvic tilt(-1.03±4.00 vs-2.97±3.06,P<0.05).2.When the subjects were grouped according to the time spent sitting,the number of people in the sedentary group was 38,while that in the non-sedentary group was 21.There were significant differences between the sedentary group and the non-sedentary group in the forward and backward tilt of the head(2.24±1.82 vs 3.48±1.89,P<0.05)and the forward and backward tilt of the trunk(4.00±1.64 vs 4.90±0.44,P<0.05).There was a significant difference between the female sedentary group and the non-sedentary group in head tilt(2.11±1.73 vs 3.73±1.79,P<0.05)and trunk tilt(4.00±1.76 vs 5.00±0.00,P<0.05).There was no significant difference in body posture between the male sedentary group and the non-sedentary group(P>.05).3.The results of partial correlation analysis showed that there was a significant negative correlation between the average daily sitting time of the subjects and the forward and backward tilt of the trunk(r=-0.460,P<0.01).There was a significant negative correlation between the average daily sitting time of girls and the forward and backward torso tilt(r=-0.593,P<0.01).There was a significant negative correlation between the average daily sitting time of male students and the left and right head tilt(r=-0.572,P<0.05).The frequency of continuous sitting for more than 30 minutes per day was positively correlated with muscle mass(r=0.356,P<0.05).There was a significant negative correlation between the frequency of continuous sitting for more than 30 minutes per day and the left-right tilt of lower limbs(r=-0.451,P<0.05).There was a significant negative correlation between the frequency of continuous sitting for more than 60 minutes per day and trunk rotation in girls(r=-0.475,P<0.05).4.According to the results of the interview on body posture,no significant difference was found between the sedentary group and the non-sedentary group,so the overall analysis and discussion were conducted on the responses of all interviewees.In the head posture part,most interviewees often lowered their heads to play with their mobile phones.When they sat at the desk,most interviewees chose to look up to relieve the pressure on their neck.In the lower extremity posture part,when sitting,the interviewees will fold their legs.When standing,they will choose objects to lean against,and constantly switch the center of gravity between their legs.In the exercise mode part,the subjects'exercise was mainly aerobic exercise with various exercise modes.In the subjective part,interviewees will consider maintaining good body posture and have a cognition of good body posture to understand their own body posture deficiency.Conclusion:The overall sedentary time of college students is high.Among the research subjects,64.4%of college students spend more than 9 hours a day sitting on average,and the sedentary time of male students is higher than that of female students.There was no correlation between sedentary behavior and bone mineral density in college students.The frequency of continuous sitting for 30-60 minutes is positively correlated with muscle strength,while the frequency of continuous sitting for more than 60minutes has nothing to do with muscle strength,suggesting that the duration of continuous sitting may have different effects on muscle strength.There is a negative correlation between the sedentary behavior and the body posture of college students,which may be due to the fact that most of the sedentary behavior of college students occurs when they are lying down,and they often adjust their body posture in the sitting position,and the body posture of sitting position is more standard than that of standing position. |
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