| Objectives:To compare the effects of aerobic exercise interventions of different intensities on cardiorespiratory endurance,lower limb strength and mental health in sedentary university students under the premise of controlling the total amount of exercise,and to provide a basis for scientific and personalised exercise prescriptions for healthy people.Methods:Thirty-five healthy university students were included according to inclusion and exclusion criteria.General demographic information was collected on the subjects,including gender,age,height,weight,resting heart rate and blood pressure,sedentary time,and time spent in daily activities.The subjects were randomly divided into a control group(Control,CTL)(n=10),a high-intensity interval training(HIIT)group(n=11)and a moderate-intensity continuous training(MICT)(n=14),with the MICT group divided into 2 subgroups,MICT1(n=6)and MICT2(n=8).The MICT group performed moderate intensity sustained power cycling based on the CTL group for 24 weeks,with the MICT1 subgroup training at 60% to 67% VO2 max and the MICT2 subgroup training at 68% to 75% VO2 max.The total amount of exercise per week was controlled at 1500 kcal and required 4 training sessions of 40 min each,maintaining a cycling rate of 60 r/min during each session.The HIIT group performed high intensity intermittent power cycling based on the CTL group,with a training cycle of 24 weeks,total aerobic training was controlled at 1500 kcal,exercise intensity was alternated between 80%-90% VO2 max and 40%-50% VO2 max in a ratio of 4:3 for a total of 4 sets,i.e.4min 80%-90% VO2 max,3min of 40%-50% VO2 max,and a cycling rate of 60 r/min,28 min each time,4 sets,3 times a week.Exercise endurance was assessed using a cardiopulmonary exercise test and VO2 max was recorded.lower limb strength was assessed using a 30 s continuous chair stand test.The Patient Health Questionnaire(PHQ-9)and the Generalized anxiety disorder-7(GAD-7)were used to assess mental health status.Repeated measures ANOVAs were conducted on data on cardiorespiratory endurance,lower limb strength and mental health in the CTL group,MICT1 subgroup,MICT2 subgroup and HIIT group before,at week 8,week 16 and week 24 after the intervention respectively.Results:(1)For weight and BMI,there was no significant difference between the CTL group compared to pre-intervention at all time points after the intervention(P > 0.05);there was a significant difference between the MICT1 subgroup,MICT2 subgroup and HIIT group compared to pre-intervention at all time points after the intervention(P < 0.05),and no significant difference between two comparisons at all time points after the intervention(P >0.05).There was no significant difference between the two groups after the intervention(P >0.05).(2)In terms of cardiopulmonary endurance,there was no significant difference between the CTL group and pre-intervention at all time points after intervention(P>0.05);VO2max increased in the MICT1 subgroup,MICT2 subgroup and HIIT group at week 24 compared to pre-intervention,week 8 and week 16 after intervention(P<0.05);VO2max increased in the MICT2 subgroup and HIIT group at week 16 compared to pre-intervention(P<0.05);VO2max increased(P<0.05);VO2max increased(P<0.05)in the HIIT group at week 16 and week 24 after intervention compared with week 8,and VO2 max increased(P<0.05)at week 24 after intervention compared with week 16;there was no significant difference between the two compared with each other at the remaining time points(P>0.05).After the intervention,there was no significant difference between the groups at week 8(P>0.05);at week 16,there was a significant difference between the HIIT group and the MICT1 subgroup and the CTL group(P<0.05),no significant difference between the HIIT group and the MICT2 subgroup(P>0.05),and no significant difference between the other groups(P>0.05);at week 24,there was a significant difference between the HIIT group and the MICT2 subgroup(P>0.05).At week 24,there was a significant difference between the HIIT group and the MICT1 subgroup and the CTL group(P<0.05),between the MICT2 subgroup and the CTL group(P<0.05),and no significant difference between the HIIT group and the MICT2 subgroup(P>0.05),and between the other groups(P>0.05).(3)Regarding lower limb strength,there was no significant difference between the CTL group compared with pre-intervention at each time point after the intervention(P>0.05);lower limb muscle strength increased in the MICT1 subgroup,MICT2 subgroup and HIIT group at week 24 compared with pre-intervention(P<0.05);lower limb muscle strength increased in the HIIT group at week 16,week 8 compared with pre-intervention(P<0.05),and week 24 after the intervention compared with week The lower limb muscle strength increased at week 8 compared to week 8(P<0.05)and at week 24 compared to week 16 after the intervention(P<0.05);the remaining time points were not significantly different between the two compared to each other(P>0.05).After the intervention,lower limb muscle strength improved in the MICT1 subgroup,MICT2 subgroup,and HIIT group compared with the CTL group at week 8,week 16,and week 24(P<0.05);there was no significant difference between the other groups compared(P>0.05).(4)In terms of mental health GAD-7,there was no significant difference between the CTL group and the pre-intervention group at each time point after the intervention(P>0.05);anxiety levels decreased in the MICT1 subgroup,MICT2 subgroup and HIIT group at week 24 compared with the pre-intervention group,week 8 and week 16 after the intervention(P<0.05);the rest of the time points were not significantly different between two comparisons(P>0.05).After the intervention,at week 8,there was no significant difference between the groups(P>0.05);at week 16 and 24,anxiety levels decreased in the MICT1 subgroup,MICT2 subgroup and HIIT group compared with the CTL group(P<0.05)and there was no significant difference between the other groups(P>0.05).(5)In terms of mental health PHQ-9,there was a significant difference(P < 0.05)between the CTL group at week 8 and week 16 after the intervention compared with the pre-intervention,and no significant difference(P > 0.05)between two comparisons at other times;there was a significant difference(P < 0.05)between the MICT1 subgroup,MICT2 subgroup and HIIT group at various time points after the intervention compared with the pre-intervention,and no significant difference(P<0.05)between two comparisons at other times.significant differences(P>0.05).After the intervention,there was no significant difference between the groups at week 8 and 16(P>0.05);at week 24,there was a significant difference between the MICT1 subgroup,MICT2 subgroup and HIIT group compared with the CTL group(P<0.05),and no significant difference between the other groups(P>0.05).During the experimental period,the incidence of adverse events in all four groups was 0respectively.Conclusions:(1)Long-term high intensity intermittent and moderate intensity sustained power cycling both improved cardiorespiratory endurance,lower limb strength and mental health in sedentary university students.(2)Long-term high-intensity intermittent and moderate-intensity sustained power cycling both improved weight and BMI in sedentary university students.(3)In the long-term intervention,high-intensity intervals and moderate-intensity sustained power cycling were more effective than moderate-low intensity sustained power cycling. |
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