Effects of a Tabata-style functional high-intensity interval training intervention on cardiometabolic risk factors and physical activity in female university students

The primary aim of this thesis was to examine the effects of a novel Tabata-style functional high intensity interval training (HIIT) on cardiometabolic health and physical activity (PA) in female university students. 

Study 1 was a meta-analysis review to explore the association between objectively measured PA with adiposity and cardiometabolic health in adult women. objectively determined PA in terms of steps, total physical activity (TPA) and moderate-to-vigorous intensity physical activity (MVPA) were favorably associated with adiposity outcomes. The improvement in adiposity can be achieved by simply accumulating more PA than previously and adiposity is more likely to be benefited by PA performed at higher intensity.  Furthermore, it was most compelling and consistent that being more physically active was beneficial to the metabolic syndrome. Overall, PA level was low in adult women, suggesting that increasing TPA was more important than emphasizing the intensity and duration of PA. 

Study 2 and study 3 were pilot studies and data from these studies was used to evaluate the effectiveness and feasibility of the Tabata-style functional HIIT. 

Findings from Study 2 showed that, after a 12-week intervention, the Tabata-style functional HIIT was equally effective in improving cardiorespiratory fitness and body composition compared to the running based HIIT. Additionally, this novel HIIT was able to induce a required high-intensity exercise response and provide a more enjoyable training experience for the participants. 

Findings from Study 3 indicated that untrained female university students were able to achieve the target high intensity responses. Moreover, the novel HIIT resulted in simultaneous increases in sedentary time, MVPA and TPA in the short term. 

Study 4 showed that dairy intake, MVPA and TPA were all independently associated with systolic blood pressure, indicating that dietary intake was a contributor to cardiometabolic health independent of exercise. 

Study 5 evaluated the effects of a 12-week Tabata-style functional HIIT program (Project: Just Four Minutes) on multiple cardiometabolic biomarkers and habitual PA in female university students. A mixed linear model was used to assess the intervention effects. After the intervention, compared to the control, there were large intervention effects on maximal oxygen uptake, resting heart rate, systolic blood pressure, MVPA, TPA; moderate effects on percentage body fat, fat mass, high-density lipoprotein, total cholesterol; small effects on body mass index, waist circumference, low-density lipoprotein, HOMA-IR and fasting insulin. Only the percentage change of high-density lipoprotein was associated with the change of MVPA and TPA. Conclusively, this project appeared to be a feasible and effective way to improving cardiometabolic health and PA in female university students.