Association Between Physical Activity, Sedentary Time, and Physical Fitness of Female College Students in China

AbstractPurpose Many studies have investigated the effects of Physical Activity (PA), Sedentary Time (ST), and Physical Fitness on human’s physical health and well-being. However, these findings have been inconsistent. In view of the significantly lower PA and PF levels of females than males in China, as well as limited research is available investigating a population of college female students who are influenced by Eastern culture and context. This study therefore explored the association between Physical Activity (PA), Sedentary Time (ST), and Physical Fitness (PF) in female college students in China. Methods 512 female college students from China participated in this study. The international PA questionnaire was used to investigate the PA and ST of participants. Participants were classified into (a) active versus inactive groups according to WHO PA Guidelines and as (b) low versus high sedentary groups according to the median of their sedentary time. Subsequently, participants were divided into four sub-groups: (a) active/low sedentary, (b) active/high sedentary, (c) inactive/low sedentary, and (d) inactive/high sedentary. The Chinese National Student Physical Fitness Test (CNSPFT) was used to assess participants’ body composition, cardiorespiratory fitness, speed, flexibility, muscular endurance, explosive power, and overall fitness. Based on the CNSPFT results, participants were then divided into fit versus unfit groups. The association between PA, ST, and PF was examined and analyzed using independent samples t-test, binary logistic regression, and multinomial logistic regression methods. Results Participants in the active group showed significantly higher cardiorespiratory fitness(p < 0.05) and overall fitness (p < 0.01) than the inactive group. Compared to the inactive group, participants in the active group were also less likely to be classified as unfit in terms of cardiorespiratory fitness (odds ratio (OR), 0.572; 95% confidence interval (CI), 0.384–0.852;p < 0.05). Relative to the inactive/high sedentary group, those in the active/low sedentary group (OR, 0.436; 95% CI, 0.251–0.755;p < 0.01) and the active/high sedentary group (OR, 0.544; 95% CI, 0.319–0.929;p < 0.05) were less likely to be classified as unfit in terms of cardiorespiratory fitness. Furthermore, those in the active/high sedentary group (OR, 1.658; 95% CI, 1.018-2.700;p < 0.05) and the inactive/low sedentary group (OR, 2.086; 95% CI, 1.155–3.768;p < 0.05) were more likely to be classified as unfit in terms of their flexibility. Conclusions There was a positive association between PA, cardiorespiratory fitness and overall fitness. There was also an association between PF and the combination of PA and ST. Specifically, the combination of more PA and less ST was associated with better cardiorespiratory fitness. The combination of more PA and more ST or the combination of less PA and less ST were also associated with worse flexibility. These findings suggest that increasing PA and decreasing ST simultaneously can improve the PF of Chinese female college students.