Much evidence has indicated that adherence to the 24 h movement guidelines (physical activity, screen time and sleep) is associated with physical health, while little is known about the adherence to the 24 h movement guidelines and self-reported physical fitness in adolescents. This study, therefore, aims to explore the association between the 24 h movement guidelines (in isolation or combination) and self-reported physical fitness in a sample of Chinese adolescents in an age range of 10–17. Methods: A convenient sample of 3807 children and adolescents from 12 schools was adopted in the present study. A questionnaire based on the Health Behaviour in School-aged Children was used to assess physical activity and screen time, and the Pittsburgh Sleep Scale was utilized to measure sleep duration. The International Fitness Scale was used to assess physical fitness in study participants. Ordinal logistic regression was performed to estimate the association between adherence to the 24 h movement guidelines and self-reported physical fitness. Results: Of all study participants, 0.9% of them met the 24 h movement guidelines, and meeting the guidelines was significantly associated with higher levels of self-reported physical fitness. The analysis for the association between specific combinations of 24 h movement guidelines and self-reported physical fitness underscored the importance of meeting the physical activity recommendations. Conclusion: Adherence to more recommendations contained in the 24 h movement guidelines was associated with higher self-reported physical fitness, especially cardiorespiratory fitness and muscular strength. Our study also stressed the importance of promoting moderate to vigorous physical activity in children and adolescents. Further works should focus on the association of a recommendation of adherence with other health indicators and replicate this study on larger samples among Chinese children and adolescents. Additionally, longitudinal or interventional studies that include more socio-demographic factors are needed to explore the association between 24 h movement guidelines and self-reported physical fitness, and the 24 h movement guidelines also should be promoted on a large scale in Chinese children and adolescents. Moreover, it is also needed to gain better insights into the directionality of the relationship between compliance with 24 h movement guidelines and self-reported physical fitness, as well as the mechanisms underlying the associations in Chinese children and adolescents.

Purpose: To explore the influencing factors that restrict the exercise behavior of children and adolescents, investigate the effect of subjective exercise experience on exercise behavior, and reveal the mediating effect of exercise commitment between subjective exercise experience and exercise behavior so as to promote children and adolescents to maintain good health exercise habits and improve their physical and mental health. Methods: The Subjective Exercise Experience Scale (SEES), Exercise Commitment Scale (ECC), and Physical Exercise Rating Scale (PARS-3) were used to conduct a questionnaire survey on 600 children and adolescents in Chongqing, China, and SPSS21.0 and AMOS21.0 statistical analysis software was used to carry out statistics and analyses on the questionnaires. Results: (1) Among children and adolescents, boys’ exercise commitment and exercise behavior were significantly higher than girls’, and there was no significant gender difference in subjective exercise experience. The exercise behavior of children and adolescents aged 9–12 was significantly higher than that of children and adolescents aged 13–15, and there was no significant age difference in subjective exercise experience and exercise commitment. (2) There was a significant correlation between the subjective exercise experience, exercise commitment, and exercise behavior of children and adolescents, and subjective exercise experience could directly and positively predict exercise commitment (β = 0.63) and exercise behavior (β = 0.57)—exercise commitment could also directly and positively predict exercise behavior (β = 0.52). (3) The exercise commitment of children and adolescents has a partial mediating effect between subjective exercise experience and exercise behavior (accounting for 37.50% of the total effect), and has a mediating effect between different exercise amounts, with the strongest mediating effect being on high exercise amount (32.10% of the total effect). Conclusions: The exercise behavior of children and adolescents was not only directly affected by subjective exercise experience, but also affected by the mediating effect of exercise commitment, and maintaining a good exercise experience and commitment was an effective way to effectively improve exercise behavior and amount of exercise in children and adolescents.