Table 3.

Summary of behavioral diagnosis using the TDF (quotes are taken verbatim from the systematic review).

TDF	Frequency* (% total)	Findings (barriers and facilitators)/why are children doing or not doing physical activity	Quotes
Environmental context and resources	32.4%	I have no time or peers to play with me for leisure-time exercise (B)	“I do not have time for leisure time exercise at all from Monday to Friday. I came home late from school in the evening, and when I finish my homework, it's time to sleep. I just don't have time to exercise at all”
		Salient consequences of participating in physical activity (B)	“The most frequently mentioned disadvantage, “will take too much time,” was mentioned by 40.6% of the students”
		Circumstances that make physical activity easy and circumstances that make it difficult (B, F)	“Many of the circumstances (e.g., assignments, time, and weather) were mentioned both as circumstances that make physical activity easy and as circumstances that make it difficult. The most frequently reported facilitator of physical activity, “having fewer assignments,” was mentioned by 27.7% of the students. The most frequently mentioned barrier, “having too many assignments,” was mentioned by about half (48.4%) of the students. Additionally, “time” was the second most frequently mentioned circumstance; 14.2% of the students mentioned having more time as a facilitator, and 18.8% mentioned not having enough time as a barrier. These data also suggest that “having fun activities,” “having others to participate with,” “approval from others” and “making facilities more available” operate as facilitating and hindering circumstances”
		“Academic-focused” school environment seemed to be a major barrier for PA participation (B)	“I personally think childhood obesity nowadays is due to the fact that kids eat too much and move too little. The environment now is so different from the environment of my childhood. My kid is sitting there all day studying and no time for exercise. It seems that he does not like exercise at all, and when he has spare time, he watches TV”
		Safety (crime) (B)	“Afraid of being taken or hurt at night”
		Safety (traffic) (B)	“Few cars on roads”
		Safety issue (B)	“Some dangerous activities, like skating, it's not too safe for my girl to play. Children usually can't decide what is dangerous for them. They just play for fun but neglect the importance of safety. For example, I won't let him go climbing hills or rock…it's too dangerous. I've seen quite a lot of accidents happened in people climbing, it's definitely not suitable for children, especially girls, it's just not right for her to play such rough sport and Hong Kong don't have much safe climbing places for younger ones and there is a lack of qualified teachers”
		Functionality (F)	“Convenient transportation”
		Other negative feelings (B)	“Too many students in a class (40–45 students sharing one basketball court)”
		Destination (F)	“Recreation grounds”
		Aesthetic (F)	“Fresh air”
		Others (B)	“Too many people in recreation grounds”
Social influences	21.6%	Families are an important factor in their physical activity participation (F)	“Doing physical activity is fun and when I see other people playing, I want to be one of them … My parents also encouraged me. They would spend time jogging with me and I still remember we had so much fun”
		Confucian father played a leading role in determining the different dimensions in his children's life (F)	“Interestingly, within the group we interviewed, only fathers provided actual facilitation of their children's physical activity. One of them acted as an assistant coach regularly in his boy's rugby team, while a few attended their children's sports competitions such as badminton and swimming during their leisure time, and two parents assisted with transporting children to playgrounds”
		Salient who approve referents (F)	“Clearly, most of the salient referents for this behavior were family members, including parents, others, fathers, and grandparents. Teachers and classmates were also mentioned by these middle school students. Doctors and other health professionals were not very frequently mentioned. Parents were the most frequently mentioned approving group and disapproving group and were mentioned more frequently as approving (42.6%) than as disapproving (27.7%)”
		High expectation of children's academic success (B)	“My son is now in the soccer team and he practices for many days a week … he comes back home at 7 pm and I think soccer is distracting him from studying well … I'm so afraid that he'll get hurt and I'm thinking not let him play anymore. I usually let him do whatever he wants in sports but if the exam is near, I'd advice him to play less basketball, I think it's better for him to spend more time studying than on playing”
		Physical activity to be another responsibility in their lives (B)	“There was a time a basketball club invited me to join them, and I know this was a chance for me to play at a professional level. However, my mother opposed my decision, and I did not dare to argue with her. Well, actually I don't really feel too regretful as I treated it as an interest. It only matters if I could play basketball happily or not. After practicing for a long time, I saw there was not much improvement, and I felt that I had reached the top already. Therefore, I gave up the interest in swimming”
		Make tailored objectives for students (F)	“We should combine the collective goal with the individual goal. Each student's physical quality and individual ability are different. We should fully consider the individual difference of each student when setting the teaching goal. When setting the collective teaching goal, we should make the goal has a certain range of fluctuation, because the requirement is universal for each student. We should ensure that students whose sports learning ability are not strong enough can improve their sports achievements through hard work and their interest in sports learning can be increased due to the establishment of motivation in sports learning. In the other way, this goal should also apply to those who have higher sports learning abilities”
		Strength the teaching and management regulation (F)	“The PE teachers should respect and care about students rather than criticize students at will. Teachers should equip a positive attitude and be the role model so that the students will feel the equality between themselves and teachers. In addition, they may be attracted to the class. With the establishment of a harmonious relationship between students and teachers, students will thus take the teachers as examples and change their behavior”
		Lack of social support (B)	“I always do sport alone by myself and this is why sport is not interesting to me. I do not like it because there is no one to compete with or compare with me. There is no one to encourage me and I do not feel happy when doing sport”
Beliefs about consequences	16.2%	Improving on their health (F)	“Physical activity is important because it is good for my health, I get less pain and disease after doing physical activities”
		Having positive outcomes for academic and/or career future (F)	“Sport may be useful for my future job because I will find sport-related careers, like being an athlete. I want to be as good as those Olympic athletes, I think they are gorgeous”
		Physical activity was not useful in relation to entering a better secondary school (B)	“Sometimes I think it [physical activity] is not really that useful at all as most schools do not think it is relevant to study”
		Physical activity had a lower priority than academic studies (B)	“I would like to excel in my academic studies. I think studies may affect my future but not the sport. I always place academic studies first”
		The importance of PE was linked closely to their children's academic advancement (F)	“PE is important because it makes my son healthier … good health may help him study better”
		Confucian beliefs in taking ‘good care’ of children (B)	“I used to do some sports and stretching exercises at home. I don't participate in too many activities now after I've had my child. I need to take care of her academic matters and other aspects of life such as driving her to a private tutoring center to learn English and taking a computer course after school. Therefore, I don't have much time to do exercise myself. I know doing more physical activity is good for my child, but I'd rather have her study first and only allow her to play for a while if she could finish her school work. You know, too much play will negatively affect her academic performance”
Memory, attention and decision process	8.1%	Feeling too tired after doing physical activity (B)	“I need to put in too much effort in sport. I do not like the feeling of tiredness after doing sport”
		I exercise only during the physical education (PE) class, and I exercise primarily to pass the high school entrance examination, commonly known as “Zhongkao.” (B)	“We have a morning recess. Usually, we start with group rhythmic gymnastics and then jump roping. We have PE class, and each class content is arranged by teachers for us to run or do items for Zhongkao. We are not given free play time during PE class. I like playing badminton, but my PE teacher said I can only play badminton after I am capable of receiving full credits for all Zhongkao-tested items”
		Complained about the teacher and the curriculum (B)	“Having academic subject lessons at the expense of PE lessons, especially when it comes to the senior secondary level”
Emotion	5.4%	Overly skill-oriented nature of their classes (B)	“It's not very nice because we always learn traditional sports, such as track and field, soccer, basketball, volleyball, and gymnastics. It is no fun at all. Teachers are actually repeating the same content we have already learned in senior primary schools. I dislike running long distances; it is so boring”
		Insufficient time provision both in the school's physical education curriculum and after school hours (B)	“Well, it seems that during PE lessons, most of the time, about 15–20 min was allocated to doing stretching and warm-up, and the time for us to really learn a sport is not enough”
Belief about capabilities	5.4%	Feeling happy and competent and enjoying the sport and movement (F)	“I feel satisfied when I can shoot a basketball into the ring … and usually, I am able to hit the shuttlecock with a swift sound and therefore I feel really happy and have fun playing with it … When I play badminton, I think the sound of hitting a badminton cock is really interesting, I feel very happy when I could hit the cock with that kind of special sound”
		High attainment value and high utility in physical activity (F)	“I can boast in front of my teammates in basketball, which I think is important for me to do better in it”
Goals	2.7%	As they grew up, time spent on a particular physical activity increased (F)	“I play table tennis more now and therefore have less time for other activities. I'd rather focus my time on improving in it than spending time doing various sports which seem to be wasting my time”
Skills	2.7%	Lack of perceived improvement in physical activity (B)	“I do not feel any differences or improvements and I think it is boring. I am always like that, not a bit better”
Knowledge	2.7%	An instrumental orientation to physical activity engagement (F)	“Students in Hong Kong, as far as I know, are not doing much sports and exercise. I'm sure exercise can help my son to be fit and maintain a good shape and weight”
Social/professional role and identity	2.7%	Parental work commitment (B)	“Both of us need to work 6 days a week, well… we're not rich and we must work for the money for the family. Sometimes we would go out with the kids on Sundays and we usually go shopping or dining out”

B, barrier; F, facilitator.

^*%, the percent (count) of statements coded to each specific TDF domain, out of the total identified statements.