Table 4. A summary and synthesis of analytical theme by SEP.

Theme	Findings per SEP			Synthesis
	Low	Middle	High
Social support	Barriers lack of financial support lack of support for transportation physical activity not valued by family unstable and changing family structure Facilitators parental support changing family structure support from teachers support from friends	Barriers less opportunities to commute actively Facilitators financial support	Barriers academic pressure peer pressure Facilitators financial support participating with friends sport club membership parental support participating as a family	Across socioeconomic groups parents were perceived as a barrier to physical activity. Low-SEP adolescents attributed this to a lack of time and money and the prioritization of other aspects of life. Middle-SEP parents facilitated less active modes of transport and high-SEP parents prioritized academia. There were stark differences in family participation. Middle/high-SEP adolescents frequently mentioned a “whole family” approach to physical activity. This was not the case for low-SEP adolescents who were more reliant on the support from teachers, coaches and friends. Peer support was important facilitator across all groups, especially for making physical activity more enjoyable.
Accessibility and the environment	Barriers Lack of/poor quality facilities in local neighborhood Quality and safety of public transport Poor school facilities and activity provision Facilitators Local community centers	Barriers n/a Facilitators Good facility provision in local neighborhood Access to the countryside Neighborhood safety	Barriers n/a Facilitators Good facility provision in local neighborhood and school Variety of school provision Access to the countryside	Low-SEP adolescents' experiences of physical activity accessibility and the environment noticeably contrasted with those of middle- and high-SEP. Low-SEP adolescents discussed the limited provision of facilities in their local area, including transport, and the lack of safety. Middle- and high-SEP adolescents discussed their access to facilities in their local environment, safety and their access to countryside. High-SEP adolescents further describe the variety of physical activities they had access to at school.
Experiences of health and other behaviors	Barriers n/a Facilitators Understanding of the health benefits of physical activity Understanding of the environmental benefits of physical activity	Barriers Prioritizing other behaviors Social demands Facilitators n/a	Barriers Prioritizing other behaviors Lack of free time Facilitators n/a	The health benefit of physical activity was a dominant narrative among low-SEP adolescents, who discussed its positive impact on both long and short-term health. While middle- and high-SEP adolescents recognized the health benefits of physical activity, they tended to focus on other behaviors such as sleep, homework or social activities.
Gendered experiences	Barriers Concerns about appearance (female) Low self-esteem and anxiety (female) Parental Stereotyping (female) Lack of support from friends (female) Facilitators Sport which demonstrate skill (male) Mixed-gender activities (male) Same-gender activities (female)	Barriers Competition (inactive males and females) High intensity (inactive males) Facilitators n/a	Barriers Pressure to perform in front of males (female) Facilitators Same-gender activities (female)	Gendered experiences focused on the female perspective. Low and high-SEP females explained their preference for a same-sex physical activity environment, however their reasons for this were different. In contrast, middle-SEP adolescents only reported gendered experiences when describing themselves as inactive. Both genders discussed a dislike of physical activity; males attributed this to disliking competitive high-intensity activities, whereas females disliked the pressure of team activities.

Note: This table summarizes each analytical theme by SEP.