Establishing patterns of physical activity during childhood and adolescence is important for immediate gains in health and well-being and to develop positive behaviors that can be deployed throughout the life course. Concern about increased levels of childhood overweight and obesity and whether this pattern will continue into adolescence underscores the importance of being physically active (Dishman, Sallis, & Orenstein, 1985; Sallis, Prochaska, & Taylor, 2000; U.S. Department of Health and Human Services, 1996). However, studies report a decline in physical activity levels during adolescence (Allison, Dwyer, & Makin, 1999a, b; Frankish, Milligan, & Reid, 1998). This decline occurs more sharply among girls, with girls being less physically active than boys (Allison & Adlaf, 1997; Allison et al., 1999b; Garcia, Pender, Antonakos, & Ronis, 1998; Higgins, Gaul, Gibbons, & Van Gyn, 2003; Sallis et al., 2000; Trost et al., 2002). Thus, it is important to understand what makes it difficult for adolescent girls to participate in physical activity.
Quantitative and qualitative studies have examined barriers and other factors that influence physical activity among adolescent girls. Quantitative studies have focused on correlates and predictors of physical activity, exercise, and sport such as gender (Frankish et al., 1998; Higgins et al., 2003; Sallis et al., 2000), age (Frankish et al., 1998; Higgins et al., 2003; Sallis et al., 2000), achievement orientation (Sallis et al., 2000), perceived competence (Sallis et al., 2000), lack of motivation (Robbins, Pender, & Kazanis, 2003; Saxena, Borzekowski, & Rickert, 2002; Sherwood & Jeffery, 2000; Tappe, Duda, & Ehrnwald, 1989), social support (Frankish et al., 1998), lack of time (Allison et al., 1999b; Robbins et al., 2003; Saxena et al., 2002; Tappe et al., 1989; Tergerson & King, 2002), and previous involvement in physical activity or community sports (Sallis et al., 2000). Qualitative studies of barriers to physical activity among adolescent girls suggest that the barriers are specific to the adolescent stage (Coakley & White, 1992; Culp, 1998; Harris, 1993; Humbert, 1995; Sleap & Wormald, 2001). For example, adolescent girls reported barriers such as: gender roles, peer influence, and self-concept (Culp, 1998); parents and opposite-sex friends (Coakley & White, 1992); lack of self-confidence (Culp, 1998; Sleap & Wormald, 2001); and lack of time (Sleap & Wormald, 2001). Also, they reported their physical education classes involve uncomfortable physical exertion (Harris, 1993) and ridicule and embarrassment (Humbert, 1995).
The purpose of this study was to explore perceived barriers to physical activity participation among adolescent girls who live in a large ethnoracially and socioeconomically diverse city. While other studies (Robbins et al., 2003; Saxena et al., 2002; Tappe et al., 1989) have examined the issue of barriers to physical activity among adolescent girls, the present study is different in that multi-ethnic groups of adolescent girls participated in focus groups to provide indepth qualitative data. This study is one component of a comprehensive assessment of barriers to physical activity among Canadian youth conducted by this research team. Also, results of this study were to be used to plan other components such as interviews with adolescents and a national survey of youth aged 13-18.
During the recruitment phase, interested adolescents completed a background information survey consisting of questions regarding their gender, age, current grade, and ethnoracial origin. Seventy-three adolescent girls from four secondary schools in different regions of Toronto participated in I of 7 focus group sessions. Toronto has a population of approximately 2.4 million which includes over 90 ethnocultural groups (City of Toronto, n.d.). Participants were selected to ensure ethnocultural diversity in each session. Participants' ethnoracial origins were Asian (35%), White (24%), Black (22%), Latin American (1%), other (8%), and multi-racial (10%). Participants were mostly 15- and 16-year-olds in grades 10 and 11.
A structured interview guide began with showing and describing Canada's Physical Activity Guide to Healthy Active Living diagram that explains the type, intensity, and duration of physical activity needed to maintain health (Public Health Agency of Canada, 2003, October 8). Three topics were examined in the focus groups. First, participants were asked why they do moderate and vigorous physical activity, even if done seldomly. Second, they were asked to discuss what makes it difficult for them to do moderate and vigorous physical activity. Third, they were asked to suggest what needs to happen in their community to help them and other adolescents become more physically active. The findings reported here deal with the second topic. To pilot test the focus group interview guide, eight Toronto Public Health (TPH) staff who provide physical activity programs in the community, and two adolescents commented on whether the questions were relevant and clear and elicited discussion.
The University of Toronto and a Toronto school board provided ethical approval for the research protocol. TPH nurses promoted the study by describing it in classes in the four schools, leaving information packages in the classrooms for those interested in participating, and informing students that additional packages were available in the main office. A package consisted of a student informed consent form, a parent/guardian consent form, a brief student survey to collect background information, and an envelope addressed to the main offices. Posters and main office announcements were also used to promote the study. TPH nurses picked up 127 completed forms from the main offices. Eighty-two interested adolescents were selected as potential participants to ensure that each group was diverse in age, grade, and ethnoracial origin. About two weeks before the focus group session, they were telephoned to inform them when the session would be held. A reminder telephone call was made the evening before the session.
Ninety-minute focus groups were conducted in the schools during the fall of 2001. Between 8 and 12 adolescents participated in each session. An experienced moderator facilitated the sessions, while an assistant audiotaped the sessions and took notes. Verbatim audiotapes were transcribed following a specific protocol (Poland, 1995). Two transcripts were compared to their audiotapes for quality control. All transcripts were imported into The Ethnograph (Qualis Research Associates, 1998). The research team used a constant comparison approach to develop themes, which involved coding comments by continually referring to previously coded comments for comparison (Flick, 1998; Morse & Richards, 2002). Two research assistants and the first author independently read the seven transcripts and inductively generated a list of themes with descriptive comments. They compared and discussed the themes and agreed on a common list of themes with accompanying codes. Both assistants independently re-read two transcripts, applying codes to text. Coding discrepancies were discussed until agreement was reached. One assistant coded the remaining transcripts.
A number of factors make it difficult for participants to be active. These were: lack of time; involvement in technology-related activities; influence of peers, parents and teachers; concern about safety; inaccessibility of facilities and cost of using them; competition; and body-centered issues.
Lack of Time
Participants identified lack of time as one of the main barriers to participating in physical activity; they mentioned homework, a parttime job, and family responsibilities. Participants in all sessions reported having a lot of homework; some said that they have about four hours of homework on some days. For example, a participant said:
I don't have the time [to do physical activity]. I get home from school and I do homework. Then I have dinner, do homework, and then I go to bed. That's pretty much the way it goes five days a week. On Saturday and Sunday, my parents try to get me to do things with them. So there's absolutely no room for anything else.
Students enrolled in a more academic-stream program reported having an even more demanding workload. Several asserted that their choice to be active was based on their priorities. For example, some participants stated that they do little physical activity because they consider school and homework of higher priority.
I'm really into a good education, doing my homework. I go home and once I have my snack, I just do homework until dinner and then I do homework until I sleep. I'm not going to put in anything [physical activity] here. I have to do my homework if I want to graduate from high school. I have no time for anything else.
Some participants said that, like homework, a part-time job is more important than physical activity. Several reported that their part-time job was important because of financial circumstances at home. For example, one commented that her part-time job money was sometimes used to buy groceries for the family. Another said:
My mom is very ill. She has brain cancer so she can't work very often. My stepfather is only working in the house. There are a lot of people in the house [older brothers and sisters] so it means that you have to buy a lot of food and a lot of extra things. My mom and stepdad are sort of struggling with money. They can pay rent but when it comes to cable and phone money, they might be short. So I say, "You keep your money and I'll pay for it [from part-time job money]." ... I think that I should be helping my mom through things when she's sick.
Students' part-time work left little time for physical activity, even when motivated to be active. For example:
There are things that hold me back, like work. Work is a big issue because you can't tell them, "Oh well, that's when I go to the gym, at night." They don't care. You're scheduled and you're going to have to work.
Participants described a demanding work schedule after school and on weekends. Some worked approximately 10 hours a week. Some said that, upon returning home from work, they did homework, which left little or no time for physical activity. Some participants who worked part-time were so tired that it created problems at school such as falling asleep in classes.
Participants said that their responsibilities at home made it difficult for them to find time for physical activity. They reported helping with household chores such as cleaning, cooking, and caring for younger siblings, which included helping with homework. One commented: "My parents go to work at night. I have two little twin brothers to take care of. So my parents are not home. So I feed them, wash the dishes, and clean up the house."
Involvement in Technology-related Activities
Some participants preferred spending time on the telephone and internet and watching television, which left little time for physical activity. Sometimes, it was difficult to get together with friends because they lived far away and it took a long time to get there by public transit. However, since keeping in touch with friends was important to them, they spent a lot of time talking with them on the telephone and "chatting" with them on the internet. Typical comments were:
Whenever my friends and I have free time, we just talk on the phone. We don't go, "Oh let me get off, I have to do some activity." We just talk about nothing basically. It's like hours and hours on the phone if we have free time. When you go on the internet, you can't get off. I go on the internet and I just talk with my friends on-line. I've never really thought about going out for a walk or something to relax. It's easier if you just sit in front of the TV and start pushing buttons and wait for something to come on.
Influence of Peers, Parents, and Teachers
Some mentioned that peers, family and family culture, and teachers influence their participation in physical activity. They noted that not having someone to join them in physical activity was a deterrent. Also, they described the pressure in choosing to go out with friends or participate in physical activity without them. For example, one said that her friends get angry at her for choosing to play sports rather than spend time with them. Another explained how peer pressure influences physical activity participation.
Your friends influence how active you are. If you hang out with a certain group of friends who feel it's not worth being active and there's no point to it, you won't be active because you want to fit in with your friends. But if you have friends who are very self-conscious about being active, then you'll also be that.
Some participants said that physical activity sometimes takes away their time spent with boyfriends.
Some mentioned that parents' expectations influenced their decision to be or not be physically active. A few noted that their parents are role models and that parents' level of physical activity influences their activity level. Some explained that their parents prefer them to be at home and to do homework, rather than physical activity. Other participants said that their parents not only do not encourage them but discourage them from engaging in physical activity. For example:
I also think parents come into it too because I wanted to take gym this year and you have to have a form your parents sign that says it's okay to take these courses. But my dad didn't want me taking gym. He thought that business courses were more important than gym.
Similarly, another participant stated that she had to convince her parents to allow her to participate in physical activity. Another said, "Now that I'm older, I can't just do what I want to do--play with my friends, go out, and play sports. My father says I should be older and 'settle down'."
There were participants who felt that some teachers did not encourage girls to participate in sports. For example, one said that she wanted to play football but a teacher discouraged her from playing it. Another stated that some teachers would not let girls play soccer with boys because "they'll be too rough on you."
Concern about Safety
Some participants reported that their parents' concern about their safety deterred them from participating in physical activity after school or evenings. They said that their parents were concerned about the possibility of sexual assault and kidnapping, and wanted them to return home before dark. A participant commented:
I used to play soccer when I was younger. I'd say to my parents "I'm going to the park" and they didn't really mind. But now that I'm sort of more grown up, they watch the news too much I guess, and all of a sudden it's like "Last time at this other park, something happened. We don't want you there." They're overprotective.
Some participants avoided using facilities that they perceived to be unsafe. For example, they did not use a local basketball court because it was a "hang-out for gangs." Similarly, a participant said:
If you have a community center, if it's got a bad name, you don't want to go there. That's because you don't know what's going to happen to you. If you go there, someone is going to hurt you or something.
Inaccessibility of Facilities and Cost of Using Them
Inaccessibility and cost of using facilitates were mentioned as barriers to physical activity. Some mentioned that there were no recreation centers in the neighborhood. Also, transportation to facilities located far from home was identified as a barrier. Some had difficulty getting to facilities by using public transportation or relying on parents who were not always available to drive them. One stated:
There's a bus that comes by my house every half hour but if I take it, it takes a really long time to get home. And unless my parents give me a drive, it's really hard for me to get anywhere and a lot of the [recreation] programs that I'd like to take are downtown. So you'd be two hours just trying to get down there and then still have to try to get back. It's just too tiring to do that.
Several participants stated that they decided to stay home instead of engaging in physical activity outside because of cold weather. Some reported that sports such as football were not available to girls and it was too expensive to join some community sports. For example:
I think that money is a big factor. I wanted to join a program and it cost $500. You have to pay for your travel and all that, so I just said, "Forget it. I'll stay home and watch TV."
Some participants mentioned lack of opportunity to take physical education classes in high school. They said that it was more difficult to be physically active when schools, operating on a semester system, only offer physical education during one semester, when physical education is not compulsory after grade nine, and when physical education is not an option in the academic stream. They also mentioned inconvenient practice times for school sports and outdated equipment as barriers.
On one hand, some participants disliked competition, reporting that it deterred them from participating in physical activity. They felt that the pressure to win in competitive sports was too stressful. Typical comments were: "If you're in a competitive sport, there's more stress than if you're just doing a sport for fun. There's more pressure to win or score the goal." and "I think that some people are afraid of not doing well in sports and that people will judge them on that." Some participants did not try out for school sports teams because they were anxious about the possibility of failing to make the team. For example, a participant said, "A lot of people are really good [in sports]. You think that you're good but when you see them, you think 'maybe I'm not good enough'... You just don't want to try sports." Others were discouraged when they tried but failed to make the team. Some preferred to be physically active "for the fun of it" rather than get involved in competition. On the other hand, some were motivated to participate in physical activity because of competition. They viewed it as an opportunity to prove themselves.
Participants discussed body-centered issues such as menstruation, stereotypes about femininity, and concerns about physical appearance as barriers to participating in physical activity. Some said it was difficult for them to be physically active during menstruation. For example, when asked what makes it difficult for you to be active, a participant responded: "friends, boyfriends, and having your period." Experiencing cramps and discomfort, not feeling energetic, and being concerned about "leaking" inhibited them from being physically active. A participant said, "When I'm menstruating, I don't want to go swimming. I don't want to jump up and down. I just feel weird. I just want to sit down ... I just hate it [menstruation]. I think it's disgusting ... I'm so uncomfortable."
Participants discussed some stereotypes about femininity related to physical activity., Some felt that there was a perception that active girls are not feminine. They felt that girls have to demonstrate masculine qualities, such as being a tomboy, to play sports. They asserted that they have to choose between being feminine and being physically active.
Some mentioned concerns about physical appearance as a barrier. They said that they cannot wear make-up to look good for others and be physically active. One noted, "What stops a lot of girls from doing sports is that they're worried about how they look, their make-up, and everything." Some did not participate because they felt self-conscious about their appearance in front of adolescent boys. They shared examples of discomfort such as when boys stared at them, when they wore shorts during the activity. One commented, "Guys are perverted. When you're doing jumping jacks, they're staring too hard. And guys want to run next to you if you have big boobs."
Participants identified various factors that make it difficult for them to be physically active--both perceived and actual. Sallis and Owen (1999) used an ecological model to show how multiple factors determine physical activity. This framework, which consists of intrapersonal factors, the social environment, and the physical environment, can be used to interpret the barriers identified in the current study.
Participants perceived lack of time as a barrier to physical activity, which can be viewed as an intrapersonal barrier. However, it seems that time and some other intrapersonal barriers can also be considered environmental barriers when they are related to external influences such as school demands. The current results are consistent with previous research in which lack of time was reported as a major barrier (Allison et al., 1999a,b; Culp, 1998; Frankish et al., 1998; Harris, 1993; O'dea, 2003; Robbins et al., 2003; Saxena et al., 2002; Sleap & Wormald, 2001; Taylor, Legrand, & Newton, 1999). Participants' concern about having little time to do physical activity because of school, work, and family responsibilities as well as competing interests in technology-related activities suggests that adolescents and others who influence their behavior need to give physical activity some priority. Adolescents need to be encouraged to increase their physical activity and decrease the amount of time they spend on sedentary activities such as using the internet and watching television. Lack of time is not simply a time management issue, since several participants spoke of the multiple time demands of school, work, and home responsibilities. Lack of time for physical activity highlights the key role that schools play in offering physical education classes, which may be one of the few opportunities for some adolescent girls to be physically active.
The finding that disliking competition and being anxious about not doing well in sports made it difficult to participate in physical activity is consistent with previous research. For example, other researchers found that a previous bad experience or dislike of exercise (Harris, 1993; Saxena et al., 2002; Taylor, Legrand, & Newton, 1999) or physical education (Coakley & White, 1992; Sleap & Wormald, 2001; Taylor et al., 1999), and feeling inadequate or incompetent (Harris, 1993; Sleap & Wormald, 2001; Taylor, Legrand, & Newton, 1999) were barriers to physical activity. Self-efficacy is a consistent predictor of physical activity among adolescents (Allison et al., 1999b), and thus, promotion of physical activity among adolescents should include interventions designed to increase self-efficacy in physical activity.
Participants' discussion of body-centered issues such as menstruation, stereotypes about femininity, and concerns about physical appearance relate to both intrapersonal and environmental barriers to physical activity. This finding is consistent with other research which found that adolescent girls were self-conscious about their appearance particularly when adolescent boys were watching them (Leslie et al., 1999; Sleap & Wormald, 2001; Taylor et al., 1999) and intimidating them verbally during co-ed activities (Clough, McCormack, & Traill, 1996; Taylor, Legrand, & Newton, 1999). Physical activity interventions that address multiple issues such as realistic body images and self-esteem may be appealing to adolescent girls. Offering more physical activity programs that are for girls only and offering more noncompetitive programs that emphasize fun and skill development could facilitate their participation.
The extent to which peers, parents, and teachers influenced involvement in physical activity reflects social-environmental barriers. This finding was consistent with other studies in which peer influence (Allison & Adlaf, 1997; Culp, 1998; Taylor, Legrand, & Newton, 1999) and lack of social support (Frankish et al., 1998; O'dea, 2003; Taylor et al., 1999) were barriers to physical activity among adolescent girls. In the current study, some parents' perceived gender roles, such as the perception that their daughters should be involved in domestic activities rather than physical activity, deterred their daughters from being physically active. Similarly, adolescent girls in other studies reported that parental constraints (Coakley & White, 1992), feeling constrained by gender roles or social norms (Culp, 1998), and perceptions of gender-appropriate roles influencing expectations placed on adolescents (Culp, 1998; Taylor, Legrand, & Newton, 1999) were barriers to physical activity. The current results suggest that a supportive social environment will make it easier for adolescent girls to engage in physical activity. Considering the importance of hanging out with friends, promoters of physical activity could develop and implement physical activity programs that encourage adolescents to drop by with their friends and participate. Lifelong benefits of physical activity, such as spending time with friends, could be emphasized to encourage adolescent girls to be more physically active. Also, the results underscore the importance of their having active female role models at home, school, and elsewhere. Addressing these interpersonal factors and accommodating cultural differences will facilitate participation in physical activity.
The finding that some participants did not engage in physical activity because facilities were inaccessible and]or costly and that physical activity opportunities in school had been decreased, are consistent with recent studies (Fein, Plotnikoff, Wild, & Spence, 2004; Sallis, Conway, Prochaska, McKenzie, Marshall, & Brown, 2001). To understand the context of this research, it was conducted at a time when the provincial education system was undergoing considerable curriculum reforms, budget constraints, and labor disputes with the teachers' union. Teachers in Toronto discussed these factors in a recent focus group study that examined barriers to implementing physical activity curriculum guidelines (Dwyer et al., 2003). Also, in light of the media coverage of assaults on children during the time the study was done, it is not surprising that participants said that their parents were concerned about their safety. The current results suggest that physical activity promotion initiatives should focus on increasing the availability and accessibility of facilities in safe neighborhoods.
Interestingly, the current results do not support the view that different groups of adolescents (i.e., from diverse ethnic backgrounds) face different barriers and that each group should be examined separately (Robbins et al., 2003; Sallis et al., 2000). The current results showed that participants in all the focus groups perceived similar barriers though they sometimes differed in how they overcome them. Conducting research on ethnically diverse participants makes the current results more generalizable.
There are some limitations to this study. First, youth in an urban school setting participated in the focus groups, which limits the generalizability of the findings. Second, since the study focused on perceived barriers, it is not possible to determine whether these barriers would be the same for others. Both perceived and actual barriers, such as documentation of school-based physical activity opportunities, could be examined in future research. Third, participants offered their perceptions of how significant others such as parents influenced their involvement in physical activity. It would have been insightful to obtain responses from these others.
The involvement of TPH nurses who provide services in schools facilitated the utilization of the results; the findings were shared with TPH nurses who subsequently used them to develop and implement physical activity interventions for adolescent girls in school.
The authors thank Audrey Campbell, Sandy FitzGibbon, Valerie Gauer, Carmen James-Henry, Irene Kassies, Sandra MacMillan, Sari Simkins, and Voula Varsamidou from Toronto Public Health for their contribution in organizing the focus group sessions.
The Social Sciences and Humanities Research Council of Canada provided funding for this study (#828-1999-1040).
Allison, K. R., & Adlaf, E. M. (1997). Age and sex differences in physical inactivity among Ontario teenagers. Canadian Journal of Public Health, 88, 177-180.
Allison, K. R., Dwyer, J. J., & Makin, S. (1999a). Perceived barriers to physical activity among high school students. Preventive Medicine, 28, 608-615.
Allison, K. R., Dwyer, J. J., & Makin, S. (1999b). Self-efficacy and participation in vigorous physical activity by high school students. Health Education Behavior, 26, 12-24.
City of Toronto. (n.d.). Cultural diversity. Retrieved July 13, 2005, from http://www.city.toronto.on.ca/quality_of_life/diversity.thm
Clough, J., McCormack, C., & Traill, R. (1996). Girls playing soccer: A case study. ACHPER Health Lifestyles Journal, 43, 19-23.
Coakley, J., & White, A. (1992). Making decisions: Gender and sport participation among British adolescents. Sociology of Sport Journal, 9, 20-35.
Culp, R. H. (1998). Adolescent girls and outdoor recreation: A case study examining constraints and effective programming. Journal of Leisure Research, 30, 356-379.
Dishman, R. K., Sallis, J. F., & Orenstein, D. R. (1985). The determinants of physical activity and exercise. Public Health Reports, 100, 158-171.
Dwyer, J. J. M., Allison, K. R., Barrera, M., Allison, K., Ceolin-Celestini, S., Koenig, D., et al. (2003). Teachers' perspective on barriers to implementing physical activity curriculum guidelines for school children in Toronto. Canadian Journal of Public Health, 94, 448-452.
Fein, A. J.,. Plotnikoff, R. C., Wild, T. C., & Spence, J. C. (2004). Perceived environment and physical activity in youth. International Journal of Behavioral Medicine, 11, 135-142.
Flick, U. (1998). An introduction to qualitative research. Thousand Oaks, CA: Sage.
Frankish, C. J., Milligan, C. D., & Reid, C. (1998). A review of relationships between active living and determinants of health. Social Science and Medicine, 47, 287-301.
Garcia, A. W., Pender, N. J., Antonakos, C. L., & Ronis, D. L. (1998). Changes in physical activity beliefs and behaviors of boys and girls across the transition to junior high school. The Journal of Adolescent Health, 22, 394-402.
Harris, J. (1993). Young people's perceptions of health, fitness and exercise. British Journal of Physical Education Research Supplement, 13, 5-9.
Higgins, J. W., Gaul, C., Gibbons, S., & Van Gyn, G. (2003). Factors influencing physical activity levels among Canadian youth. Canadian Journal of Public Health, 94, 45-51.
Humbert, M. L. (1995). On the sidelines: The experience of young women in physical education classes. Avante, 1, 58-77.
Leslie, J., Yancey, A., McCarthy, W., Albert, S., Wert, C., Miles, 0., et al. (1999). Development and implementation of a school-based nutrition and fitness promotion program for ethnically diverse middle-school girls. Journal of American Dietetic Association, 99, 967-970.
Morse, J. M., & Richards, L. (2002). Readme first for a user's guide to qualitative methods. Thousand Oaks, CA: Sage.
O'dea, J. A. (2003). Why do kids eat healthful food? Perceived benefits of and barriers to healthful eating and physical activity among children and adolescents. Journal of the American Dietetic Association, 103, 497-501.
Poland, B. D. (1995). Transcript quality as an aspect of rigor in qualitative research. Qualitative Inquiry, 1, 290-310.
Public Health Agency of Canada. (2003, October 8). Canada's Physical Activity Guide to Healthy Active Living. Retrieved July 13, 2005, from http:// www.phac-aspc.gc.ca/pau-uap/paguide/
Qualis Research Associates. (1998). The Ethnograph (Version 5.0) [Computer software]. Salt Lake City, UT: Qualis Research Associates.
Robbins, L. B., Pender, N. J., & Kazanis, A. S. (2003). Barriers to physical activity perceived by adolescent girls. Journal of Midwifery and Women's Health, 48, 206-212.
Sallis, J. F., Conway, T. L., Prochaska, J. J., McKenzie, T. L.,. Marshall, S. J., & Brown, M. (2001). The association of school environments with youth physical activity. American Journal of Public Health, 91, 618-620.
Sallis, J. F., & Owen, N. (1999). Physical activity and behavioral medicine. Thousand Oaks, CA: Sage.
Sallis, J. F., Prochaska, J. J., & Taylor, W. C. (2000). A review of correlates of physical activity of children and adolescents. Medicine and Science in Sports and Exercise, 32, 963-975.
Saxena, R., Borzekowski, D. L., & Rickert, V. I. (2002). Physical activity levels among urban adolescent females. Journal of Pediatric and Adolescent Gynecology, 15, 279/284.
Sherwood, N. E., & Jeffery, R. W. (2000). The behavioral determinants of exercise: Implications for physical activity interventions. Annual Review of Nutrition, 20, 21--44.
Sleap, M., & Wormald, H. (2001). Perceptions of physical activity among young women aged 16 and 17 years. European Journal of Physical Education, 6, 26-37.
Tappe, M. K.,. Duda, J. L., & Ehrnwald, P. M. (1989). Perceived barriers to exercise among adolescents. The Journal of School Health, 59, 153-155.
Taylor, T., Legrand, N., & Newton, J. (1999). Myth and reality: Exploring teenage schoolgirl sport participation. Journal of the International Council for Health, Physical Education, Recreation, Sport, and Dance, 35, 32-36.
Taylor, W. C., Yancey, A. K., Leslie, J., Murray, N. G., Cummings, S. S., Sharkey, S. A., et al. (1999). Physical activity among African American and Latino middle school girls: Consistent beliefs, expectations, and experiences across two sites. Women and Health, 30, 67-82.
Tergerson, J. L., & King, K. A. (2002). Do perceived cues, benefits, and barriers to physical activity differ between male and female adolescents? The Journal of School Health, 72, 374-380.
Trost, S. G., Pate, R. R., Sallis, J. F., Freedson, P. S., Taylor, W. C., Dowda, M., et al. (2002). Age and gender differences in objectively measured physical activity in youth. Medicine and Science in Sports and Exercise, 34, 350-355.
U.S. Department of Health and Human Services. (1996). Physical activity and health: A Report of the surgeon general. Atlanta, GA: Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion.
John J. M. Dwyer, PhD, Department of Family Relations and Applied Nutrition, College of Social and Applied Human Sciences, University of Guelph, Guelph, Ontario, and Public Health Research, Education and Development Program, Public Health and Community Services Department, Hamilton, Ontario.
Kenneth R. Allison, PhD, Department of Public Health Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario.
Ellie R. Goldenberg, MPH, Department of Public Health Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario.
Allan J. Fein, MSc, Department of Exercise Sciences, Faculty of Physical Education and Health, University of Toronto, Toronto, Ontario.
Karen K. Yoshida, PhD, Graduate Department of Physical Therapy and Graduate Department of Rehabilitation Science, University of Toronto, Toronto, Ontario.
Marie A. Boutilier, PhD, Centre for Research in Women's Health, University of Toronto, Toronto, Ontario.
Reprint requests should be sent to Dr. John Dwyer, Associate Professor, Department of Family Relations and Applied Nutrition, College of Social and Applied Human Sciences, University of Guelph, Macdonald Institute Building, Guelph, Ontario, Canada N1G 2 W1. E-mail: firstname.lastname@example.org…