OBJECTIVE: Media images of men and women have become increasingly muscular, and muscle-enhancing techniques are available to youth. Identifying populations at risk for unhealthy muscle-enhancingbehaviors is of considerable public health importance. The current study uses a large and diverse population-based sample of adolescents to examine the prevalence of muscle-enhancing behaviors and differences across demographic characteristics, weight status, and sports team involvement. METHODS: Survey data from 2793 diverse adolescents (mean age = 14.4) were collected at 20 urban middle and high schools. Use of 5 muscle-enhancing behaviors was assessed (changing eating, exercising, protein powders, steroids and other muscle-enhancing substances), and a summary score reflecting use of 3 or more behaviors was created. Logistic regression was used to test for differences in each behavior across age group, race/ethnicity, socioeconomic status, BMI category, and sports team participation. RESULTS: Muscle-enhancing behaviors were common in this sample for both boys and girls. For example, 34.7% used protein powders or shakes and 5.9% reported steroid use. Most behaviors were significantly more common among boys. In models mutually adjusted for all covariates, grade level, Asian race, BMI category, and sports team participation were significantly associated with the use of muscle-enhancing behaviors. For example, overweight (odds ratio = 1.45) and obese (odds ratio = 1.90) girls had significantly greater odds of using protein powders or shakes than girls of average BMI. CONCLUSIONS: The use of muscle-enhancing behaviors is substantially higher than has been previously reported and is cause for concern. Pediatricians and other health care providers should ask their adolescent patients about muscle-enhancing behaviors.

Sport is a promising setting for obesity prevention among youth, but little is known about whether it prevents obesity. We reviewed research comparing sport participants with nonparticipants on weight status, physical activity, and diet. Among 19 studies, we found no clear pattern of association between body weight and sport participation. Among 17 studies, we found that sport participants are more physically active than those who do not participate. We found seven studies that compared the diet of sport participants with non-participants. These studies reported that youth involved in sport were more likely to consume fruits, vegetables, and milk, and also more likely to eat fast food and drink sugar-sweetened beverages and consume more calories overall. It is unclear from these results whether sports programs, as currently offered, protect youth from becoming overweight or obese. Additional research may foster understanding about how sport, and youth sport settings, can help promote energy balance and healthy body weight.

There is a paucity of research regarding the contextual factors that influence health behaviors to inform the development of programs and services for youth during the transition from adolescence to young adulthood. Researchers are thus in need of efficient strategies for surveying diverse populations of young adults. This study among a population-based sample of young adults aimed to 1) examine response to a mixed-mode survey design (web and mailed surveys) and 2) identify demographic correlates of response mode. Young adults who participated in previous study waves were invited to participate in the third wave of a 10-year longitudinal study (Project EAT-III: 2008-2009) examining factors associated with weight-related behaviors. Participants were mailed invitation letters providing the web address and a unique password for completing the survey. Nonresponders were mailed three reminder invitations; the third mailing included the paper form, and all other mailings included a postage-paid card for requesting the paper form. Most completed surveys (82.1% of n=2,287) were returned by respondents within the first four months of fielding prior to the mailing which included the paper form. Nearly all of these early responders (92.6% of n=1,878) and 86.5% of the full respondent sample (n=1,979 of 2,287) completed the web form. Response to the web versus mailed paper form of the survey was associated with age >25 years, higher socioeconomic status, current employment, student status, and having no children. The combination of web and mailed survey modes is an effective strategy for conducting data collection in demographically diverse, young adult populations.