摘要：Objectives . We examined associations between neighborhood demographic characteristics and the availability of commercial physical activity–related outlets by zip code across the United States. Methods . Multivariate analyses were conducted to assess the availability of 4 types of outlets: (1) physical fitness facilities, (2) membership sports and recreation clubs, (3) dance facilities, and (4) public golf courses. Commercial outlet data were linked by zip code to US Census Bureau population and socioeconomic data. Results . Results showed that commercial physical activity–related facilities were less likely to be present in lower-income neighborhoods and in neighborhoods with higher proportions of African American residents, residents with His-panic ethnicity, and residents of other racial minority backgrounds. In addition, these neighborhoods had fewer such facilities available. Conclusions . Lack of availability of facilities that enable and promote physical activity may, in part, underpin the lower levels of activity observed among populations of low socioeconomic status and minority backgrounds. The positive health benefits associated with regular physical activity include reduced risks of coronary heart disease, diabetes, colon cancer, hip fractures, high blood pressure, and obesity. 1 , 2 Despite such evidence, recent research has shown that more than 50% of adults do not engage in enough physical activity to meet public health recommendations and that 26% report no leisure-time physical activity. 3 Also, a significant proportion of American youths do not participate in sufficient vigorous or moderate exercise. According to data from the 2003 Youth Risk Behavior Survey, 33.4% of high-school students do not engage in either sufficient (at least 20 minutes on 3 or more of the past 7 days) vigorous physical activity or sufficient (at least 30 minutes on 5 or more of the past 7 days) moderate physical activity. 4 Patterns of physical inactivity are not equivalent according to race, ethnicity, or socioeconomic status (SES). Included among the adult populations most at risk for leisure-time inactivity are those at low levels of income and education, those living in poverty, those who are members of racial/ethnic minority groups, and those with disabilities. 1 , 5 , 6 Among youths, data also reveal significant race/ethnicity-specific differences in prevalence rates of insufficient physical activity (41.2% among Black youths, 36.5% among Hispanic youths, and 31.9% among White youths). 4 In the Youth Media Campaign Longitudinal Survey focusing on children aged 9 to 13 years, for example, rates of participation in organized sports differed substantially according to race and parental income and education levels. 7 Also, drawing on the National Longitudinal Study of Adolescent Health, Gordon-Larsen et al. found that physical activity and inactivity patterns varied significantly according to ethnicity among youths in grades 7 through 12. 8 In an attempt to explain determinants of physical activity behavior, recent models have broadened beyond demographic, psychological, and social explanatory variables to include the importance of environmental factors. 9 – 11 Ecological models are based on the notions that physical activity takes place in specific physical environments designed for or conducive to activity (e.g., sports fields, gyms, health clubs, bicycle trails) and that these settings are likely to influence types and amounts of activity. 9 Several studies involving the use of self-reported perceived measures have shown that there is a positive correlation between the availability of physical activity–related facilities and settings and various exercise behaviors. 12 – 17 A limited body of research has examined associations between the availability of facilities and settings, as assessed through objective (rather than self-reported) measures, and physical activity behavior. Sallis et al. 18 found that, after control for individual characteristics, closer proximity and higher density of exercise facilities were significantly associated with increased frequency of exercise. An environmental intervention aimed at reducing barriers to physical activity (including increasing the availability of physical activity–related equipment and facilities) revealed statistically significant positive changes in overall fitness measures within the intervention community. 19 Recent research has begun to assess the extent to which the availability of physical activity–related facilities or settings varies across neighborhoods on the basis of racial/ethnic or SES characteristics. Self-report data suggest that perceived environmental barriers to physical activity vary significantly according to race and SES. The Youth Media Campaign Longitudinal Survey showed that parents of non-Hispanic Black versus White children and parents at relatively lower income and education levels perceived significantly higher activity barriers, including transportation problems, lack of opportunities to participate in physical activity, expense, and concerns about neighborhood safety. 7 Examining the association between SES and perceived opportunities for physical activity (in terms of facilities available, such as playgrounds and parks or gyms close to home) in 56 neighborhoods of a city located in the Pacific Northwest, Duncan found that residents of neighborhoods with lower poverty levels perceived significantly more such opportunities. 20 Another study that assessed perceived neighborhood characteristics and access to physical activity spaces among 1796 adults residing in 6 counties in North Carolina revealed that access to physical activity spaces and trails increased with increasing levels of education and income. 17 To our knowledge, only a few studies have examined differences across neighborhoods according to objective rather than self-reported measures of available physical activity–related opportunities. Estabrooks et al. examined the availability and accessibility of physical activity resources across 32 different census tracts in a small midwestern city according to neighborhood SES. 21 They found, on the basis of a list of 177 physical activity resources (including parks, sports facilities, fitness clubs, community centers, and walking/ bike trails), that low- and medium-SES neighborhoods had significantly fewer resources available than their high-SES counterparts. In terms of accessibility, differences across low-, medium-, and high-SES census tracts were not observed for pay-for-use resources, but low-and medium-SES neighborhoods were found to have significantly fewer no-cost resources. In a recent study, Powell et al. linked census data on race/ethnicity and SES to observational data on public physical activity settings (e.g., sports areas, parks and green spaces, public pools and beaches, bike paths/lanes) collected from 409 communities across the United States in an attempt to assess how availability varies with respect to the socioeconomic and demographic compositions of local populations. 22 Results revealed that communities with higher percentages of African American residents were likely to have fewer available sports areas, parks and green spaces, and public pools and beaches. Also, communities with lower median household incomes, higher poverty rates, and higher percentages of African American and other minority residents were shown to have fewer overall total physical activity–related settings of those assessed. In the present comprehensive, multivariate national study (comprising a population of 280675874 people living in 28050 zip code areas with 52751 available physical activity–related outlets as of the year 2000), we assessed the availability of commercial physical activity–related outlets by zip code across the United States, along with the associations between the availability of such facilities and neighborhood demographic characteristics such as race/ethnicity and SES. We examined both the presence and extent of availability (i.e., number present) of 4 broad types of physical activity–related settings: (1) physical fitness facilities; (2) membership sports and recreation clubs; (3) dance studios, schools, and halls; and (4) public golf courses. These commercial outlet data were linked by zip code to US Census Bureau population and SES data.
