Cohen Deborah A, Ashwood J Scott, Scott Molly M, Overton Adrian, Evenson Kelly R, Staten Lisa K, Porter Dwayne, McKenzie Thomas L, Catellier Diane
RAND Corporation, 1776 Main St, Santa Monica, CA 90407-2138, USA.
Pediatrics. 2006 Nov;118(5):e1381-9. doi: 10.1542/peds.2006-1226.
Physical activity may be constrained or facilitated by local environments. The availability of neighborhood facilities for physical activity may be particularly relevant for youth, who are unable to drive and whose activity is often limited to the immediate distance they are able to walk or bicycle. Several studies have shown that proximity to recreational facilities and parks is one of the most important predictors of physical activity. Because the United States already has an extensive infrastructure of parks, with 70% of adults indicating that they live within walking distance of a park or playground, parks may be a potential venue for increasing physical activity. This might be particularly important for adolescent girls, whose physical activity levels decline substantially as they go through puberty. The goal of this study was to examine the association between park proximity, park type, and park features and physical activity in adolescent girls.
This was a cross-sectional study using baseline data from the Trial of Activity for Adolescent Girls. It included 1556 grade 6 girls who were randomly selected from 6 middle schools in each of the following 6 field site areas: Washington, DC, and Baltimore, Maryland; Columbia, South Carolina; Minneapolis, Minnesota; New Orleans, Louisiana; Tucson, Arizona; and San Diego, California. Girls wore accelerometers for 6 days to measure metabolic equivalent-weighted moderate-to-vigorous physical activity, a measure accounting for the volume and intensity of activity. Metabolic equivalent-weighted moderate-to-vigorous physical activity was calculated for the hours outside of school time using 2 different cutpoints, activity levels > or = 3.0 metabolic equivalents and > or = 4.6 metabolic equivalents, the latter indicating activity at the intensity of a brisk walk or higher. We mapped all of the parks within 1 mile of each girl's home. Trained staff used a checklist to document the presence of facilities and amenities at each park, including passive amenities, such as drinking fountains, restrooms, and areas with shade, as well as active amenities like basketball courts, multipurpose fields, playgrounds, and tennis courts.
Mean nonschool metabolic equivalent-weighted moderate/vigorous physical activity, using the 4.6 metabolic equivalent cutoff, was 611.1 minutes (range: 49.7-4718.6 metabolic equivalent minutes per 6 days) and 1704.8 metabolic equivalent minutes per 6 days (range: 276.2-5792.6 metabolic equivalent minutes per 6 days) when using the 3.0 metabolic equivalent cutpoint. Many girls had multiple parks within a 1-mile radius of their homes: 57% had > or = 1 type of park, the majority being neighborhood or community parks; 42% had between 1 and 3 parks, 37% had > or = 4 parks, and 14% had > or = 8 parks. The type, number, and specific parks features were associated with girls' nonschool metabolic equivalent-weighted moderate/vigorous physical activity. At the 4.6 metabolic equivalent cutpoint, higher levels of nonschool metabolic equivalent-weighted moderate/vigorous physical activity were associated with both neighborhood and community parks (22 metabolic equivalent minutes) and miniparks (40 metabolic equivalent minutes). Each park, regardless of type, in the half-mile around each girl's home was associated with an increase in nonschool metabolic equivalent-weighted moderate/vigorous physical activity by 2.8% or 17.2 nonschool minutes of metabolic equivalent-weighted moderate/vigorous physical activity per 6 days. Beyond a half-mile, each park increased nonschool metabolic equivalent-weighted moderate/vigorous physical activity by 1.1% or 6.7 metabolic equivalent minutes per 6 days. For the average girl with 3.5 parks within a 1-mile radius of home, the presence of parks accounted for 36.5 extra nonschool metabolic equivalent minutes per 6 days, approximately 6% of total nonschool metabolic equivalent-weighted moderate/vigorous physical activity. Using the 3.0 metabolic equivalent cutpoint, this sums to an additional 68 metabolic equivalent minutes of nonschool metabolic equivalent-weighted moderate/vigorous physical activity over 6 days, or 4% of the total. The most common amenities in the parks were playgrounds, multipurpose fields, and picnic areas. Slightly more than one third of girls lived within a half-mile of a park with a basketball court, and > 20% had access to walking paths and tennis courts in their local park. Higher levels of nonschool metabolic equivalent-weighted moderate/vigorous physical activity per 6 days were associated with walking paths (13 metabolic equivalent minutes), running tracks (82 metabolic equivalent minutes), playgrounds (28 metabolic equivalent minutes), and basketball courts (30 metabolic equivalent minutes). Parks with streetlights and floodlights were also associated with an increase of 18 and 22 minutes of nonschool metabolic equivalent-weighted moderate/vigorous physical activity, respectively. With the 3.0 metabolic equivalent cutoff for metabolic equivalent-weighted moderate/vigorous physical activity, additional nonschool metabolic equivalent minutes more than doubled when girls had miniparks (92 metabolic equivalent minutes), natural resource areas (36 metabolic equivalent minutes), walking paths (59 metabolic equivalent minutes), and running tracks (208 metabolic equivalent minutes) within a half-mile of their homes. Skateboard areas and special-use parks were negatively associated with nonschool metabolic equivalent-weighted moderate/vigorous physical activity in adolescent girls.
Adolescent girls who live near more parks, particularly near those with amenities that are conducive to walking and with active features, engage in more nonschool metabolic equivalent-weighted moderate/vigorous physical activity than those with fewer parks. Whether this is because of actual use of the parks or neighborhood choice could not be determined. Although the magnitude of the association between parks and additional minutes of metabolic equivalent-weighted moderate/vigorous physical activity was small for an individual, amounting to an average of 4%-6% of a girl's total nonschool metabolic equivalent-weighted moderate/vigorous physical activity, it is likely to have a large population-level association. Because of the potential population level impact, the use of parks to promote physical activity should be further studied.
身体活动可能会受到当地环境的限制或促进。社区体育活动设施的可及性对于青少年可能尤为重要，因为他们无法开车，其活动范围通常限于能够步行或骑自行车到达的较近距离。多项研究表明，靠近娱乐设施和公园是身体活动最重要的预测因素之一。由于美国已经拥有广泛的公园基础设施，70%的成年人表示他们居住在距离公园或游乐场步行可达的范围内，公园可能是增加身体活动的潜在场所。这对青春期女孩可能尤为重要，因为她们的身体活动水平在青春期会大幅下降。本研究的目的是探讨公园距离、公园类型、公园设施与青春期女孩身体活动之间的关联。
这是一项横断面研究，使用了来自青少年女孩活动试验的基线数据。研究纳入了1556名六年级女孩，她们是从以下6个实地研究区域的每个区域的6所中学中随机选取的：华盛顿特区和马里兰州巴尔的摩市；南卡罗来纳州哥伦比亚市；明尼苏达州明尼阿波利斯市；路易斯安那州新奥尔良市；亚利桑那州图森市；加利福尼亚州圣地亚哥市。女孩们佩戴加速度计6天，以测量代谢当量加权的中度至剧烈身体活动，该指标考虑了活动的量和强度。使用2个不同的切点计算非在校时间的代谢当量加权中度至剧烈身体活动，活动水平≥3.0代谢当量和≥4.6代谢当量，后者表示快走或更高强度的活动。我们绘制了每个女孩家1英里范围内的所有公园。经过培训的工作人员使用清单记录每个公园的设施和便利设施的存在情况，包括被动设施，如饮水机、洗手间和有遮阳的区域，以及主动设施，如篮球场、多功能场地、游乐场和网球场。
使用4.6代谢当量切点时，非在校时间的平均代谢当量加权中度/剧烈身体活动为611.1分钟（范围：每6天49.7 - 4718.6代谢当量分钟），使用3.0代谢当量切点时为每6天1704.8代谢当量分钟（范围：每6天276.2 - 5792.6代谢当量分钟）。许多女孩家1英里半径范围内有多个公园：57%的女孩有≥1种类型的公园，大多数是社区或邻里公园；42%的女孩有1 - 3个公园，37%的女孩有≥4个公园，14%的女孩有≥8个公园。公园的类型、数量和特定设施与女孩的非在校代谢当量加权中度/剧烈身体活动相关。在4.6代谢当量切点时，较高水平的非在校代谢当量加权中度/剧烈身体活动与邻里公园（22代谢当量分钟）、社区公园（22代谢当量分钟）和小型公园（40代谢当量分钟）相关。每个女孩家半英里范围内的每个公园，无论类型如何，都与非在校代谢当量加权中度/剧烈身体活动增加2.8%或每6天增加17.2分钟的非在校代谢当量加权中度/剧烈身体活动相关。在半英里之外，每个公园使非在校代谢当量加权中度/剧烈身体活动每6天增加1.1%或6.7代谢当量分钟。对于家1英里半径范围内平均有3.5个公园的女孩，公园的存在使每6天额外增加36.5分钟的非在校代谢当量，约占非在校代谢当量加权中度/剧烈身体活动总量的6%。使用3.0代谢当量切点时，这相当于6天内额外增加68分钟的非在校代谢当量加权中度/剧烈身体活动，占总量的4%。公园中最常见的便利设施是游乐场、多功能场地和野餐区。略多于三分之一的女孩居住在距离有篮球场的公园半英里范围内，超过20%的女孩可以使用当地公园的步行道和网球场。每6天较高水平的非在校代谢当量加权中度/剧烈身体活动与步行道（13代谢当量分钟）、跑道（82代谢当量分钟）、游乐场（28代谢当量分钟）和篮球场（30代谢当量分钟）相关。有路灯和泛光灯的公园也分别与非在校代谢当量加权中度/剧烈身体活动增加18分钟和22分钟相关。对于代谢当量加权中度/剧烈身体活动使用3.0代谢当量切点时，当女孩家半英里范围内有小型公园（92代谢当量分钟）、自然资源区域（36代谢当量分钟）、步行道（59代谢当量分钟）和跑道（208代谢当量分钟）时，额外的非在校代谢当量分钟增加了一倍多。滑板区域和特殊用途公园与青春期女孩的非在校代谢当量加权中度/剧烈身体活动呈负相关。
居住在公园较多附近的青春期女孩，特别是居住在那些有有利于步行的设施和主动设施的公园附近的女孩，比公园较少的女孩进行更多的非在校代谢当量加权中度/剧烈身体活动。这是因为实际使用公园还是邻里选择尚无法确定。尽管公园与额外的代谢当量加权中度/剧烈身体活动分钟数之间的关联程度对于个体来说较小，平均占女孩非在校代谢当量加权中度/剧烈身体活动总量的4% - 6%，但这可能在人群层面有较大关联。由于潜在的人群层面影响，应进一步研究利用公园促进身体活动的情况。
