Post-Graduate Program in Epidemiology, Federal University of Pelotas, Pelotas, Brazil.
Int J Epidemiol. 2011 Jun;40(3):685-98. doi: 10.1093/ije/dyq272. Epub 2011 Jan 18.
It is presumed that physical activity (PA) level declines during the lifespan, particularly in adolescence. However, currently, there is no study that quantifies these changes and pools results for a common interpretation. Therefore, the purpose was to systematically review the international literature regarding PA change during adolescence, and to quantify that change according to a series of study variables, exploring gender-and-age differences.
An electronic search was conducted in the Medline/PubMed and Web of Science databases. Longitudinal studies with, at least, two PA measures throughout adolescence (10-19 years old) or the first PA measure during childhood and the second one during adolescence were selected. From each article, study project name, country, year of the first data collection, sample size, baseline age, follow-up duration, characteristics of the instrument (type, recall time, PA intensity and PA domain), unit of PA measure and report of statistical significance were collected.
Overall, 26 studies matched the inclusion criteria. Most were carried out in the USA, assessed PA by questionnaire, and found a decline in PA levels during the adolescence. On average, the mean percentage PA change per year, across all studies, was -7.0 (95% confidence interval: -8.8 to -5.2), ranging from -18.8 to 7.8. The decline was significant according to most sub-groups of variables analysed. Although earlier studies revealed a higher PA decline in boys, the decline has been greater in girls in more recent studies (commenced after 1997). Moreover, although the decline among girls was higher in younger ages at baseline (9-12 years), it was higher in older ages (13-16 years) among boys.
The decline of PA during adolescence is a consistent finding in the literature. Differences between boys and girls were observed and should be explored in future studies. Interventions that attempt to attenuate the PA decline, even without an increase in PA levels, could be considered as effective.
据推测，体力活动（PA）水平会随着寿命的增长而下降，尤其是在青春期。然而，目前尚无研究对这些变化进行量化并汇总结果以进行统一解释。因此，本研究的目的是系统地回顾国际上关于青春期 PA 变化的文献，并根据一系列研究变量对这些变化进行量化，同时探讨性别和年龄差异。
在 Medline/PubMed 和 Web of Science 数据库中进行电子检索。选择了至少有两次在青春期（10-19 岁）期间进行 PA 测量或在儿童期进行第一次 PA 测量，在青春期进行第二次 PA 测量的纵向研究。从每篇文章中，收集研究项目名称、国家、第一次数据收集的年份、样本量、基线年龄、随访时间、仪器特征（类型、回忆时间、PA 强度和 PA 领域）、PA 测量单位和统计显著性报告。
总体而言，有 26 项研究符合纳入标准。这些研究大多数在美国进行，使用问卷评估 PA，并发现 PA 水平在青春期下降。平均而言，所有研究中每年 PA 变化的平均值为-7.0%（95%置信区间：-8.8%至-5.2%），范围从-18.8%到 7.8%。根据分析的大多数子组变量，下降具有统计学意义。尽管早期的研究表明男孩的 PA 下降幅度较大，但在最近的研究中（始于 1997 年之后），女孩的下降幅度更大。此外，尽管女孩在基线年龄较小（9-12 岁）时下降幅度较高，但男孩在年龄较大（13-16 岁）时下降幅度更高。
青春期 PA 下降是文献中的一致发现。观察到了男孩和女孩之间的差异，未来的研究应该进一步探讨这些差异。即使 PA 水平没有增加，尝试减轻 PA 下降的干预措施也可以被认为是有效的。
