Novel Techniques for the Assessment of Physical Activity in Children

描述(申请人提供)：在过去的几年里，使用加速度计测量儿童的体力活动有了很大的增加。加速计通常佩戴在腰部，它们有内部时钟和大容量的存储容量，非常适合作为一种非侵入性的客观方法来跟踪几天到几周的身体活动模式。通常，通过使用与能量消耗有关的计数的单线性回归方程，将加速度计数据(计数)转换为在轻、中和剧烈体力活动中花费的能量消耗或时间的估计。此外，为成年人开发的公式不适用于儿童，因为计数和能量消耗之间的关系受到年龄和体重等因素的影响。最近，该研究小组的成员开发了一个用于成年人的2-回归模型，该模型根据加速度计计数的变异性，将散步和慢跑与间歇性生活方式活动区分开来。2-回归模型在估计成年人在轻度、中度和剧烈体力活动中的能量消耗和时间的准确性和精确度方面提供了显著的改进。这项提案将解决将用于分析成人加速度计数据的更先进方法扩展到儿童的需求。这项研究的具体目的是：1)在8-9岁的儿童(n=120)中，使用从久坐行为到剧烈体育活动的18项结构化活动的10分钟活动，建立一个2-回归模型；以及2)在8-9岁的单独样本(n=72)中，使用7项每项10分钟的活动和2小时的自由生活活动来验证新的2-回归模型。该项目的总体目标是开发一个2-回归模型，该模型将提高8-9岁儿童在轻度、中度和剧烈体力活动中所花费的能量消耗和时间的估计的准确性和精确度。此外，在2-回归模型的开发和验证过程中，我们将包括同等数量的正常体重儿童(BMI和lt；85%，具体年龄和性别)和超重和肥胖儿童(BMI和gt；85%，年龄和性别具体)。这将有助于进一步了解体重和身体成分等因素如何影响加速度计计数和能量消耗之间的关系。这项研究中开发的方法随后将用于未来的研究，考察具有广泛体型和种族/民族的更大年龄组(例如，6-18岁)。与公共卫生相关：在过去的20年里，学龄儿童中的肥胖人数增加了一倍多，这是一个严重的公共卫生问题。体力活动在预防和治疗肥胖和其他代谢紊乱方面发挥着重要作用。本研究将为儿童体力活动评估提供改进的方法。

DESCRIPTION (provided by applicant): The use of accelerometers for the measurement of physical activity in children has increased substantially over the last several years. Accelerometers are typically worn on the waist and they have internal clocks and large memory capacities making them well suited as a non-invasive objective method of tracking physical activity patterns for days to weeks. Typically, accelerometer data (counts) are converted to estimates of energy expenditure or time spent in light, moderate and vigorous physical activity, by using single linear regression equations relating counts to energy expenditure. In addition, the equations developed for adults are not applicable to children since the relationship between counts and energy expenditure is affected by factors such as age and body mass. Recently members of this research group have developed a 2-regression model, for use in adults, which distinguishes walking and jogging from intermittent lifestyle activities based on the variability in the accelerometer counts. The 2-regression model provided a significant improvement in the accuracy and precision of estimating energy expenditure and time spent in light, moderate, and vigorous physical activity, in adults. This proposal will address the needs of extending the more advanced methods used to analyze accelerometer data in adults to children. The specific aims of the study are to: 1) Develop a 2- regression model in children 8-9 years of age (n=120) using 10 minute bouts of 18 structured activities that will range from sedentary behaviors to vigorous physical activities; and 2) Validate the new 2-regression model in a separate sample of children 8-9 years of age (n=72) using seven activities performed for 10 minutes each and 2 hours of free-living activity. The overall goal of the project is to develop a 2-regression model that will improve the accuracy and precision for estimating energy expenditure and time spent in light, moderate, and vigorous physical activity in children 8-9 years of age. In addition, during the development and validation of the 2-regression model, we will include equal numbers of normal weight children (BMI < 85th percentile, age and sex specific) and overweight and obese children (BMI > 85th percentile, age and sex specific). This will allow for further understanding about how factors such as weight and body composition affect the relationship between accelerometer counts and energy expenditure. The methodologies developed in this study will then be used for future research examining a larger age group (e.g., 6-18 years of age) with a wide range of body sizes and race/ethnicities. PUBLIC HEALTH RELEVANCE: Over the last 20 years obesity has more than doubled in school-aged children and is a serious public health concern. Physical activity plays an important role in the prevention and treatment of obesity and other metabolic disorders. This study will provide improved methods for physical activity assessment in children.