Jennifer R. O'Neill

The Evolving Definition of ''Sedentary''

Studies that did not directly measure sedentary behavior often have been used to draw conclusions about the health effects of sedentariness. Future claims about the effects of sedentary, light, and moderate-to-vigorous activities on health outcomes should be supported by data from studies in which all levels of physical activity are differentiated clearly and measured independently.

Motor Skill Performance and Physical Activity in Preschool Children

Children with better‐developed motor skills may find it easier to be active and engage in more physical activity (PA) than those with less‐developed motor skills. The purpose of this study was to examine the relationship between motor skill performance and PA in preschool children. Participants were 80 three‐ and 118 four‐year‐old children. The Childrens Activity and Movement in Preschool Study (CHAMPS) Motor Skill Protocol was used to assess process characteristics of six locomotor and six object control skills; scores were categorized as locomotor, object control, and total. The actigraph accelerometer was used to measure PA; data were expressed as percent of time spent in sedentary, light, moderate‐to‐vigorous PA (MVPA), and vigorous PA (VPA). Children in the highest tertile for total score spent significantly more time in MVPA (13.4% vs. 12.8% vs. 11.4%) and VPA (5% vs. 4.6% vs. 3.8%) than children in middle and lowest tertiles. Children in the highest tertile of locomotor scores spent significantly less time in sedentary activity than children in other tertiles and significantly more time in MVPA (13.4% vs. 11.6%) and VPA (4.9% vs. 3.8%) than children in the lowest tertile. There were no differences among tertiles for object control scores. Children with poorer motor skill performance were less active than children with better‐developed motor skills. This relationship between motor skill performance and PA could be important to the health of children, particularly in obesity prevention. Clinicians should work with parents to monitor motor skills and to encourage children to engage in activities that promote motor skill performance.

Policies and Characteristics of the Preschool Environment and Physical Activity of Young Children

OBJECTIVE. The purpose of this study was to examine policies and characteristics of preschools and the extent to which they influence the physical activity of 3- to 5-year-old children during the preschool day. METHODS. A total of 299 children from 20 preschools wore accelerometers for an average of 8.1 hours/day (SD: 1.5 hours/day), for 5.5 days (SD: 2.1 days). A researcher completed the Early Childhood Environment Rating Scale-Revised for each preschool to assess quality. Classrooms and playgrounds were measured, and the preschool director was interviewed about physical activity policies. For each policy or characteristic, preschools were divided into 2 groups on the basis of whether the characteristic/policy was presumed to promote or not promote physical activity. RESULTS. Children spent fewer minutes per hour in sedentary activity and more minutes per hour in moderate/vigorous physical activity in preschools that had higher quality scores, less fixed playground equipment, more portable playground equipment, lower use of electronic media, and larger playgrounds. Five preschools had all 5 of these characteristics, and children in those preschools had significantly more moderate/vigorous physical activity minutes per hour and fewer sedentary minutes per hour compared with children in the other preschools. CONCLUSION. Children in the top 5 physical activity–promoting preschools accumulated >60 minutes of moderate/vigorous physical activity per day, compared with the children in the other preschools, who accumulated <60 minutes of moderate/vigorous physical activity per day.

Measurement of Physical Activity in Preschool Children

PURPOSE To provide an overview of the methods that have been developed for measurement of physical activity in children of preschool age. Emphasis will be given to direct observation and accelerometry, but pedometry, HR monitoring, and proxy reports will be reviewed as well. METHOD Research articles detailing the measurement properties of direct observational systems, accelerometry, pedometry, HR monitoring, and proxy reporting specifically in children of preschool age were selected and reviewed. RESULTS Systems for direct observation of physical activity and accelerometry are valid and reliable measures of physical activity in young children. Direct observation, which can provide information on type and context of physical activity, is an excellent complement to accelerometry, which provides detailed information on the intensity and duration of physical activity but no contextual information. CONCLUSIONS Direct observation systems and accelerometry have become well-established measurements of physical activity in young children as well as older groups. Pedometry and HR monitoring have been shown to be applicable, but these methods have been studied less extensively than direct observation and accelerometry. Proxy reports of physical activity are attractive because of low burden, but they have limited validity.

Prevalence of Compliance with a New Physical Activity Guideline for Preschool-Age Children

BACKGROUND Four expert panels from Australia, Canada, the United Kingdom, and the United States issued physical activity (PA) recommendations for young children that are quite similar. The aim of this study was to determine compliance with the new PA guideline (defined as ≥15 min/hr of total PA) in two independent samples of preschool children. METHODS We conducted a cross-sectional study of children attending preschools in Columbia, South Carolina. A total of 286 children in one sample and 337 children in a second sample participated. The main outcome of interest was total PA (sum of light, moderate, and vigorous intensity activity) measured by accelerometry. Compliance with the PA guideline was determined for both samples. Separately for each sample, mixed logistic models were used to determine whether there were differences in compliance with the PA guideline between groups based on sex, race/ethnicity, parent education, and weight status, controlling for preschool. RESULTS Total PA was 14.5 and 15.2 min/hr in the first and second samples, respectively. The prevalence of meeting the PA guideline was 41.6% and 50.2% in the first and second samples, respectively. In both samples, more males than females met the guideline (53.5% vs. 33.5% and 57.6% vs. 45.9%) in the first and second samples, respectively (p<0.05). CONCLUSIONS Approximately one half of children in two independent samples met the guideline for PA in young children. Policies and practices designed to increase PA among preschool children are needed, given that most children are not meeting this PA guideline.

Descriptive Epidemiology of Dance Participation in Adolescents

Abstract The aims of this study were to describe the prevalence of dance participation in U.S. adolescents and to estimate the contribution of dance to total moderate-to-vigorous physical activity (MVPA). The sample was composed of 3,598 adolescents from the 2003–06 National Health and Nutrition Examination Survey. Youth reported frequency and duration of physical activities performed in the past month. Dance participation prevalence was calculated; among those who reported dance, its contribution to total MVPA was estimated. The prevalence of dance was much higher in girls (34.8%) than boys (8.4%). Girls had a greater contribution of dance to total MVPA (39.3%) than boys (23.0%). Dance is a prevalent form of physical activity among girls, and it accounts for a substantial fraction of their total MVPA.

Moderate‐To‐vigorous physical activity is associated with decreases in body mass index from ages 9 to 15 years

The purpose of this study is to determine whether time spent in objectively measured physical activity is associated with change in body mass index (BMI) from ages 9 to 15.

Use of quantile regression to investigate the longitudinal association between physical activity and body mass index.

To examine associations among age, physical activity (PA), and birth cohort on body mass index (BMI) percentiles in men.

Top 10 research questions related to physical activity in preschool children.

The purpose of this article was to highlight important research needs related to physical activity in 3- to 5-year-old children. We identified research needs in 3 major categories: health effects, patterns of physical activity, and interventions and policies. The top research needs include identifying the health effects of physical activity, the effects of physical activity on the development of healthy weight, the effects of physical activity on learning and behavior, and the health implications of sedentary behavior. Research questions concerning patterns of physical activity include determining the prevalence of 3- to 5-year-olds meeting the current physical activity guidelines; the social and environmental factors that influence physical activity in home, preschool, and community settings; and how physical activity tracks into later childhood, adolescence, and adulthood. Research questions about interventions and policies include identifying the most effective strategies to promote physical activity in home, child care, and community settings and to reach diverse populations of young children, identifying effective intervention implementation and dissemination strategies, and determining the effectiveness of national, state, local, and institutional policies for increasing physical activity. In conclusion, research is needed to establish a full understanding of the health implications of physical activity in 3- to 5-year-old children, to better understand the nature of physical activity behavior in this group, and to learn how to promote physical activity in young children.

Physical Activity in Preschool Children: Comparison between Montessori and Traditional Preschools.

BACKGROUND Little is known about the influence of Montessori methods on childrens physical activity (PA). This cross-sectional study compared PA of children attending Montessori and traditional preschools. METHODS We enrolled 301 children in 9 Montessori and 8 traditional preschools in Columbia, South Carolina. PA was measured by accelerometry on weekdays during preschool (In-School), non-school (Non-School), and all day (All Day). Minutes/hour of light, moderate-to-vigorous (MVPA), and total PA (light + MVPA) were calculated. RESULTS Children attending Montessori preschools accumulated more In-School light (7.7 vs. 6.5 minute/hour), MVPA (7.7 versus 6.5 minute/hour), and total PA (15.4 versus 13.0 minute/hour) than children attending traditional preschools, after adjusting for sex, race/ethnicity, body mass index, parent education and neighborhood poverty index. For Non-School (8.5 versus 6.2 minute/hour) and All Day (8.5 versus 7.6 minute/hour), children in Montessori preschools accumulated more MVPA than children in traditional preschools. In-School PA was higher for children in private Montessori than public Montessori preschools (8.1 versus 7.0 minute/hour; 8.1 versus 6.7 minute/hour; 16.1 versus 13.6 minute/hour, for light, MVPA, and total PA, respectively). CONCLUSIONS Children attending Montessori preschools were more active than children attending traditional preschools. Adopting the Montessori system may be an important strategy for promoting PA in children.