participant signed the informed consent to participate in the study. Seventy-three women participated in the study and were asked to wear the devices for 3 weekdays. Participants were excluded if they had incomplete step data, rode a cycle, used an elliptical machine, or ran on ≥2 of the weekdays. Thus, 13
Brian Tyo, Rebecca Spataro-Kearns and David R. Bassett Jr.
Alberto Flórez-Pregonero, Matthew S. Buman and Barbara E. Ainsworth
category included sitting in a chair or laboratory stool, reclining, and lying down in a supine and/or prone position. Simultaneously, two investigators directly observed a participant’s movement in their free-living environment for six hours per day during two separate days; on a weekday (visit 2) and a
Lennart Raudsepp and Peep Päll
The purpose of this study was to examine the between-day reproducibility of physical activity across 1 week and determine the stability of physical activity over 2 years. Forty-two children (19 boys, 23 girls) aged 8–9 years at the beginning of the study were followed across 1 week and over a 2-year period. Physical activity was assessed by Caltrac accelerometer. Reproducibility and stability of physical activity was analyzed using Spearman correlations. The results revealed significant Spearman rank order correlations between weekdays (r = 0.64 to 0.79) and weekend days (r = 0.53 to 0.67). Spearman rank order correlations between weekdays and weekend days during two monitoring sessions were consistently lower, ranging from 0.34 to 0.57. It was concluded that the between-day reproducibility of accelerometer monitoring was higher between similar days of the week (weekdays or weekend days). Shortterm stability of physical activity during late childhood was moderate.
Helen Gilbey and Malcolm Gilbey
Physical activity patterns of Singapore school children aged 9–10 years were assessed by continuous heart rate monitoring. Fifty boys and 64 girls were monitored for three 14-hour periods during normal school days. In addition, 43 boys and 53 girls were monitored for 14 hours on a Saturday. Only 13 children (11.4%) experienced a daily 10-min period of continuous activity at a heart rate ≥140 bpm. Twenty percent of the boys and more than 50% of the girls never achieved a single 10-minute period ≥140 bpm. Boys achieved more periods of moderately intense activity (p < .01) than girls on weekdays. Lean girls were more active (p < .05) than the obese girls during weekdays. No differences were detected between activity levels on weekdays or on Saturday. The results indicate that Singapore school children in general rarely experience the quantity or quality of physical activity needed for maintenance and development of cardiovascular health and cardiopulmonary fitness.
Jorge Mota, José Ribeiro, Maria Paula Santos and Helena Gomes
This study aimed to examine the relationship between obesity status (body mass index: BMI) and physical and sedentary activities in adolescents. The sample comprised 230 girls and 220 boys (14.6 years old, SD = 1.6). Physical Activity (PA) was assessed by a questionnaire. Sedentary behaviors, such as TV viewing, computer use, and commuting to and from school were analyzed. Participants were categorized as nonobese or overweight/obese according to age-adapted BMI. No significant differences were found in relation to PA characteristics or in TV watching on weekdays vs. weekends. Nonobese participants spent significantly less time using computers on weekends (p = .04) and weekdays (p = .025) than their overweight/obese counterparts. Logistic regression analysis showed that those who used computers on weekdays more than 4 hrs per day were likely (odds ratio: 5.79; p < .003) to be overweight or obese. This study identified a relationship between computer use, but not physical activity or TV viewing, and weight status among Portuguese adolescents.
The purpose of this study was to examine whether physical activity (PA) and sedentary behavior were related to weight status in Korean adolescents. A total of 72,399 students in Grades 7–12 participated in the 5th Korea Youth Risk Behavior Web-Based Survey (KYRBWS-V) project in 2009. Body mass index, PA, and sedentary behavior were assessed by the KYRBWS-V. The study results show that boys had higher PA and less sedentary behavior than did girls (p < .01). The amounts of vigorous PA (p < .001), moderate PA (p < .001), moderate PA for at least 60 min (p < .001), exercise for muscle strength (p < .001), walking on a weekday (p < .001), and walking on a weekend (p = .012) were less in boys who were more obese than the other boys. The time spent sitting on a weekday (p < .001) and weekend (p < .001) was higher in more obese individuals in boys. Exercise for muscle strength (p = .011) was less in girls who were more obese. Time spent sitting on a weekday (p = .005) and weekend (p < .001) was higher in more obese individuals in girls. However, vigorous PA (p < .001), moderate PA (p < .001), moderate PA for at least 60 min (p = .003), and walking on a weekday (p < .001) were higher for the more obese girls. PA and sedentary behavior could be independent factors that reduce or prevent obesity in Korean adolescents.
Gerson Luis de Moraes Ferrari, Timoteo Leandro Araujo, Luis Oliveira, Victor Matsudo, Emily Mire, Tiago V. Barreira, Catrine Tudor-Locke and Peter T. Katzmarzyk
Studies have found an association between television (TV) viewing and physical activity levels. The purpose of this study was to examine the association between TV viewing and physical activity in 10-year-old Brazilian children.
The sample consisted of 485 children. Self-reported TV viewing on weekdays and weekends was assessed by questionnaire. An Actigraph GT3X+ accelerometer was used to monitor the range of physical activity intensities (including moderate-to-vigorous physical activity; MVPA), sedentary behavior (SB) and steps/day over 7 days.
Daily MVPA was highest among children viewing TV <1 hour/day (69 min) compared with children viewing 1 to 2 hours/day (61 min), 3 to 4 hours/day (55 min) and ≥ 5 hours/day (59 min) on weekdays (P = .0015). Differences in MVPA were not observed across TV categories on weekends. The prevalence of reaching 60 min/day of MVPA and 12,000 steps/day on weekdays was significantly greater in children viewing ≤ 2 hours/day (51.7% and 23.5%, respectively) compared with those viewing > 2 hours/day (38.6%, P = .0058; and 15.1%, P = .0291, respectively). There was no difference in SB across TV viewing categories.
Time spent in MVPA and the frequency of meeting MVPA guidelines were significantly higher among children viewing ≤ 2 hours/day of TV on weekdays compared with those viewing more.
Cheryl L. Addy, Jennifer L. Trilk, Marsha Dowda, Won Byun and Russell R. Pate
The purpose of this study was to determine the minimum number of days of accelerometry required to estimate accurately MVPA and total PA in 3- to 5-year-old children. The study examined these metrics for all days, weekdays, and in-school activities. Study participants were 204 children attending 22 preschools who wore accelerometers for at least 6 hr per day for up to 12 days during most waking hours. The primary analysis considered the intraclass correlation coefficient (ICC) for each metric to estimate the number of days required to attain a specified reliability. The ICC estimates are 0.81 for MVPA-all days, 0.78 for total PA-all days, 0.83 for MVPA weekdays, 0.80 for total PA-weekdays, 0.81 for in-school MVPA, and 0.84 for in-school total PA. We recommend a full seven days of measurement whenever possible, but researchers can achieve acceptable reliability with fewer days, as indicated by the Spearman-Brown prophecy: 3–4 days for any weekday measure and 5–6 days for the all-days measures.
Jamie Lye Ching Ting, Swarup Mukherjee and Michael Chia Yong Hwa
Adolescents require at least 60 minutes of daily moderate to vigorous intensity physical activity (PA) for optimum health benefits. Reduced active and increased sedentary time can adversely affect health independently. This study investigated the sedentary behavior and physical activity patterns of Singaporean adolescents.
233 adolescents aged 13 to 15 years participated in the study. Accelerometry was used to assess the daily PA patterns for 3 weekdays and 2 weekend days consecutively. Height, weight, BMI, waist circumference and waist-hip ratio were determined as surrogate measures of health.
None of the participants achieved the recommended 60 minutes of daily moderate-to-vigorous physical activity (MVPA) on all 5 days. Significantly more time was spent engaging in sedentary activity compared with MVPA on both weekdays and weekends. MVPA and sedentary time were positively associated on weekdays after controlling for gender (P < .001). Weekday MVPA was positively associated with waist circumference (P < .001) and waist-hip ratio (P < .001).
Singaporean adolescents fall substantially short of meeting the daily PA recommendations. Separate strategies to promote PA may be necessary for adolescents of differing weight status and gender. Pragmatic rather than idealistic targets to promote PA need to be set based on population-specific baseline data.
Trish Gorely, Stuart Biddle, Simon Marshall, Noel Cameron and Louise Cassey
The purpose of this research was to investigate the relationship between distance to school and levels of physical activity and sedentary behavior in UK adolescents. Participants were 1385 adolescents (boys n = 531; mean age 14.7 years). Boys living within two miles of school and girls living within 5 miles of school were more likely to report high levels (≥60 min per day) of weekday leisure time physical activity. Differences in weekday leisure time physical activity were accounted for by active travel time. There were no differences in sedentary behavior time by distance to school. Journeys, whether active or motorized, most often took place with friends. Further research should investigate wider physical and social environmental influences on active travel.