Minutes Of Sedentary Behavior Research Articles

Testing the Effect of a Smartphone App on Hospital Admissions and Sedentary Behavior in Cardiac Rehabilitation Participants: ToDo-CR Randomized Controlled Trial.

People with coronary heart disease are at an increased risk of morbidity and mortality even if they attend cardiac rehabilitation. High sedentary behavior levels potentially contribute to this morbidity. Smartphone apps may be feasible to facilitate sedentary behavior reductions and lead to reduced health care use. We aimed to test the effect of a sedentary behavior change smartphone app (Vire app and ToDo-CR program) as an adjunct to cardiac rehabilitation on hospital admissions and emergency department (ED) presentations over 12 months. A multicenter, randomized controlled trial was conducted with 120 participants recruited from 3 cardiac rehabilitation programs. Participants were randomized 1:1 to cardiac rehabilitation plus the fully automated 6-month Vire app and ToDo-CR program (intervention) or usual care (control). The primary outcome was nonelective hospital admissions and ED presentations over 12 months. Secondary outcomes including accelerometer-measured sedentary behavior, BMI, waist circumference, and quality of life were recorded at baseline and 6 and 12 months. Logistic regression models were used to analyze the primary outcome, and linear mixed-effects models were used to analyze secondary outcomes. Data on intervention and hospital admission costs were collected, and the incremental cost-effectiveness ratios (ICERs) were calculated. Participants were, on average, aged 62 (SD 10) years, and the majority were male (93/120, 77.5%). The intervention group were more likely to experience all-cause (odds ratio [OR] 1.54, 95% CI 0.58-4.10; P=.39) and cardiac-related (OR 3.26, 95% CI 0.84-12.55; P=.09) hospital admissions and ED presentations (OR 2.07, 95% CI 0.89-4.77; P=.09) than the control group. Despite this, cardiac-related hospital admission costs were lower in the intervention group over 12 months (Aus $252.40 vs Aus $859.38; P=.24; a currency exchange rate of Aus $1=US $0.69 is applicable). There were no significant between-group differences in sedentary behavior minutes per day over 12 months, although the intervention group completed 22 minutes less than the control group (95% CI -22.80 to 66.69; P=.33; Cohen d=0.21). The intervention group had a lower BMI (β=1.62; P=.05), waist circumference (β=5.81; P=.01), waist-to-hip ratio (β=.03, P=.03), and quality of life (β=3.30; P=.05) than the control group. The intervention was more effective but more costly in reducing sedentary behavior (ICER Aus $351.77) and anxiety (ICER Aus $10,987.71) at 12 months. The intervention was also more effective yet costly in increasing quality of life (ICER Aus $93,395.50) at 12 months. The Vire app and ToDo-CR program was not an outcome-effective or cost-effective solution to reduce all-cause hospital admissions or ED presentations in cardiac rehabilitation compared with usual care. Smartphone apps that target sedentary behavior alone may not be an effective solution for cardiac rehabilitation participants to reduce hospital admissions and sedentary behavior. Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12619001223123; https://australianclinicaltrials.gov.au/anzctr/trial/ACTRN12619001223123. RR2-10.1136/bmjopen-2020-040479.

Long-term effects of the COVID-19 pandemic on children's physical activity and sedentary behavior.

During the early months of the COVID-19 pandemic, decreases in physical activity (PA) and increases in sedentary behavior (SB) were reported among children in the United States (U.S.). This follow-up analysis examines 13-month effects of the COVID-19 pandemic on children's PA and SB one year into the pandemic. Parents of 5-13-year-old children in the U.S. (N=71) reported on their child's PA and SB during the early COVID-19 period (April-May 2020) and again 12-14months later (June-July 2021). Paired t-tests showed significant within-subject reductions in SB minutes per day (M diff=-86.20, t=3.26, p<0.01) but no changes in PA minutes per day. Separate mixed-model repeated-measures analysis of covariance procedures found that within-subject changes in PA and SB did not differ by child sex or age. As COVID-19 restrictions lessened, there were more opportunities for children to reduce SB, but there were still barriers to engage in PA.

Exploring the Effects of Perceived Stress on the Within-Person Relationships Between Daily Activity Levels and Sleep in Women: An Ecological Momentary Assessment Study.

Many studies show positive bidirectional associations between physical activity (PA) and sleep at the between-person level. There is an increased interest in investigating these associations at the within-person level. Few studies examined the effects of time-varying moderators on the within-person bidirectional associations between PA and sleep. This study aimed to examine the bidirectional within-person day-level associations between activity levels and self-reported sleep duration and explore the moderating effects of perceived stress on these day-level associations. Data from 158 women that included 7-day free-living monitoring over 4 measurement periods was analyzed using multilevel modeling to explore the moderating effects of daily stress on the bidirectional, within-person associations between activity levels and self-reported sleep duration. Moderate-to-vigorous PA (MVPA) and sedentary behavior (SB) were estimated from a waist-worn accelerometer. Self-reported sleep duration and perceived stress were collected by ecological momentary assessment. No significant within-person associations between MVPA minutes and self-reported sleep duration were found in either direction. However, engaging in more MVPA than one's usual level was associated with longer sleep later that night when perceived stress was higher than usual (p = .04). Bidirectional negative within-person association between SB minutes and self-reported sleep duration was found (ps < .01). The negative association between SB and sleep duration later that night was stronger when perceived stress was lower than usual (p = .01). Daily stress played an important role in the day-to-day associations between activity levels and sleep.

Physical activity, sedentary behaviors and all-cause mortality in patients with heart failure: Findings from the NHANES 2007-2014.

BackgroundLimited data are available examining the effects of both moderate- and vigorous-intensity physical activity (MVPA) and sedentary behavior (SB) on longevity among patients with heart failure (HF). This study examined the associations of MVPA and SB with all-cause mortality in HF patients using a nationally representative survey data.MethodsNational Health and Nutrition Examination Survey data (2007–2014) were used. 711 adults with self-reported congestive HF, linked to 2015 mortality data were analyzed. Self-reported MVPA and SB minutes were used to create the three MVPA [No-MVPA, insufficient (I-MVPA; <150 min/wk), and sufficient (S-MVPA; ≥150 min/wk)] and two SB (<8 and ≥8 hrs/d) groups. Cox proportional hazard models were constructed to test the associations of MVPA and SB with all-cause mortality.Results119 deaths occurred over an average of 4.9 years of follow-up. Lower MVPA and higher SB were independently associated with poor survival (P < .001). Joint and stratified analyses showed that the protective effect of MVPA was most pronounced among patients with SB<8 hrs/d. There was no difference in the mortality risk by SB levels within I-MVPA and S-MVPA groups; however, in the No-MVPA group, those with SB≥8 hrs/d had a greater risk of mortality compared to those with <8 hrs/d (Hazard ratio = 1.60).ConclusionIn this HF cohort, MVPA and SB were independently and jointly associated with all-cause mortality. The beneficial effect of MVPA is attenuated by excessive SB; however, engaging in some amount of MVPA may provide a protective effect and attenuates the detrimental effects associated with excessive SB.

Abstract MP26: Replacing Sedentary Behavior Time With Various Daily-life Physical Activities And Structured Exercises, Recommended Physical Activity, And Incident Coronary Heart Disease

Introduction: While excessive sedentary behavior time has been associated with cardiovascular diseases, it is largely unknown to what extend substituting sedentary behaviors with various physical activities may offset the risk of coronary heart disease (CHD). Hypothesis: We hypothesize that reallocating time from sedentary behavior to various daily-life physical activities and structured exercises might be associated with lower risk of CHD. We particularly examined such reallocations according to whether or not the participants meet the recommended physical activity level. Method: A total of 468,960 UK Biobank participants free of CHD were included. Sedentary behavior time was quantified by summing up the time spent on television watching, computer use (not at work), and driving. Physical activities were categorized as daily-life activities (walking for pleasure, light DIY, and heavy DIY) and structured exercise (strenuous sports and other exercises). We used iso-temporal substitution model to estimate the effect of replacing sedentary behavior with each type of physical activity for the same amount of time. Results: During a median follow-up of 11 years, 7,982 incident CHD cases were documented. Sedentary behavior time was significantly associated with a higher risk of CHD, independent of physical activity. In comparison of the extreme categories (≥6 vs. &lt;2 h/d), the HR for CHD was 1.31 (95% CI: 1.18-1.46). Replacing 30 minutes of sedentary behavior per day with an equal time of various physical activities was significantly associated with a 3%-12% risk reduction of CHD. Replacing 1 hour of sedentary behaviors with different types of physical activities was associated with a 6%-23% risk reduction of CHD. Sedentary behavior-to-strenuous sports reallocations showed the largest reduction in CHD risk when replacing sedentary behavior. Moreover, reallocations of sedentary behavior to various physical activities showed particularly greater benefits among those who did not meet the physical activity recommendations. Conclusion: Our study indicates that replacing sedentary behavior time with various daily-life activities or structured exercise was associated with significant reductions in CHD risk.

Gender differences in physical activity and sedentary behavior of Japanese primary school children during school cleaning time, morning recess and lunch recess

BackgroundThe school environment provides crucial opportunities for children to engage in health-promoting physical activity (PA). Japanese children clean their schools and have recess time every school day. The primary aim of the study is to describe the levels of physical activity during school cleaning and recess time while comparing it between genders.MethodsPA and sedentary behavior (SB) of 230 boys and 252 girls aged 6–12 years-old from 14 public primary schools were assessed for 7 consecutive days with a triaxial accelerometer. Minutes of SB, and moderate-to-vigorous PA (MVPA) as a percentage in each of school cleaning time (15 min/day: 58% of the 14 schools or 20 min/day), morning recess time (15 min/day: 6% or 20 min/day) or lunch recess time (15 min/day: 29%, 20 min/day: 47% or 25 min/day) were evaluated. A one-way analysis of variance or Student’s t test was used to examine differences in %PAs and %SB between school cleaning time and morning and lunch recess time, and between genders.ResultsIn a school day, the percentage of total daily MVPA during school cleaning time, morning recess and lunch recess time was 19.4 ± 6.8% (15.2 ± 5.3 min/day) for boys and 16.9 ± 5.8% (10.5 ± 4.3 min/day) for girls. For boys, the proportions of MVPA in morning and lunch recesses and SB during the morning recess were significantly higher than during school cleaning time (p < 0.001). For girls, similar results were obtained and the SB during lunch recess was also higher than during school cleaning time (p < 0.001).ConclusionsThese findings suggest that the total amount of school cleaning time, recess and lunch time likely contribute to daily MVPA but the beneficial effects should be further explored in future intervention studies.

Physical Activity and Sedentary Behaviors of Children in Family Child Care Homes: Are There Opportunities for Improvement?

Many children attend family child care homes (FCCHs), an important setting to influence children's physical activity (PA) and sedentary behavior (SB). This study assessed children's PA and SB while in FCCHs, characteristics of the FCCH PA environment, and relationships between the environment and child PA and SB. Children ages 1.5-4.0 years (n = 495) were recruited from 165 FCCHs in North Carolina. Children's moderate to vigorous PA and SB were measured via accelerometry for 3 days. FCCH PA environments were assessed over 2 days using the Environment and Policy Assessment and Observation for FCCHs. Ten subscores and an overall PA environment score (possible range: 0-30) were calculated; higher scores indicate better quality. Children accumulated 30 (13)minutes of moderate to vigorous PA and 143 (42)minutes of SB in FCCHs daily. FCCHs scored low on the Environment and Policy Assessment and Observation for FCCHs, with an average overall score of 13 (2). FCCHs scored highest on screen time and screen time practices subscores, and lowest on PA education/professional development and PA policy subscores. Although no statistically significant associations were observed, some large Cohen d effect sizes were noted (eg,outdoor playtime subscore and moderate to vigorous PA). This study highlights opportunities to improve FCCHs and increase children's behaviors (eg,providing adequate time and outdoor play spaces).

Accelerometer and GPS Analysis of Trail Use and Associations With Physical Activity.

Concurrent use of accelerometers and global positioning system (GPS) data can be used to quantify physical activity (PA) occurring on trails. This study examined associations of trail use with PA and sedentary behavior (SB) and quantified on trail PA using a combination of accelerometer and GPS data. Adults (N = 142) wore accelerometer and GPS units for 1-4 days. Trail use was defined as a minimum of 2 consecutive minutes occurring on a trail, based on GPS data. We examined associations between trail use and PA and SB. On trail minutes of light-intensity, moderate-intensity, and vigorous-intensity PA, and SB were quantified in 2 ways, using accelerometer counts only and with a combination of GPS speed and accelerometer data. Trail use was positively associated with total PA, moderate-intensity PA, and light-intensity PA (P < .05). On trail vigorous-intensity PA minutes were 346% higher when classified with the combination versus accelerometer only. Light-intensity PA, moderate-intensity PA, and SB minutes were 15%, 91%, and 85% lower with the combination, respectively. Adult trail users accumulated more PA on trail use days than on nontrail use days, indicating the importance of these facilities for supporting regular PA. The combination of GPS and accelerometer data for quantifying on trail activity may be more accurate than accelerometer data alone and is useful for classifying intensity of activities such as bicycling.

Relationship between Outdoor and TV Viewing Time with Children's Movement in Early Care Settings

ABSTRACT Childhood obesity may be prevented by decreasing sedentary behavior (SB) and increasing moderate-to-vigorous physical activity (MVPA) in young children. Outdoor time and TV viewing time may contribute to SB and MVPA. Early childcare and education (ECE) settings are important environments for SB and MVPA. The purpose of this study is to determine the relationship between outdoor and TV viewing time with body mass index (BMI) percentile and movement in children attending ECE. An observational study at ECE centers and classrooms within those centers was conducted. Outdoor and TV viewing times were collected for 2 d using trained research assistants. Height and weight of children were objectively measured. Movement was measured for the entire school day using accelerometry. Dependent variables included BMI percentile, minutes of SB, light physical activity (LPA), MVPA, and steps. Hierarchical models adjusted for confounders and clustering of children in classrooms. In 34 classrooms (202 children), outdoor time was associated with BMI percentile (P &lt; 0.03), SB (P &lt; 0.01), LPA (P &lt; 0.01), MVPA (P &lt; 0.01), and steps (P &lt; 0.01). On the classroom level, more outdoor time was associated with lower BMI percentile and higher MVPA, but outdoor time had different directions of association for SB and LPA on the classroom level. TV viewing time was associated with MVPA (P &lt; 0.01). In TV viewing time, there were differing directions of association at the classroom level. Differing directions indicate that there was no consistent direction of association between classrooms. In conclusion, individual classrooms within centers had different relationships to outdoor time and TV viewing time to movement. Investigating the differences between classrooms may improve movement.

Dog ownership supports the maintenance of physical activity during poor weather in older English adults: cross-sectional results from the EPIC Norfolk cohort

BackgroundDog ownership has been suggested to encourage physical activity in older adults and may enhance resilience to poor environmental conditions. This study investigates the role of dog ownership and walking...

School grade and sex differences in domain-specific sedentary behaviors among Japanese elementary school children: a cross-sectional study

BackgroundIt is vital to reduce the proportion of sedentary behavior in children. Understanding the duration and behavioral context is needed. The present study examined school-grade and sex differences in domain-specific sedentary times and concurrence with screen-time guidelines among Japanese elementary school children.MethodsA total of 625 children (330 boys) were surveyed in 2010 and 2014. Using a questionnaire, data regarding participants’ grade (first through third grades: lower grades; fourth through six grades: higher grades), sex, weight, and height were collected in addition to the time spent per day engaging in each specific sedentary behavior separately: (1) reading or listening to music, (2) TV or video viewing, (3) TV game use, (4) internet use excluding class, (5) homework, and (6) car travel. Two-way analysis of covariance and logistic regression analyses, adjusted for BMI and moderate to vigorous physical activity, were used to examine school-grade and sex differences in sedentary behaviors and the independent risk of exceeding recommended total daily screen time (< 2 h).ResultsOn 625 children, mean minutes (SD) of sedentary behavior per week in (1) – (6) were 90.3 (123.4), 535.0 (356.6), 167.3 (222.1), 23.9 (70.9), 264.9 (185.3), and 33.4 (61.2) in weekdays and 42.1 (70.0), 323.9 (232.0), 123.0 (96.4), 15.8 (49.9), 74.4 (96.4), and 71.3 (84.9) in weekends, respectively. There were differences in the minutes of sedentary behavior between participants of 2010 and 2014; e.g., TV game use and homework in weekdays and weekdays and car travel in weekends. Boys spent more time in TV game use, and girls spent more time reading, listening to music, doing homework, and car travel. Higher-grade students spent more time reading or listening to music, using a computer, and doing homework. Higher-grade students were 2.09 times (95% CI: 1.32 − 3.30) in whole week, 2.08 times (95% CI: 1.45 − 3.00) in weekday, and 1.88 times (95% CI: 1.29 − 2.74) in weekend more likely to spend ≥2 h per day in domains (2) − (4) (screen-time) than lower-grade students.ConclusionsTime spent engaging in each domain-specific sedentary behavior differed according to sex and school grade. Higher-grade students were less likely to meet screen-time guidelines. These findings highlight the need for domain-focused strategies to decrease sedentary behavior in Japanese school-age children.

Breast cancer survivors' beliefs and preferences regarding technology-supported sedentary behavior reduction interventions.

PurposeLess time spent in sedentary behaviors is associated with improved health and disease outcomes in breast cancer survivors. However, little is known about survivors' interest in sedentary behavior reduction interventions and how to effectively reduce this risk behavior. The purpose of this study was to explore breast cancer survivors' interest in and preferences for technology-supported sedentary behavior reduction interventions.MethodsBreast cancer survivors (n = 279; Mage = 60.7 (SD = 9.7)) completed a battery of online questionnaires. Descriptive statistics were calculated for all data. To examine potential relationships between demographic, disease and behavioral factors, and survivors' interest in a technology-supported sedentary behavior reduction intervention, we conducted logistic regression analyses. These same factors were examined in relation to the perceptions of the effectiveness of such intervention using multiple regression analyses.ResultsOn average, survivors spent 10.1 (SD = 4.3) hours/day in sedentary activity. They believed prolonged periods of sedentary behavior were harmful to their health (87.0%) and that reducing sedentary behavior could improve their health (88.4%). Survivors believed they should move around after 30–60 (56.7%) or ≥ 60 (29.9%) minutes of sedentary behavior and indicated they were most likely to replace sedentary behaviors with walking around (97.1%) or walking in place (73.4%). The majority of survivors (79.9%) was interested in participating in a technology-supported sedentary behavior reduction intervention and indicated they would use a smartphone application (61.3%) 2–3 times/day (48.0%), 6 to 7 days/week (52.0%). Most survivors (73.5%) believed reminders would help them decrease sedentary behavior and preferred they be delivered after sitting for 60 minutes (60.5%) via vibrations on a wrist worn activity tracker (77.3%) or text messages (54.4%).ConclusionsTechnology-supported sedentary behavior reduction interventions may be feasible and acceptable to breast cancer survivors. Data regarding user preferences for content, features, delivery mode and design will aid researchers in developing sedentary interventions that are potentially more relevant and effective from the outset.

Sedentary and Physical Activity Habits of Obese Adolescents

Background: The independent association between sedentary behavior (SB) and physical activity (PA) is such that, regardless of accumulated PA, high amounts of SB are detrimental to health, even in adolescents. Purpose: Our aim was to profile activity patterns in free-living environments and to measure levels of SB and light (LT) and moderate (MOD) PA in obese adolescents via accelerometry. Methods: Participants wore Actical accelerometers on the right hip for at least 5 days, from 07:00 am to 11:00 pm. The number of minutes per hour of sedentary, LT, MOD, and vigorous (VIG) activity was calculated using established cut-points. Sixteen subjects (5 males, 11 females;14.8 ± 1.5 years) recorded at least 3 weekdays and 2 weekend days of accelerometry data. Results: Subjects spent a majority of time with SB (727.6 ± 101.2 min/d), followed by LT (212.4 ± 91.6 min/d) and MOD PA (20.5 ± 23.1 min/d). Subjects spent 75.6% of their waking day with SB. Discussion: In addition to low levels of PA, obese adolescents accumulated a substantial number of SB minutes. Translation to Health Education Practice: Minutes of SB are high among obese adolescents. Health educators should design interventions to reduce SB as a complement to programs designed to increase PA.

O-169 Early Programming Of Physical Activity And Sedentary Behaviour At Primary School Age. The Abcd-study

Background and aims Energy balance may be affected by developmental (re)programming of physical activity and sedentary behaviour, hence predispose for cardiovascular disease in later life. We hypothesise that low birth weight and accelerated growth in infancy corresponds with lower physical activity levels and more sedentary behaviour at 8–9 years of age, thereby predisposing for obesity. Methods Physical activity and sedentary behaviour were measured in 183 children (100 boys) of a prospective birth cohort at mean age 8.7 years using accelerometery. Outcomes were minutes per day above moderate activity (>3000 counts/min) and minutes sedentary per day . Results On average (±SD), children participated in 37 (±14) minutes of physical activity and 412 (±45) minutes of sedentary behaviour per day. Low birth weight was not associated with either physical activity or sedentary time. The average standardised growth velocity, however, was positively associated with sedentary time, with an average increase of 7.8 min in daily sedentary time per SD weight gain in infancy. Growth velocity was not significantly associated with physical activity. Conclusions Infant growth may program sedentary behaviour, but not physical activity levels at age 8–9. Birth weight was not related to either physical activity or sedentary behaviour. Hence developmental effects of growth on childhood energy balance correspond with variations in sedentary behaviour rather than physical activity.

Reconsidering the Sedentary Behaviour Paradigm

AimsRecent literature has posed sedentary behaviour as an independent entity to physical inactivity. This study investigated whether associations between sedentary behaviour and cardio-metabolic biomarkers remain when analyses are adjusted for total physical activity.MethodsCross-sectional analyses were undertaken on 4,618 adults from the 2003/04 and 2005/06 U.S. National Health and Nutrition Examination Survey. Minutes of sedentary behaviour and moderate-to-vigorous physical activity (MVPA), and total physical activity (total daily accelerometer counts minus counts accrued during sedentary minutes) were determined from accelerometry. Associations between sedentary behaviour and cardio-metabolic biomarkers were examined using linear regression.ResultsResults showed that sedentary behaviour was detrimentally associated with 8/11 cardio-metabolic biomarkers when adjusted for MVPA. However, when adjusted for total physical activity, the associations effectively disappeared, except for C-reactive protein, which showed a very small, favourable association (β = −0.06) and triglycerides, which showed a very small, detrimental association (β = 0.04). Standardised betas suggested that total physical activity was consistently, favourably associated with cardio-metabolic biomarkers (9/11 biomarkers, standardized β = 0.08–0.30) while sedentary behaviour was detrimentally associated with just 1 biomarker (standardized β = 0.12).ConclusionThere is virtually no association between sedentary behaviour and cardio-metabolic biomarkers once analyses are adjusted for total physical activity. This suggests that sedentary behaviour may not have health effects independent of physical activity.

Objective Assessment of Activity, Energy Expenditure, and Functional Limitations in Older Men: The Osteoporotic Fractures in Men Study

The relationship between objectively assessed activity, energy expenditure, and the development of functional limitations is unknown. Energy expenditure and activity levels were measured objectively using the multisensor SenseWear Pro Armband worn for greater than or equal to 5 days in 1,983 MrOS men (aged ≥ 78.3 years) free of functional limitations. Validated algorithms calculated energy expenditure; standard cut points defined moderate or greater activity (≥ 3.0 METS); and sedentary behavior (time awake ≤ 1.5 METS). Self-reported functional limitation was determined at the activity assessment and 2.0 years later as inability to perform instrumental activities of daily living (managing money, managing medications, shopping, housework, and meal preparation) and activities of daily living (climb stairs, walk two to three blocks, transfer, or bathe). Each standard deviation decrease in total energy expenditure (420.6 kcal/day) increased the likelihood of inability to perform an instrumental activity of daily living (multivariate odds ratio [mOR]: 1.61, 95% CI: 1.30-2.00) or activity of daily living (mOR: 1.35, 95% CI: 1.12-1.63). Each standard deviation decrease in moderate or greater activity (61.1 minutes/day) increased the likelihood of inability to perform an instrumental activity of daily living (mOR: 1.47, 95% CI: 1.22-1.78) or activity of daily living (mOR: 1.36, 95% CI: 1.14-1.61). Each standard deviation increase in minutes of sedentary behavior (105.2 minutes/day) increased the likelihood of inability to perform an instrumental activity of daily living (mOR: 1.20, 95% CI: 1.03-1.40) or activity of daily living (mOR: 1.17, 95% CI: 1.01-1.35). Older men with lower total energy expenditure, lower moderate activity, or greater sedentary time were more likely to develop a functional limitation.

Discrepancies in accelerometer-measured physical activity in children due to cut-point non-equivalence and placement site

This study examined dissonance in physical activity (PA) between two youth-specific hip-derived intensity cut-points for the Actiwatch (AW), and compared PA between hip and wrist placements using site-specific cut-points. Twenty-four children aged 11.2 ± 0.5 years wore the AW on the right hip and non-dominant wrist during a typical school day. Minutes of sedentary behaviour and vigorous activity were greater using Puyau et al. (2002) cut-points, but light, moderate, and moderate-to-vigorous (MVPA) were greater when derived using Puyau et al. (2004) cut-points (P < 0.01). Total hip activity counts were lower than wrist. Sedentary minutes were greater at the hip, but minutes of light, vigorous and MVPA were lower (P < 0.01). Moderate minutes were greater at the hip, but differed only when applying the Puyau et al. (2004) cut-points (P < 0.01). In conclusion, data comparisons between two hip derived AW cut-points and between hip and wrist data are inappropriate. Future researchers using the AW at the hip should present data reduced using both published cut-points. As hip and wrist data differ, the wrist placement is preferable as it will likely increase children's compliance to monitoring protocols due to reduced obtrusiveness compared to the hip.

Physical Activity Levels of Adolescent Girls During Dance Classes

The aims of this study were to describe the physical activity levels of girls during dance classes and to identify factors associated with moderate-to-vigorous physical activity (MVPA) in those classes. Participants were 137 girls (11 to 18 years-old) enrolled in ballet, jazz, or tap dance classes from 11 dance studios. Participants wore an accelerometer during the selected dance class on 2 separate days. Factors hypothesized to be associated with MVPA were dance style, instructional level, instructor's experience, percent of class time spent in choreography, and participants' age, race/ethnicity, BMI-for-age percentile, and years of dance training. Data were analyzed using generalized linear mixed models. Girls engaged in 9.8 minutes of MVPA, 6.0 minutes of moderate, 3.8 minutes of vigorous, 39.3 minutes of light, and 10.9 minutes of sedentary behavior per hour of dance class participation. Jazz/tap classes provided more MVPA than ballet classes, and intermediate level classes provided more MVPA than advanced level classes. Girls with more dance training obtained more MVPA than girls with less dance training. Dance classes provide valuable opportunities for adolescent girls to be physically active.

Myopia and later physical activity in adolescence: a prospective study

Objectives:To investigate associations between objectively measured physical activity (PA) and myopia in children.Methods:Children from the Avon Longitudinal Study of Parents and Children (ALSPAC) were asked to wear a uniaxial accelerometer...

Intraindividual Variation of Objectively Measured Physical Activity in Children

This study examined the seasonal and intraindividual variation in objectively measured physical activity in 11- to 12-yr-olds. Children were asked to wear a uniaxial accelerometer for 7 d four times throughout the course of about a year. A random-intercepts model was used to separate the inter- and intraindividual components of physical activity. Gender, age, body mass index (BMI), height, and month of measurement were fitted to the model as potential confounders. A total of 315 children had valid data for at least two measurement occasions, and 244 had data for all four measurement occasions. The unadjusted intraclass correlation coefficient (ICC) for total activity (counts per minute) was 0.54; 0.49 after adjusting for gender, age, and BMI; and 0.53 after adjusting for gender, age, BMI, and month. Further adjustment for pubertal status at baseline had no effect on the ICC. Restricting the analysis to only those with data for all four measurement occasions (N=244), or to measurements taken on school days only, had no effect on the ICC. The fully adjusted ICC was 0.51 for weekdays only and 0.39 for weekend days only. For minutes of moderate to vigorous physical activity, minutes of vigorous activity, minutes of sedentary behavior, and number of 30-min blocks of sedentary behavior, the fully adjusted ICC were 0.45, 0.37, 0.59, and 0.39, respectively. The analysis was repeated for boys and girls separately, but the differences in ICC were small. There was substantial intraindividual variation in the objectively measured physical activity of these children. Studies using single a measurement occasion where physical activity is the exposure should take this into account to adjust for regression dilution.