Step based physical activity guidelines for preschool-aged children

ObjectivePublic health organizations recommend that preschool-aged children accumulate at least 3 h of physical activity (PA) daily. Objective monitoring using pedometers offers an opportunity to measure preschooler's PA and assess compliance with this recommendation. The purpose of this study was to derive step-based recommendations consistent with the 3 h PA recommendation for preschool-aged children.MethodThe study sample comprised 916 preschool-aged children, aged 3 to 6 years (mean age = 5.0 ± 0.8 years). Children were recruited from kindergartens located in Portugal, between 2009 and 2013. Children wore an ActiGraph GT1M accelerometer that measured PA intensity and steps per day simultaneously over a 7-day monitoring period. Receiver operating characteristic (ROC) curve analysis was used to identify the daily step count threshold associated with meeting the daily 3 hour PA recommendation.ResultsA significant correlation was observed between minutes of total PA and steps per day (r = 0.76, p < 0.001). The optimal step count for ≥ 3 h of total PA was 9099 steps per day (sensitivity (90%) and specificity (66%)) with area under the ROC curve = 0.86 (95% CI: 0.84 to 0.88).ConclusionPreschool-aged children who accumulate less than 9000 steps per day may be considered Insufficiently Active.     

Implementing classroom physical activity breaks: Associations with student physical activity and classroom behavior

ObjectiveTo investigate the relation of classroom physical activity breaks to students' physical activity and classroom behavior.MethodsSix elementary-school districts in California implemented classroom physical activity interventions in 2013–2014. Students' (N = 1322) accelerometer-measured moderate-to-vigorous physical activity (MVPA) during school and teachers' (N = 397) reports of implementation and classroom behavior were assessed in 24 schools at two time points (both post-intervention). Mixed-effects models accounted for nested data.ResultsMinutes/day of activity breaks was positively associated with students' MVPA (βs = .07–.14; ps = .012–.016). Students in classrooms with activity breaks were more likely to obtain 30 min/day of MVPA during school (OR = 1.75; p = .002). Implementation was negatively associated with students having a lack of effort in class (β = − .17; p = .042), and student MVPA was negatively associated with students being off task or inattentive in the classroom (β = − .17; p = .042). Students provided with 3–4 physical activity opportunities (classroom breaks, recess, PE, dedicated PE teacher) had ≈ 5 more min/day of school MVPA than students with no opportunities (B = 1.53 min/opportunity; p = .002).ConclusionsImplementing classroom physical activity breaks can improve student physical activity during school and behavior in the classroom. Comprehensive school physical activity programs that include classroom-based activity are likely needed to meet the 30 min/day school physical activity guideline.     

Joint effects of objectively-measured sedentary time and physical activity on all-cause mortality

ObjectiveExamine the joint effects of objectively-measured sedentary time and moderate-to-vigorous physical activity (MVPA) on all-cause mortality.MethodsThe present study included data from the 2003–2006 National Health & Nutrition Examination Survey, with mortality follow-up data (via National Death Index) through 2011 (N = 5575 U.S. adults). Sedentary time (activity counts/min between 0 and 99) and MVPA (activity counts/min ≥ 2020) were objectively measured using the ActiGraph 7164 accelerometer.ResultsThe median age of the participants was 50 yrs; proportion of men was 50.2%; proportion of whites was 53.8%, 18.7% for blacks; median follow-up was 81 months; and 511 deaths occurred over the follow-up period. After adjusting for age, gender, race-ethnicity, cotinine, weight status, poverty level, C-reactive protein and comorbid illness (summed score of 0–8 chronic diseases), and for a 1 min increase in MVPA and sedentary time, both MVPA (HR_adjusted = 0.98; 95% CI: 0.96–0.99; P = 0.04) and sedentary time (HR_adjusted = 1.001; 95% CI: 1.0003–1.002; P = 0.008) were independently associated with all-cause mortality. Further, MVPA was associated with all-cause mortality among those with greater (above median) sedentary time (HR_adjusted = 0.95; 95% CI: 0.93–0.97; P < .001). Sedentary time was not associated with all-cause mortality among those engaging in above median levels of MVPA (HR_adjusted = 0.998; 95% CI: 0.996–1.001; P = .32), but sedentary time was associated with increased mortality risk among those below median levels of MVPA (HR = 1.002; 95% CI: 1.001–1.003; P < 0.001).ConclusionsSedentary time and MVPA are independently associated with all-cause mortality. Above median sedentary time levels did not negate the beneficial effects of MVPA on all-cause mortality risk.     

Pedometer-assessed physical activity of Singaporean youths

ObjectiveThe aim of the study was to investigate the pedometer-assessed physical activity of Singaporean youths using an objective measurement of physical activity.Methods and resultsPedometer step count was monitored over the entire week in 877 participants aged 9–18 years in three schooling cohorts [primary (age, 9–12 years; n = 150 males; 156 females), secondary (age, 13–16 years; n = 137 males; 138 females) and junior college (age, 17–18 years; n = 140 males; 156 females)] in Singapore during July to September 2009. Analyses identified significant main effects for step count taken outside of school compared to within school (mean (SD): 5568 (4796) vs. 3881 (3149), p < 0.05). However, no significant difference was found for steps accumulated within or outside school in boys and girls across the schooling levels (steps × sex × level interaction, p > 0.05). Step counts were not significantly different between weekdays or weekends (9719 (6063) vs. 9483 (8056), p > 0.05), across schooling levels and between male and female participants (sex × level and steps × level × sex interactions, all p > 0.05).ConclusionStep count decline is drastic for male adolescents after primary school but remains low across the schooling levels for female participants. Aggregated daily step count fell short by up to 35% of the 16,000 and 13,000 steps recommended respectively for male and female youths.     

Physical activity outcomes in afterschool programs: A group randomized controlled trial

IntroductionAfterschool programs (ASPs) across the US are working towards achieving the standard of all children accumulating 30 min of moderate-to-vigorous physical activity (MVPA) during program time. This study describes the two-year impact of an intervention designed to assist ASPs meeting the 30 min/day MVPA standard.MethodsUsing a two-year delayed treatment, group randomized controlled trial, 20 ASPs serving ~ 1700 children/year (6–12 yrs) were randomized to either an immediate (n = 10, baseline-2013 and 2 yrs intervention fall-2013-to-spring-2015) or delayed group (n = 10, baseline 2013–2014 and 1 yr intervention fall-2014-to-spring-2015). The intervention, Strategies-To-Enhance-Practice (STEPs), focused on programming MVPA in the daily schedule, training of staff and leaders, and ongoing technical support/assistance. Accelerometry-derived proportion of children meeting the 30 min/day MVPA standard was measured in the spring of each year. Mixed model logistic regressions were used to examine the change in the odds of achieving the MVPA standard. Analyses were conducted in 2015. Data were collected in one southeastern US state.ResultsImmediate boys (n = 677) and delayed girls (n = 658) increased the percent achieving 30 min MVPA/day from 35.9% to 47.0% (odds ratio [OR] = 1.88, 95% CI 1.18–3.00) and 13.1% to 19.1% (OR = 1.42, 95% CI 1.03–1.96). Immediate girls (n = 613) and delayed boys (n = 687) exhibited a nonsignificant increase from 19.1% to 21.6% (OR = 1.20, 95% CI 0.84–1.72) and 29.0% to 31.3% (OR = 1.13, 95%CI 0.80–1.58).ConclusionsSTEPs can have an impact on children's MVPA and time spent sedentary, yet was unable to fully achieve the goal of all children accumulating 30 min MVPA/day. Additional efforts are need to identify strategies ASPs can use to meet this important public health standard.     

The effect of a school-centered multicomponent intervention on daily physical activity and sedentary behavior in primary school children: The Active Living study

The aim of the current study was to examine the effectiveness of a school-centered multicomponent PA intervention, called ‘Active Living’, on children's daily PA levels.A quasi-experimental design was used including 9 intervention schools and 9 matched control schools located in the Netherlands. The baseline measurement took place between March–June 2013, and follow-up measurements were conducted 12 months afterwards. Accelerometer (ActiGraph, GT3X +) data of 520 children aged 8–11 years were collected and supplemented with demographics and weather conditions data. Implementation magnitude of the interventions was measured by keeping logbooks on the number of implemented physical environmental interventions (PEIs) and social environmental interventions (SEIs). Multilevel multivariate linear regression analyses were used to study changes in sedentary behavior (SB), light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) between baseline and follow-up. Finally, effect sizes (ESs) were calculated using Cohen's d.No pooled effects on PA and SB were found between children exposed and not exposed to Active Living after 12 months. However, children attending Active Living schools that implemented larger numbers of both PEIs and SEIs engaged in 15 more minutes of LPA per weekday at follow-up than children in the control condition (ES = 0.41; p < .05). Moreover, children attending these schools spent less time in SB at follow-up (ES = 0.33), although this effect was non-significant. No significant effects were found on MVPA.A school-centered multicomponent PA intervention holds the potential to activate children, but a comprehensive set of intervention elements with a sufficient magnitude is necessary to achieve at least moderate effect sizes.     

Empowering adolescents to be physically active: Three-year results of the Sigue la Huella intervention

ObjectiveTo examine the effects of a school-based intervention called Sigue la Huella (Follow the Footstep) on adolescents' daily moderate-to-vigorous physical activity (MVPA).MethodThis quasi-experimental, cohort study took place in four secondary schools in Huesca (Spain) during the 2009–2010, 2010–2011, and 2011–2012 academic years (students aged 12–15 years). Two schools were assigned to the experimental condition (n = 368) and two schools to the control condition (n = 314). Sigue la Huella was based on the social ecological model and self-determination theory. MVPA was measured for 7 days on 4 occasions using accelerometers. Data were analyzed with individual growth curve models.ResultsThere was a significant difference in linear growth rate of daily MVPA between the experimental and the control group, independent of study wave, type of school (public vs. private), grade level and gender (p < 0.001). Specifically, MVPA increased in the experimental group (β = 7.02, 95% confidence interval (CI) = 1.27 to 12.78, p = 0.017) and tended to decrease in the control group (β = − 5.26, 95% CI = − 11.17 to 0.65, p < 0.081). The observed increase was larger in boys than in girls (p = 0.003).ConclusionsSigue la Huella had a positive effect on adolescents' daily MVPA over three school years. Both genders benefited from the intervention, although boys to a greater extent.     

Daily movement patterns and predicted 10-yr risk for a first atherosclerotic cardiovascular disease (ASCVD) event using the pooled cohort risk equations among US adults

ObjectiveExamine the association between movement patterns and predicted risk of a first atherosclerotic cardiovascular disease (ASCVD) event.MethodsData from the 2003–2006 National Health and Nutrition Examination Survey (NHANES) were used (40–79 yrs; N = 2421). Participants wore an ActiGraph 7164 accelerometer to create four movement pattern groups; Group 1: ≥ 150 min/wk of moderate-to-vigorous physical activity (MVPA) and light-intensity physical activity (LIPA) ≥ sedentary behavior (SB); Group 2: ≥ 150 min/wk of MVPA and LIPA < SB; Group 3: < 150 min/wk of MVPA and LIPA ≥ SED; and Group 4: < 150 min/wk of MVPA and LIPA < SB. 10-yr risk for a first ASCVD event was estimated using the pooled cohort equations.ResultsAfter adjusting for age, gender, race–ethnicity and obesity, Group 2 (β = − 0.28; p = 0.44) was not significantly different than Group 1, but Groups 3 (β = 1.09; p = 0.01) and 4 (β = 1.44; p < 0.001) had a higher pooled risk score.ConclusionsThose in the least desirable movement pattern (Group 4) had the highest pooled risk score. Given the similar risk scores for Groups 1 and 2, future research is needed to determine if sufficient MVPA can counteract the potential consequences associated with an imbalanced LIPA:SB ratio (i.e., LIPA < SB).     

Innovation to motivation—pilot study of a mobile phone intervention to increase physical activity among sedentary women

ObjectivesThis uncontrolled pilot study assessed changes in pedometer-measured step counts and self-reported physical activity during a 3-week mobile phone-based intervention. We also explored whether age, BMI, and psychosocial factors were associated with changes in step counts.MethodsForty-one sedentary adult women in San Francisco, California were asked to report their pedometer steps using a study-supplied mobile phone from June to September 2008. In the second and third weeks, daily prompts delivered by the mobile phone encouraged participants to increase steps by 20% from the previous week.ResultsMean age was 48 years. Average daily total steps increased by approximately 800 or 15% over three weeks (p < 0.001). Lower BMI, no antidepressant use, and lower self-reported health status were associated with higher step counts at baseline. Improvements in self-reported will-power were associated with increases in step counts (p < 0.001). Neither age (p = 0.55) nor BMI (p = 0.13) was significantly associated with changes in activity over the 3 weeks.ConclusionsThe intervention appeared to motivate sedentary women to increase their physical activity. A randomized controlled clinical trial is warranted and feasible.     

Accelerometer steps/day translation of moderate-to-vigorous activity

Physical activity (PA) guidelines are typically communicated in terms of duration, frequency and intensity, e.g., 30 min/day of moderate-to-vigorous physical activity (MVPA) on at least 5 days/week. Step counters can be used to collect objective PA expressed as steps/day, however the association between steps/day and recommended PA levels is unclear.ObjectiveWe determined a direct steps/day translation of 30 min/day accumulated MVPA, using concurrently detected ActiGraph accelerometer-defined step and activity count data collected as part of the 2005–2006 National Health and Nutrition Examination Survey (NHANES).MethodWe employed statistical models to analyze data from 3523 participants 20+ years of age who wore the accelerometer for at least one valid day (i.e., at least 10/24 h) over 7 days.Results30 min/day of MVPA translated to approximately 7900 steps/day for males and 8300 steps/day for females. In a subsample of participants (n = 1197) with valid data on all 7 days, we found 150 min/week of MVPA translated to approximately 7000 steps/day (or 49,000 steps/week).ConclusionAccumulating approximately 8000 steps/day is a good proxy for 30 min of daily MVPA, while accumulating 7000 steps/day every day of the week is consistent with obtaining 150 min of weekly MVPA.     

CANPLAY study: Secular trends in steps/day amongst 5–19 year-old Canadians between 2005 and 2014

IntroductionThe Canadian Physical Activity Levels Among Youth (CANPLAY) study collected pedometer data from eight surveys between 2005 and 2014, making it a unique database of objective population physical activity surveillance. The purpose of this study was to describe secular physical activity trends for 5–19 year olds.MethodsCanadian children from nationally representative samples (10,000 recruited, n ≅ 5500 per survey) were mailed a pedometer kit, asked to wear the pedometer for 7 consecutive days, log steps daily, then return the log by mail. Weighted medians and prevalence estimates were calculated. Trends were tested by χ² test of independence.ResultsAn overall median of 10,935 steps/day was taken by Canadian children 5–19 years of age (n = 43,806) across the eight surveys. Steps/day increased between 2005–06 and 2007–08, then decreased in 2012–14. The prevalence of taking sufficient steps/day (defined as ≥ 10,000 steps/day for 5 year olds, ≥ 13,000 steps/day for 6–11 year-old boys; ≥ 11,000 steps/day for 6–11 year-old girls; and ≥ 10,000 steps/day for 12–19 year olds;) also increased then decreased over time, whereas the prevalence of accumulating < 7000 steps/day generally increased over time. Trends were significant for boys, girls and each age group.DiscussionThe CANPLAY surveillance system provided comparable data at multiple time points over 9 years. An overall shift in the distribution of steps/day towards a less active lifestyle occurred between 2005–06 and 2012–14 for boys, girls and each age group. This provides evidence that the national policy goal to increase children's steps/day by 2015 has not been met.     

Objectively measured physical activity,sedentary time and subclinical vascular disease: Cross-sectional study in older British men

Low physical activity (PA) and high levels of sedentary time (ST) are associated with higher cardiovascular disease (CVD) risk among older people. However, their independent contribution and importance of duration of PA and ST bouts remain unclear. We investigated associations between objectively measured PA, ST and non-invasive vascular measures, markers of CVD risk.Cross-sectional study of 1216 men from the British Regional Heart Study, mean age 78.5 years, measured in 2010–2012. Carotid intima thickness (CIMT), distensibility coefficient (DC) and plaque presence were measured using ultrasound; pulse wave velocity (cfPWV) and augmentation index (AIx) using a Vicorder. PA and ST were measured using hip-worn ActiGraph GT3X accelerometers.After adjusting for covariates, each additional 1000 steps per day was associated with a 0.038 m/s lower cfPWV (95% CI = − 0.076, 0.0003), 0.095 10^− 3 kPa^− 1 higher DC (95% CI = 0.006, 0.185), 0.26% lower AIx (95% CI = − 0.40, − 0.12) and a 0.005 mm lower CIMT (95% CI = − 0.008, − 0.001). Moderate and vigorous PA (MVPA) was associated with lower AIx and CIMT, light PA (LPA) with lower cfPWV and CIMT and ST with higher cfPWV, AIx and CIMT and lower DC. LPA and ST were highly correlated (r = − 0.62). The independence of MVPA and ST or MVPA and LPA was inconsistent across vascular measures. Bout lengths for both PA and ST were not associated with vascular measures.In our cross-sectional study of older men, all PA regardless of intensity or bout duration was beneficially associated with vascular measures, as was lower ST. LPA was particularly relevant for cfPWV and CIMT.     

The association between physical activity and liver fat after five years of follow-up in a primary prevention multi-ethnic cohort

Objective: Excess liver fat (LF) is associated with dyslipidemia, insulin resistance and cardiovascular disease. Evidence suggests that there is an independent relationship between physical activity (PA) and LF although little is known of the role of PA intensity in reducing LF. The purpose was to evaluate whether meeting PA guidelines, the amount of PA and the intensity of PA at baseline were associated with LF after five-years.Methods: Men and women (n = 478) living in Vancouver, Canada of Aboriginal, Chinese, European or South Asian background completed baseline measurements in 2004–2005. Liver fat was assessed using CT scans at 5-year follow-up, and PA using a PA questionnaire at baseline as well as demographics and anthropometry.Results: In separate unadjusted models, meeting moderate–vigorous PA (MVPA) guidelines (p = 0.009), vigorous PA (p = 0.002) and MVPA (p = 0.017) but not moderate PA (p = 0.068) was predictive of LF at five years (p = 0.009). In multiple linear regression models, when adjusted for covariates, meeting MVPA guidelines and MVPA with LF at five years was no longer significant (p > 0.05) while vigorous PA remained significant (p = 0.021).Conclusion: Meeting PA guidelines through MVPA may not be adequate to prevent the accumulation of LF and PA guidelines may require revision. Vigorous PA should be encouraged to prevent LF accumulation.     

Investigating links between moderate-to-vigorous physical activity and cognitive performance in elementary school students

BackgroundResearch has noted both physical and psychological benefits when children participate in physical activity. Recent studies indicate there may also be academic benefits and students may be more efficient learners after physical activity. This study investigated the influence of moderate-to-vigorous physical activity (MVPA) on four cognitive processes: planning, attention, simultaneous processing, and successive processing.MethodsParticipants were two classes of fourth-grade students in Ontario (n = 40). Using a counterbalanced design, students in the two classes completed standardized tests for each cognitive process both after no physical activity and following it (20 min MVPA within a 45 min lesson).ResultsThe results indicate that performance on the planning test significantly improved after physical activity (p < 0.001), controlling for sequence and habituation/retesting effects. No improvement was observed for attention, simultaneous processing, or successive processing.ConclusionPlanning is associated with problem solving skills and behaviour self-regulation. These skills may be improved in elementary school students immediately following physical activity.     

The PLUNGE randomized controlled trial: Evaluation of a games-based physical activity professional learning program in primary school physical education

ObjectiveTo evaluate the efficacy of the Professional Learning for Understanding Games Education (PLUNGE) program on fundamental movement skills (FMS), in-class physical activity and perceived sporting competence.MethodsA cluster-randomized controlled trial involving one year six class each from seven primary schools (n = 168; mean age = 11.2 years, SD = 1.0) in the Hunter Region, NSW, Australia. In September (2013) participants were randomized by school into the PLUNGE intervention (n = 97 students) or the 7-week wait-list control (n = 71) condition. PLUNGE involved the use of Game Centered curriculum delivered via an in-class teacher mentoring program. Students were assessed at baseline and 8-week follow-up for three object control FMS (Test of Gross Motor Development 2), in-class physical activity (pedometer steps/min) and perceived sporting competence (Self-perception Profile for Children).ResultsLinear mixed models revealed significant group-by-time intervention effects (all p < 0.05) for object control competency (effect size: d = 0.9), and in-class pedometer steps/min (d = 1.0). No significant intervention effects (p > 0.05) were observed for perceived sporting competence.ConclusionsThe PLUNGE intervention simultaneously improved object control FMS proficiency and in-class PA in stage three students.     

Physically active vs. sedentary academic lessons: A dose response study for elementary student time on task

BackgroundPhysically active academic lessons are an effective intervention to reduce sedentary time and increase student physical activity. They have also been shown to enhance task engagement, as indicated by observations of attention and behavior control, time on task (TOT). However, it is not clear if the improved TOT stems from the physical activity or if it is the result of an enjoyable break from traditional instruction. If it is due to physical activity, what dose of intensity is required for the effect? This study was designed to test these questions.MethodsParticipants were 320 children (7–9 years) recruited from school districts in Central Texas in 2012. They were assigned by classroom (n = 20) to one of four conditions: 1) sedentary, standard lesson (n = 72); 2) sedentary academic game (n = 87); 3) low to moderate intensity PA (LMPA), academic game (n = 81); and 4) moderate to vigorous intensity PA (MVPA), academic game (n = 76). Measures included PA via accelerometer and TOT.ResultsMixed-method RMANOVA indicated TOT decreased following the standard lesson (p < 0.001), showed no change following the sedentary academic game (p = 0.68), and increased following the LMPA (p < 0.01) and MVPA (p < 0.001) academic games.ConclusionsWhile the sedentary, academic game prevented the reduction in TOT observed in the standard lesson, PA resulted in increased TOT. Future research should be designed to examine the potential academic benefits of the change in TOT.     

The association between discrepant weight perceptions and objectively measured physical activity

BackgroundSome individuals perceive themselves as being normal weight, despite having an excess body fat percentage (e.g., underestimate weight). Conversely, other individuals perceive themselves as being overweight, despite having a normal body fat percentage (e.g., overestimate weight). When perceived and actual weight statuses are incongruent, individuals possess a discrepant weight perception. The association between discrepant weight perceptions and engagement in moderate-to-vigorous physical activity (MVPA) has not been thoroughly investigated, which was this study's purpose.MethodsFor this cross-sectional study, data from the 2003–2006 National Health and Nutrition Examination Survey were utilized (N = 5462 adults). MVPA was assessed via accelerometry. Based on measured body mass index and whether participants considered themselves as overweight, underweight, or about the right weight, we classified individuals as accurate perception, overestimate weight (discrepant), or underestimate weight (discrepant). A negative binomial logistical regression was used to assess the association between discrepant weight perception (independent variable) and engagement in MVPA (outcome variable).ResultsFemales who said that they are normal weight, but were in fact overweight based on body mass index, engaged in 13% less MVPA (rate ratio = .87, 95% confidence interval: .769–.999, P = .05). Also, older adults (> 60 yrs) who said that they are normal weight, but were overweight based on body mass index, engaged in 23% less MVPA (rate ratio = .77, 95% confidence interval: .616–.965, P = .025).ConclusionDiscrepant weight perceptions were associated with less objectively measured MVPA. Interventions should take weight perceptions into consideration when designing and evaluating intervention impact.     

Developmental trajectories of physical activity during elementary school physical education

ObjectivePhysical education (PE) during school provides an opportunity for children to be physically active. Few empirical studies have investigated developmental trajectories and determinants of objective moderate to vigorous physical activity (MVPA) during PE classes. The purpose of this study was to examine the developmental trajectories and determinants of MVPA during PE lessons in young children (8–12 years of age) in primary schools.MethodsStudents in grades 5–7 (n = 1202; 51.2% girls) were recruited from 17 elementary schools from the Geneva canton in 2012–2013. The percentage of time spent in accelerometer-assessed MVPA during regular PE lessons was used as a dependent variable.ResultsLinear mixed-model analyses revealed (a) that boys had a higher percentage of MVPA than girls, but none of the children reached the recommended activity levels (i.e., 50% of the PE class time spent in MVPA), (b) a linear decrease in the percentage of MVPA with age, (c) that higher perceived competence predicted a higher percentage of MVPA, and (d) that higher perceived competence reduced the negative linear effect of age among boys, but not among girls.ConclusionThe percentage of PE time spent in MVPA did not reach recommendations made by Centers for Disease Control and Prevention and decreased from 8 to 12 years old both for boys and girls. Perceived competence appears crucial to reduce MVPA decline for boys, but not for girls.     

Twenty-four hour dietary recalls by fourth-grade children were not influenced by observations of school meals

ObjectiveTo investigate whether school-meal observations influenced children's 24-hour dietary recalls.Study Design and SettingOver three school years, 555 randomly selected fourth-grade children were interviewed to obtain a 24-hour dietary recall; before being interviewed, 374 children were observed eating two school meals (breakfast, lunch), and 181 children were not observed. Within observation-status groups (observed, unobserved), children were randomized within sex to one of six combinations from two target periods (prior 24 hours, previous day) crossed with three interview times (morning, afternoon, evening).ResultsFor each of the five variables (interview length, meals/snacks, meal components, items, kilocalories), naïve and adjusted equivalence tests rejected that observation-status groups were different, indicating that school-meal observations did not influence children's 24-hour dietary recalls. There was a target-period effect on length (P < 0.0001) (longer for prior-24-hour recalls), a school year effect on length (P = 0.0002) (longer for third year), and a target period–interview time interaction on items (P = 0.0110) and kilocalories (P = 0.0047) (both smaller for previous-day recalls in the afternoon than prior-24-hour recalls in the afternoon and previous-day recalls in the evening), indicating that variables were sufficiently sensitive and psychometrically reliable.ConclusionConclusions about 24-hour dietary recalls by fourth-grade children observed eating school meals in validation studies are generalizable to 24-hour dietary recalls by comparable but unobserved children in nonvalidation studies.     

Daily movement patterns and biological markers among adults in the United States

ObjectiveTo examine the combined effects of sedentary (SED), light (LPA) and moderate-to-vigorous physical activity (MVPA) on biological markers among a nationally representative sample of U.S. adults.MethodsData from the 2003–2006 NHANES study was used, with 5580 adults (≥ 20 years) included in the study. Participants wore an ActiGraph 7164 accelerometer with accelerometry data used to create four movement pattern groups: ≥ 150 min/week of MVPA and LPA ≥ SED; ≥ 150 min/week of MVPA and LPA < SED; < 150 min/week of MVPA but LPA ≥ SED; and < 150 min/week of MVPA and LPA < SED. Blood samples were taken to assess various biological parameters (e.g., cholesterol).Results47.2% (SE: 1.2) of Americans engaged in < 150 min/week of MVPA and had a negative LPA–SED balance. In general, participants who engaged in ≥ 150 min/week of MVPA, regardless of LPA–SED balance, had more favorable biological levels; however, there was evidence showing that even if individuals engaged in < 150 min/week of MVPA, but if their LPA exceeded SED, they had more favorable levels of triglycerides and insulin.ConclusionsPrograms are needed to increase American's engagement in MVPA, and also ensure that LPA exceeds SED behavior.