Stephen D. Herrmann

2011 Compendium of Physical Activities: A Second Update of Codes and MET Values

PURPOSE The Compendium of Physical Activities was developed to enhance the comparability of results across studies using self-report physical activity (PA) and is used to quantify the energy cost of a wide variety of PA. We provide the second update of the Compendium, called the 2011 Compendium. METHODS The 2011 Compendium retains the previous coding scheme to identify the major category headings and specific PA by their rate of energy expenditure in MET. Modifications in the 2011 Compendium include cataloging measured MET values and their source references, when available; addition of new codes and specific activities; an update of the Compendium tracking guide that links information in the 1993, 2000, and 2011 compendia versions; and the creation of a Web site to facilitate easy access and downloading of Compendium documents. Measured MET values were obtained from a systematic search of databases using defined key words. RESULTS The 2011 Compendium contains 821 codes for specific activities. Two hundred seventeen new codes were added, 68% (561/821) of which have measured MET values. Approximately half (317/604) of the codes from the 2000 Compendium were modified to improve the definitions and/or to consolidate specific activities and to update estimated MET values where measured values did not exist. Updated MET values accounted for 73% of all code changes. CONCLUSIONS The Compendium is used globally to quantify the energy cost of PA in adults for surveillance activities, research studies, and, in clinical settings, to write PA recommendations and to assess energy expenditure in individuals. The 2011 Compendium is an update of a system for quantifying the energy cost of adult human PA and is a living document that is moving in the direction of being 100% evidence based.

Aerobic exercise alone results in clinically significant weight loss for men and women: Midwest Exercise Trial-2

Exercise is recommended by public health agencies for weight management; however, the role of exercise is generally considered secondary to energy restriction. Few studies exist that have verified completion of exercise, measured the energy expenditure of exercise, and prescribed exercise with equivalent energy expenditure across individuals and genders.

Does Increased Exercise or Physical Activity Alter Ad-Libitum Daily Energy Intake or Macronutrient Composition in Healthy Adults? A Systematic Review

Background The magnitude of the negative energy balance induced by exercise may be reduced due to compensatory increases in energy intake. Objective To address the question: Does increased exercise or physical activity alter ad-libitum daily energy intake or macronutrient composition in healthy adults? Data Sources PubMed and Embase were searched (January 1990–January 2013) for studies that presented data on energy and/or macronutrient intake by level of exercise, physical activity or change in response to exercise. Ninety-nine articles (103 studies) were included. Study Eligibility Criteria Primary source articles published in English in peer-reviewed journals. Articles that presented data on energy and/or macronutrient intake by level of exercise or physical activity or changes in energy or macronutrient intake in response to acute exercise or exercise training in healthy (non-athlete) adults (mean age 18–64 years). Study Appraisal and Synthesis Methods Articles were grouped by study design: cross-sectional, acute/short term, non-randomized, and randomized trials. Considerable heterogeneity existed within study groups for several important study parameters, therefore a meta-analysis was considered inappropriate. Results were synthesized and presented by study design. Results No effect of physical activity, exercise or exercise training on energy intake was shown in 59% of cross-sectional studies (n = 17), 69% of acute (n = 40), 50% of short-term (n = 10), 92% of non-randomized (n = 12) and 75% of randomized trials (n = 24). Ninety-four percent of acute, 57% of short-term, 100% of non-randomized and 74% of randomized trials found no effect of exercise on macronutrient intake. Forty-six percent of cross-sectional trials found lower fat intake with increased physical activity. Limitations The literature is limited by the lack of adequately powered trials of sufficient duration, which have prescribed and measured exercise energy expenditure, or employed adequate assessment methods for energy and macronutrient intake. Conclusions We found no consistent evidence that increased physical activity or exercise effects energy or macronutrient intake.

Impact of accelerometer wear time on physical activity data: a NHANES semisimulation data approach

Background Current research practice employs wide-ranging accelerometer wear time criteria to identify a valid day of physical activity (PA) measurement. Objective To evaluate the effects of varying amounts of daily accelerometer wear time on PA data. Methods A total of 1000 days of accelerometer data from 1000 participants (age=38.7±14.3 years; body mass index=28.2±6.7 kg/m2) were selected from the 2005–2006 National Health and Nutrition Examination Study data set. A reference data set was created using 200 random days with 14 h/day of wear time. Four additional samples of 200 days were randomly selected with a wear time of 10, 11, 12 and 13 h/day1. These data sets were used in day-to-day comparison to create four semisimulation data sets (10, 11, 12, 13 h/day) from the reference data set. Differences in step count and time spent in inactivity (<100 cts/min), light (100–1951 cts/min), moderate (1952–5724 cts/min) and vigorous (≥5725 cts/min) intensity PA were assessed using repeated-measures analysis of variance and absolute percent error (APE). Results There were significant differences for moderate intensity PA between the reference data set and semisimulation data sets of 10 and 11 h/day. Differences were observed in 10–13 h/day1 for inactivity and light intensity PA, and 10–12 h/day for steps (all p values <0.05). APE increased with shorter wear time (13 h/day=3.9–14.1%; 12 h/day=9.9–15.2%, 11 h/day=17.1–35.5%; 10 h/day=24.6–40.3%). Discussion These data suggest that using accelerometer wear time criteria of 12 h/day or less may underestimate step count and time spent in various PA levels.

Validity and reliability of the global physical activity questionnaire (GPAQ)

There is limited published validity and reliability evidence to support using the Global Physical Activity Questionnaire. Two studies were conducted to evaluate validity and reliability evidence for the Global Physical Activity Questionnaire. In Study 1: 69 adults completed the Global Physical Activity Questionnaire (three months apart; n = 54), International Physical Activity Questionnaire, fitness and anthropometric measures. All participants wore a pedometer and 53 participants wore an accelerometer for seven days at baseline. In Study 2, 16 adults completed the Global Physical Activity Questionnaire 10 days apart. Global Physical Activity Questionnaire moderate and vigorous minutes were correlated with the accelerometer moderate (r = 0.28) and vigorous (r = 0.48) physical activity. The Global Physical Activity Questionnaire and International Physical Activity Questionnaire were related for sedentary behaviors (r = 0.51), moderate-to-vigorous (r = 0.48) and vigorous (r = 0.63) PA. Global Physical Activity Questionnaire moderate-to-vigorous physical activity was associated with percent fat (r = −0.32), estimated VO2 max (r = 0.26), and step count (r = 0.39). The Global Physical Activity Questionnaire demonstrated graded differences across categories for step count, body mass index, waist circumference, percent fat, fitness, and accelerometer measured activity. Short-term test–retest reliability (10 days) ranged from 0.83 to 0.96 while long-term reliability (three months) was 0.53 to 0.83. These data provide low-to-moderate validity and generally acceptable reliability evidence for the Global Physical Activity Questionnaire.

Does increased prescribed exercise alter non-exercise physical activity/energy expenditure in healthy adults? A systematic review

Prescribed physical activity/exercise training may reduce non‐exercise physical activity resulting in no change in total daily energy expenditure and no or minimal exercise‐induced weight loss. This systematic review evaluated cross‐sectional, short‐term (2–14 d), randomized and non‐randomized trials which reported on the effect of prescribed physical activity/exercise on non‐exercise physical activity/energy expenditure in healthy adults. PubMed and Embase were searched (from January 1990 to March 2013) for articles that presented data on the change in non‐exercise physical activity/energy expenditure in response to prescribed physical activity/exercise training. Thirty‐one articles were included in this review. One‐hundred per cent of cross‐sectional studies (n = 4), 90% of short‐term studies (n = 10), 50% of non‐randomized trials (n = 10) and 100% of randomized trials (n = 7) reported no reductions in non‐exercise physical activity/energy expenditure in response to prescribed physical activity/exercise training. We found minimal evidence to support the hypothesis that prescribed physical activity/exercise training results in decreased non‐exercise physical activity/energy expenditure in healthy adults. However, this literature is limited by the lack of adequately powered trials designed specifically to evaluate this hypothesis which have included assessments of both the energy expenditure of prescribed exercise and non‐exercise energy expenditure using state‐of‐the‐art techniques, i.e. indirect calorimetry and doubly labelled water, respectively.

Physical activity and academic achievement across the curriculum (A + PAAC): rationale and design of a 3-year, cluster-randomized trial

BackgroundImproving academic achievement and reducing the rates of obesity in elementary school students are both of considerable interest. Increased physical activity during academic instruction time during school offers a potential intervention to address both issues. A program titled “Physical Activity Across the Curriculum” (PAAC) was developed in which classroom teachers in 22 elementary schools were trained to deliver academic instruction using physical activity with a primary aim of preventing increased BMI. A secondary analysis of data assessed the impact of PAAC on academic achievement using the Weschler Individual Achievement Test-II and significant improvements were shown for reading, math and spelling in students who participated in PAAC. Based on the results from PAAC, an adequately powered trial will be conducted to assess differences in academic achievement between intervention and control schools called, “Academic Achievement and Physical Activity Across the Curriculum (A + PAAC).”Methods/designSeventeen elementary schools were cluster randomized to A + PAAC or control for a 3-year trial. Classroom teachers were trained to deliver academic instruction through moderate-to-vigorous physical activity with a target of 100+ minutes of A + PAAC activities per week. The primary outcome measure is academic achievement measured by the Weschler Individual Achievement Test-III, which was administered at baseline (Fall 2011) and will be repeated in the spring of each year by assessors blinded to condition. Potential mediators of any association between A + PAAC and academic achievement will be examined on the same schedule and include changes in cognitive function, cardiovascular fitness, daily physical activity, BMI, and attention-to-task. An extensive process analysis will be conducted to document the fidelity of the intervention. School and student recruitment/randomization, teacher training, and baseline testing for A + PAAC have been completed. Nine schools were randomized to the intervention and 8 to control. A random sample of students in each school, stratified by gender and grade (A + PAAC = 370, Control = 317), was selected for outcome assessments from those who provided parental consent/child assent. Baseline data by intervention group are presented.DiscussionIf successful, the A + PAAC approach could be easily and inexpensively scaled and disseminated across elementary schools to improve both educational quality and health. Funding source: R01- DK85317. Trial registration: US NIH Clinical Trials, http://NCT01699295.

Aerobic Capacity and Cognitive Control in Elementary School-Age Children

PURPOSE The current study examined the relationship between childrens performance on the Progressive Aerobic Cardiovascular Endurance Run subtest of the FitnessGram® and aspects of cognitive control that are believed to support academic success. METHODS Hierarchical linear regression analyses were conducted on a sample of second- and third-grade children (n = 397) who completed modified versions of a flanker task and spatial n-back task to assess inhibitory control and working memory, respectively. RESULTS Greater aerobic fitness was significantly related to shorter reaction time and superior accuracy during the flanker task, suggesting better inhibitory control and the facilitation of attention in higher-fit children. A similar result was observed for the n-back task such that higher-fit children exhibited more accurate target detection and discrimination performance when working memory demands were increased. CONCLUSIONS These findings support the positive association between aerobic fitness and multiple aspects of cognitive control in a large sample of children, using a widely implemented and reliable field estimate of aerobic capacity. Importantly, the current results suggest that this relationship is consistent across methods used to assess fitness, which may have important implications for extending this research to more representative samples of children in a variety of experimental contexts.

Evaluation of the MyWellness Key accelerometer

Objective To examine the concurrent validity of the Technogym MyWellness Key accelerometer against objective and subjective physical activity (PA) measures. Design Randomised, cross-sectional design with two phases. The laboratory phase compared the MyWellness Key with the ActiGraph GT1M and the Yamax SW200 Digiwalker pedometer during graded treadmill walking, increasing speed each minute. The free-living phase compared the MyWellness Key with the ActiGraph, Digiwalker, Bouchard Activity cord (BAR) and Global Physical Activity Questionnaire (GPAQ) for seven continuous days. Data were analysed using Spearman rank-order correlation coefficients for all comparisons. Setting Laboratory and free-living phases. Participants Sixteen participants randomly stratified from 41 eligible respondents by sex (n=8 men; n=8 women) and PA levels (n=4 low, n=8 middle and n=4 high active). Results There was a strong association between the MyWellness Key and the ActiGraph accelerometer during controlled graded treadmill walking (r=0.91, p<0.01) and in free-living settings (r=0.73–0.76 for light to vigorous PA, respectively, p<0.01). No associations were observed between the MyWellness Key and the BAR and GPAQ (p>0.05). Conclusions The MyWellness Key has a high concurrent validity with the ActiGraph accelerometer to detect PA in both controlled laboratory and free-living settings.

Linear/nonlinear relations of activity and fitness with children's academic achievement.

UNLABELLED A growing research base suggests that the benefits of physical activity (PA) and aerobic fitness for children extend beyond overall health/well-being to include academic achievement (AA). The majority of research studies on relations of PA and fitness with AA have used linear-only analytic approaches, thereby precluding the possibility that PA and fitness could have a differing effect on AA for those more/less active or fit. OBJECTIVE This study aimed to evaluate both linear and nonlinear associations of PA and aerobic fitness with childrens AA among a sample of 687 second and third grade students from 17 Midwest schools. STUDY DESIGN Using baseline data (fall 2011) from a larger 3-yr intervention trial, multilevel regression analyses examined the linear and nonlinear associations of AA with PA and with progressive aerobic cardiovascular endurance run (PACER) laps (i.e., aerobic fitness), controlling for relevant covariates. RESULTS Fitness, but not PA, had a significant quadratic association with both spelling and mathematics achievement. Results indicate that 22-28 laps on the PACER was the point at which the associated increase in achievement per lap plateaued for spelling and mathematics. CONCLUSIONS Increasing fitness could potentially have the greatest effect on childrens AA for those below the 50th fitness percentile on the PACER.