Background: Recess and physical education time continue to diminish, creating a need for additional physical activity opportunities within the school environment. The use of school gardens as a teaching tool in elementary science and math classes has the potential to increase the proportion of time spent active throughout the school day. Methods: Teachers from 4 elementary schools agreed to teach 1 math or science lesson per week in the school garden. Student physical activity time was measured with ActiGraph GT3X accelerometers on 3 garden days and 3 no-garden days at each school. Direct observation was used to quantify the specific garden-related tasks during class. The proportion of time spent active and sedentary was compared on garden and no-garden days. Results: Seventy-four children wore accelerometers, and 75 were observed (86% participation). Children spent a significantly larger proportion of time active on garden days than no-garden days at 3 of the 4 schools. The proportion of time spent sedentary and active differed significantly across the 4 schools. Conclusions: Teaching lessons in the school garden may increase children’s physical activity and decrease sedentary time throughout the school day and may be a strategy to promote both health and learning.
Erika Rees-Punia, Alicia Holloway, David Knauft and Michael D. Schmidt
Verity Cleland, Michael Schmidt, Jo Salmon, Terry Dywer and Alison Venn
We investigated associations of total sedentary behavior (SB) and objectively-measured and self-reported physical activity (PA) with obesity.
Data from 1662 adults (26–36 years) included daily steps, self-reported PA, sitting, and waist circumference. SB and PA were dichotomized at the median, then 2 variables created (SB/self-reported PA; SB/objectively-measured PA) each with 4 categories: low SB/high PA (reference group), high SB/high PA, low SB/low PA, high SB/low PA.
Overall, high SB/low PA was associated with 95 –168% increased obesity odds. Associations were stronger and more consistent for steps than self-reported PA for men (OR 2.68, 95% CI 1.36–5.32 and OR 1.95, 95% CI 1.01–3.79, respectively) and women (OR 2.66, 95% CI 1.58–4.49 and OR 2.00, 95% CI 1.21–3.31, respectively). Among men, obesity was higher when daily steps were low, irrespective of sitting (low SB/low steps OR 2.07, 95% CI 1.03–4.17; high SB/low steps OR 2.68, 95% CI 1.36–5.32).
High sitting and low activity increased obesity odds among adults. Irrespective of sitting, men with low step counts had increased odds of obesity. The findings highlight the importance of engaging in physical activity and limiting sitting.
Au Bich Thuy, Leigh Blizzard, Michael Schmidt, Pham Hung Luc, Costan Magnussen and Terence Dwyer
The Global Physical Activity Questionnaire (GPAQ) was developed as an improvement of the International Physical Activity Questionnaire (IPAQ) for use in cross-cultural settings. This study compared the reliability and validity of GPAQ and IPAQ in Vietnam.
251 adults were randomly selected from a population-based survey (n = 1978) of noncommunicable disease risk factors. GPAQ and IPAQ were administered on 2 occasions. Participants wore pedometers and logged their physical activity (PA) for 7 consecutive days.
Test-retest correlations of GPAQ measurements differed for participants (n = 153) with stable work patterns (work PA r = .43, total PA r = .39) and those (n = 98) with unstable work patterns (work PA r = −0.02, total PA r = −0.05). IPAQ measurements did not differ in this way. GPAQ reliability was poorer for transport (GPAQ r = .25, IPAQ r = .60) and for leisure (GPAQ r = .21, IPAQ r = .45) PA. GPAQ estimates of total PA for participants with stable work patterns were moderately correlated with IPAQ total PA (r = .32), steps per day (r = .39), and PA log (r = .31).
The modifications made when designing GPAQ improved its reliability for persons with stable work patterns, but at the expense of poorer reliability for persons with more variable PA. GPAQ did not have superior validity to IPAQ.
Au Bich Thuy, Leigh Blizzard, Michael Schmidt, Costan Magnussen, Emily Hansen and Terence Dwyer
Pedometer measurement of physical activity (PA) has been shown to be reliable and valid in industrialized populations, but its applicability in economically developing Vietnam remains untested. This study assessed the feasibility, stability and validity of pedometer estimates of PA in Vietnam.
250 adults from a population-based survey were randomly selected to wear Yamax pedometers and record activities for 7 consecutive days. Stability and concurrent validity were assessed using intraclass correlation coefficients (ICC) and Spearman correlation coefficients.
Overall, 97.6% of participants provided at least 1 day of usable recordings, and 76.2% wore pedometers for all 7 days. Only 5.2% of the sample participants were involved in work activities not measurable by pedometer. The number of steps increased with hours of wear. There was no significant difference between weekday and weekend in number of steps, and at least 3 days of recordings were required (ICC of the 3 days of recordings: men 0.96, women 0.97). Steps per hour were moderately correlated (men r = .42, women r = .26) with record estimates of total PA.
It is feasible to use pedometers to estimate PA in Vietnam. The measure should involve at least 3 days of recording irrespective of day of the week.
Erika Rees-Punia, Charles E. Matthews, Ellen M. Evans, Sarah K. Keadle, Rebecca L. Anderson, Jennifer L. Gay, Michael D. Schmidt, Susan M. Gapstur and Alpa V. Patel
This study examined the test-retest reliability and criterion validity of light (LPA), moderate (MPA), vigorous (VPA), and moderate-to-vigorous (MVPA) physical activity survey items in a subset of participants from a large prospective cohort. Participants included 423 women and 290 men aged 31–72 years in the Cancer Prevention Study-3 (CPS-3). Information on physical activity (PA) was collected using two different surveys: one survey which captures all activity performed during a typical 24-hour period in broad categories (24-hour survey), and a more detailed survey focused primarily on leisure-time PA (LTPA survey). One-year reliability was assessed by computing Spearman correlation coefficients between responses from pre- and post-study periods for both surveys. Validity was assessed by comparing survey-estimated PA with accelerometry, seven-day diaries, and a latent variable representing ‘true’ PA estimated through the method of triads. Reliability was considered acceptable for most items on the LTPA survey (range ρ = 0.45–0.92) and the 24-hour survey (range ρ = 0.37–0.61). LPA validity coefficients were higher for the 24-hour survey, while MPA, VPA, and MVPA coefficients were higher for the LTPA survey. Study results suggest that both CPS-3 PA surveys are suitable for ranking or classifying participants in our population according to overall PA category or intensity-specific activity level.
Yolanda Demetriou, Antje Hebestreit, Anne K. Reimers, Annegret Schlund, Claudia Niessner, Steffen Schmidt, Jonas David Finger, Michael Mutz, Klaus Völker, Lutz Vogt, Alexander Woll and Jens Bucksch
Jacqueline Kerr, James F. Sallis, Neville Owen, Ilse De Bourdeaudhuij, Ester Cerin, Takemi Sugiyama, Rodrigo Reis, Olga Sarmiento, Karel Frömel, Josef Mitáš, Jens Troelsen, Lars Breum Christiansen, Duncan Macfarlane, Deborah Salvo, Grant Schofield, Hannah Badland, Francisco Guillen-Grima, Ines Aguinaga-Ontoso, Rachel Davey, Adrian Bauman, Brian Saelens, Chris Riddoch, Barbara Ainsworth, Michael Pratt, Tom Schmidt, Lawrence Frank, Marc Adams, Terry Conway, Kelli Cain, Delfien Van Dyck and Nicole Bracy
National and international strategies to increase physical activity emphasize environmental and policy changes that can have widespread and long-lasting impact. Evidence from multiple countries using comparable methods is required to strengthen the evidence base for such initiatives. Because some environment and policy changes could have generalizable effects and others may depend on each country’s context, only international studies using comparable methods can identify the relevant differences.
Currently 12 countries are participating in the International Physical Activity and the Environment Network (IPEN) study. The IPEN Adult study design involves recruiting adult participants from neighborhoods with wide variations in environmental walkability attributes and socioeconomic status (SES).
Eleven of twelve countries are providing accelerometer data and 11 are providing GIS data. Current projections indicate that 14,119 participants will provide survey data on built environments and physical activity and 7145 are likely to provide objective data on both the independent and dependent variables. Though studies are highly comparable, some adaptations are required based on the local context.
This study was designed to inform evidence-based international and country-specific physical activity policies and interventions to help prevent obesity and other chronic diseases that are high in developed countries and growing rapidly in developing countries.