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CRF, MVPA, NEAT, PAEE, and Now Sedentary Time: Will the Pendulum Swing Back Again?

Pedro Hallal and Ulf Ekelund

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Bicycling but not Walking Is Independently Associated With Fasting Insulin in Abdominally Obese Women

Erik Hemmingsson, Ulf Ekelund, and Joanna Udden

Background:

The impact of walking and bicycling on insulin resistance (IR) in women with abdominal obesity is unclear.

Methods:

Pooled analysis of data from a randomized trial on physically active commuting (bicycling + walking vs walking only) in women with abdominal obesity [n = 98; age:47.3 ± 7.6 yrs; waist circumference (WC):103.1 ± 7.8 cm]. Bicycling and walking data were collected during 7 consecutive days by trip meters (Trelock FC-410) and pedometers (Yamax digiwalker SW-200) at baseline, 2, 4, and 6 months. Owing to a skew distribution we analyzed bicycling as a binary dummy variable with a 10 km/week cut-off. Fasting serum insulin and homeostatic model assessment – insulin resistance (HOMA-IR) were assessed at baseline and 6 months, as were body mass index (BMI), WC, and dual x-ray absorptiometry (DXA)-assessed % whole-body fat.

Results:

Increased bicycling by 10 km/wk was associated with reductions in fasting serum insulin at follow-up independent of age, treatment allocation, baseline phenotype, Δ walking, and Δ % body fat (β = −10.9, P = .042), but not HOMA-IR (β = −2.0, P = .13). Increased walking was not associated with fasting serum insulin (P = .33) or HOMA-IR (P = .44) at follow-up, after adjustment for the same covariates and Δ bicycling.

Conclusion:

Increased bicycling but not walking was associated with reduced insulin levels at follow-up. Bicycling may be more effective than walking for reducing insulin levels in abdominally obese women.

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Assessing Physical Activity among Children with Accelerometers Using Different Time Sampling Intervals and Placements

Andreas Nilsson, Ulf Ekelund, Agneta Yngve, and Michael Söström

The aim was to investigate (a) the effect of five different time sampling intervals (epoch settings) on different intensity levels when assessing physical activity with an accelerometer (CSA, WAM 7164), and (b) whether the placement of the monitor (on the hip and back) would affect the outcome. Sixteen children (aged 7 yrs) were monitored for four consecutive days. A significant main epoch effect was found for time spent at very high (p < .01) and high (p < .01) intensity activities. No significant difference between the two placements regarding total amount of physical activity (cnts • min−1) or different intensity levels was observed. In conclusion, different time sampling intervals, but not placement, should be carefully considered when assessing physical activity.

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Are Birth Weight, Early Growth, and Motor Development Determinants of Physical Activity in Children and Youth? A Systematic Review and Meta-Analysis

Guro Pauck Øglund, Maria Hildebrand, and Ulf Ekelund

The purpose of this systematic review was to explore whether birth weight, early growth and motor development act as determinants of physical activity in children and youth.

Methods:

We performed a systematic literature search on the possible early life determinants. A meta-analysis was performed on the association between birthweight and objectively measured physical activity.

Results:

We identified 9 studies examining birth weight, in which none of the studies with objectively measured physical activity observed an association between birth weight and physical activity. The meta-analysis confirmed this result (b=-3.08, 95% CI -10.20, 4.04). The 3 studies examining early growth and physical activity in youth differ in methodology and the results are inconsistent. Two studies suggest an association between earlier motor development and physical activity and sport participation in youth. This was not confirmed in a third study.

Conclusion:

Our meta-analysis suggests that birth weight is not an important determinant of physical activity in youth. Available data does not allow firm conclusions whether early growth and motor development act as determinants of physical activity in youth.

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Validity and Comparability of a Wrist-Worn Accelerometer in Children

Orjan Ekblom, Gisela Nyberg, Elin Ekblom Bak, Ulf Ekelund, and Claude Marcus

Background:

Wrist-worn accelerometers may provide an alternative to hip-worn monitors for assessing physical activity as they are easier to wear and may thus facilitate long-term recordings. The current study aimed at a) assessing the validity of the Actiwatch (wrist-worn) for estimating energy expenditure, b) determining cut-off values for light, moderate, and vigorous activities, c) studying the comparability between the Actiwatch and the Actigraph (hip-worn), and d) assessing reliability.

Methods:

For validity, indirect calorimetry was used as criterion measure. ROC-analyses were applied to identify cut-off values. Comparability was tested by simultaneously wearing of the 2 accelerometers during free-living condition. Reliability was tested in a mechanical shaker.

Results:

All-over correlation between accelerometer output and energy expenditure were found to be 0.80 (P < .001).Based on ROC-analysis, cut-off values for 1.5, 3, and 6 METs were found to be 80, 262, and 406 counts per 15 s, respectively. Energy expenditure estimates differed between the Actiwatch and the Actigraph (P < .05). The intra- and interinstrument coefficient of variation of the Actiwatch ranged between 0.72% and 8.4%.

Conclusion:

The wrist-worn Actiwatch appears to be valid and reliable for estimating energy expenditure and physical activity intensity in children aged 8 to 10 years.

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Comparison of Two Methods of Measuring Physical Activity in South African Older Adults

Tracy L. Kolbe-Alexander, Estelle V. Lambert, Judith Biletnikoff Harkins, and Ulf Ekelund

The aim of this study was to assess the validity and reliability of the Yale Physical Activity Survey (YPAS) and the short version of the International Physical Activity Questionnaire (IPAQ) in older South African adults. The YPAS includes measures of weekly energy expenditure (EE) for housework, yard work, caregiving, exercise, and recreation. The IPAQ measures total time and EE during vigorous and moderate activity, walking, and sitting. The instruments were administered twice for test–retest reliability (men, n = 52, 68 ± 5.4 years, and women, n = 70, 66 ± 5.8 years). Data for criterion validity were obtained from accelerometers. YPAS reliability ranged from r = .44 to.80 for men and r = .59 to .99 for women (p < .0001). IPAQ reliability was lower for men (r = .29 to .76) than for women (r = .46 to .77). Criterion validity of the YPAS was .31 to .54 for men and .26 to .29 for women. The YPAS and short IPAQ had comparable results for reliability and criterion validity.

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Objective and Self-Reported Physical Activity and Risk of Falling Among Community-Dwelling Older Adults From Southern Brazil

Renata M. Bielemann, Ricardo Oliveira, Andréa Dâmaso Bertoldi, Elaine Tomasi, Flávio Fernando Demarco, Maria Cristina Gonzalez, Andrea Wendt Bohm, Soren Brage, and Ulf Ekelund

This study evaluated prospective associations between self-reported and objectively measured physical activity (PA) and risk of falls among older adults. A cohort study started in 2014 with 1,451 community-dwelling older adults living in Pelotas, Brazil. Leisure-time PA was obtained by the International Physical Activity Questionnaire and 7-day raw accelerometer data evaluated for total, light PA, and moderate to vigorous PA. In 2016–2017, participants recorded their falls in the previous 12 months. Around 23% of the 1,161 participants followed-up in 2016–2017 experienced a fall in the last 12 months. Participants who did not spend any time in self-reported leisure-time PA at baseline had on average 34% higher risk of falls, and individuals in the lowest tertile for moderate to vigorous PA had on average 51% higher risk of falls compared to those in the highest tertile. Low levels of self-reported and objectively measured moderate to vigorous PA were related to higher risk of falling among Brazilian older adults.

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Validation of activPAL Defined Sedentary Time and Breaks in Sedentary Time in 4- to 6-Year-Olds

Xanne Janssen, Dylan P. Cliff, John J. Reilly, Trina Hinkley, Rachel A. Jones, Marijka Batterham, Ulf Ekelund, Soren Brage, and Anthony D. Okely

This study examined the classification accuracy of the activPAL, including total time spent sedentary and total number of breaks in sedentary behavior (SB) in 4- to 6-year-old children. Forty children aged 4–6 years (5.3 ± 1.0 years) completed a ~150-min laboratory protocol involving sedentary, light, and moderate- to vigorous-intensity activities. Posture was coded as sit/lie, stand, walk, or other using direct observation. Posture was classified using the activPAL software. Classification accuracy was evaluated using sensitivity, specificity and area under the receiver operating characteristic curve (ROC-AUC). Time spent in each posture and total number of breaks in SB were compared using paired sample t-tests. The activPAL showed good classification accuracy for sitting (ROC-AUC = 0.84) and fair classification accuracy for standing and walking (0.76 and 0.73, respectively). Time spent in sit/lie and stand was overestimated by 5.9% (95% CI = 0.6−11.1%) and 14.8% (11.6−17.9%), respectively; walking was underestimated by 10.0% (−12.9−7.0%). Total number of breaks in SB were significantly overestimated (55 ± 27 over the course of the protocol; p < .01). The activPAL performed well when classifying postures in young children. However, the activPAL has difficulty classifying other postures, such as kneeling. In addition, when predicting time spent in different postures and total number of breaks in SB the activPAL appeared not to be accurate.

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Trajectories of Device-Measured Physical Activity During Early Childhood and Its Determinants: Findings From the 2015 Pelotas (Brazil) Birth Cohort Study

Debora Tornquist, Inácio Crochemore-Silva, Luciana Tornquist, Grégore I. Mielke, Ulf Ekelund, Joseph Murray, and Marlos R. Domingues

Background: The objective was to describe trajectories of physical activity (PA) measured by accelerometry during early childhood and to test associations with sociodemographic, gestational, maternal, and perinatal determinants. Methods: Data from 1798 children from the 2015 Pelotas (Brazil) Birth Cohort were analyzed. PA was measured with wrist accelerometers at 1, 2, and 4 years. PA trajectories were estimated using group-based trajectory modeling, and associations with determinants were tested using Poisson regression with robust variance. Results: Two trajectories were identified: Moderate and high PA, both showing a linear increase in PA in the first years but differing in volume. Girls (prevalence ratio [PR]: 0.91; 95% confidence interval [CI], 0.88–0.94), highly educated mothers (PR: 0.93; 95% CI, 0.88–0.97), and high birth weight children (PR: 0.91; 95% CI, 0.85–0.97) showed less probability of high PA trajectory. Birth order ≥3 (PR: 1.06; 95% CI, 1.01–1.11) was associated with higher likelihood of high PA trajectory. Conclusions: Children showed an increase in PA during the first years, with 2 trajectories that differ in PA levels. Female sex, high maternal schooling, and high birth weight reduced the probability of having a high PA trajectory, while higher birth order increased this probability. These characteristics should be considered when planning PA interventions for children in early childhood.

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Associations of Objectively Measured Physical Activity and Sedentary Time With Arterial Stiffness in Pre-Pubertal Children

Eero A. Haapala, Juuso Väistö, Aapo Veijalainen, Niina Lintu, Petri Wiklund, Kate Westgate, Ulf Ekelund, Virpi Lindi, Soren Brage, and Timo A. Lakka

Purpose:

To investigate the relationships of objectively measured physical activity (PA) and sedentary time (ST) to arterial stiffness in prepubertal children.

Method:

Altogether 136 children (57 boys, 79 girls) aged 6–8-years participated in the study. Stiffness index (SI) was assessed by pulse contour analysis based on photoplethysmography. ST, light PA, moderate PA, and vigorous PA were assessed using combined acceleration and heart rate monitoring. We investigated the associations of ST (<1.5METs) and time spent in intensity level of PA above 2–7METs in min/d with SI using linear regression analysis. We studied the optimal duration and intensity of PA to identify children being in the highest quarter of SI using Receiver Operating Characteristics curves.

Results:

Moderate PA, vigorous PA, and cumulative time spent in PA above 3 (β=–0.279, p = .002), 4 (β =–0.341, P<0.001), 5 (β =–0.349, P<0.001), 6 (β =–0.312, P<0.001), and 7 (β =–0.254, p = .005) METs were inversely associated with SI after adjustment for age, sex, and monitor wear time. The cutoffs for identifying children being in the highest quarter of SI <68 min/d for PA exceeding 5 METs and <26 min/d for PA exceeding 6 METs.

Conclusion:

Lower levels of PA exceeding 3–6 METs were related to higher arterial stiffness in children.