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Variability and Stability in Daily Moderate-to-Vigorous Physical Activity among 10 Year Old Children.

Pereira S, Gomes TN, Borges A, Santos D, Souza M, dos Santos FK, Chaves RN, Katzmarzyk PT, Maia JA - Int J Environ Res Public Health (2015)

Bottom Line: Daily MVPA was lower during the weekend (23.6% of boys and 13.6% of girls comply with the recommended 60 min/day of MVPA) compared to weekdays (60.8% and 35.4%, boys and girls, respectively).Normal weight children were more active than obese children and no effect was found for biological maturation.These results highlight the importance of providing opportunities for increasing children's daily MVPA on all days of week, especially on the weekend.

View Article: PubMed Central - PubMed

Affiliation: CIFI2D, Faculty of Sport, University of Porto, Porto 4099-002, Portugal. sara.s.p@hotmail.com.

ABSTRACT
Day-to-day variability and stability of children's physical activity levels across days of the week are not well understood. Our aims were to examine the day-to-day variability of moderate-to-vigorous physical activity (MVPA), to determine factors influencing the day-to-day variability of MVPA and to estimate stability of MVPA in children. The sample comprises 686 Portuguese children (10 years of age). MVPA was assessed with an accelerometer, and BMI was computed from measured height and weight. Daily changes in MVPA and their correlates (gender, BMI, and maturity) were modeled with a multilevel approach, and tracking was calculated using Foulkes & Davies γ. A total of 51.3% of boys and 26.2% of girls achieved 60 min/day of MVPA on average. Daily MVPA was lower during the weekend (23.6% of boys and 13.6% of girls comply with the recommended 60 min/day of MVPA) compared to weekdays (60.8% and 35.4%, boys and girls, respectively). Normal weight children were more active than obese children and no effect was found for biological maturation. Tracking is low in both boys (γ = 0.59 ± 0.01) and girls (γ = 0.56 ± 0.01). Children's MVPA levels during a week are highly unstable. In summary, boys are more active than girls, maturation does not affect their MVPA, and obese children are less likely to meet 60 min/day of MVPA. These results highlight the importance of providing opportunities for increasing children's daily MVPA on all days of week, especially on the weekend.

No MeSH data available.


Related in: MedlinePlus

Observed and modelled daily MVPA changes in boys and girls.
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ijerph-12-09248-f001: Observed and modelled daily MVPA changes in boys and girls.

Mentions: Daily changes in MVPA and their time-invariant correlates (gender, BMI categories, and maturity offset) were modeled within the SuperMix software v.1 [41] using full maximum likelihood estimation techniques. This was done in a three-step approach. Firstly [Model 1 (M1)], to fit the intricacy of daily changes in MVPA, we used a polynomial function of “time” (i.e., day) with increased complexity. The “time metric” was set as follows: 0 = Monday, 1 = Tuesday, 6 = Sunday as shown below in Figure 1. Guided by SuperMix visual graphic capabilities we fitted a series of nested polynomial models till a 3rd degree. Final decisions about the best fitting solution were made according to deviance and corresponding Chi-square changes in nested models of increasing complexity. A more complex model fits better than a previous one if the differences in their respective deviances are statistically significant. This is done by a Chi-square test with degrees of freedom equal to the difference in estimated parameters of both models. Secondly [Model 2 (M2)], we introduced time-invariant correlates [sex: girls are the reference group, BMI categories (normal weight = reference group, overweight and obese), and maturity offset], and all parameters were simultaneously estimated and tested for their significance. Finally [Model 3 (M3)], we included linear trend (days)-by-sex, and quadratic trend (days2)-by-sex interactions. Since a cubic trend (days3)-by-sex interaction did not improve the model, we retained the previous one (M3).


Variability and Stability in Daily Moderate-to-Vigorous Physical Activity among 10 Year Old Children.

Pereira S, Gomes TN, Borges A, Santos D, Souza M, dos Santos FK, Chaves RN, Katzmarzyk PT, Maia JA - Int J Environ Res Public Health (2015)

Observed and modelled daily MVPA changes in boys and girls.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555277&req=5

ijerph-12-09248-f001: Observed and modelled daily MVPA changes in boys and girls.
Mentions: Daily changes in MVPA and their time-invariant correlates (gender, BMI categories, and maturity offset) were modeled within the SuperMix software v.1 [41] using full maximum likelihood estimation techniques. This was done in a three-step approach. Firstly [Model 1 (M1)], to fit the intricacy of daily changes in MVPA, we used a polynomial function of “time” (i.e., day) with increased complexity. The “time metric” was set as follows: 0 = Monday, 1 = Tuesday, 6 = Sunday as shown below in Figure 1. Guided by SuperMix visual graphic capabilities we fitted a series of nested polynomial models till a 3rd degree. Final decisions about the best fitting solution were made according to deviance and corresponding Chi-square changes in nested models of increasing complexity. A more complex model fits better than a previous one if the differences in their respective deviances are statistically significant. This is done by a Chi-square test with degrees of freedom equal to the difference in estimated parameters of both models. Secondly [Model 2 (M2)], we introduced time-invariant correlates [sex: girls are the reference group, BMI categories (normal weight = reference group, overweight and obese), and maturity offset], and all parameters were simultaneously estimated and tested for their significance. Finally [Model 3 (M3)], we included linear trend (days)-by-sex, and quadratic trend (days2)-by-sex interactions. Since a cubic trend (days3)-by-sex interaction did not improve the model, we retained the previous one (M3).

Bottom Line: Daily MVPA was lower during the weekend (23.6% of boys and 13.6% of girls comply with the recommended 60 min/day of MVPA) compared to weekdays (60.8% and 35.4%, boys and girls, respectively).Normal weight children were more active than obese children and no effect was found for biological maturation.These results highlight the importance of providing opportunities for increasing children's daily MVPA on all days of week, especially on the weekend.

View Article: PubMed Central - PubMed

Affiliation: CIFI2D, Faculty of Sport, University of Porto, Porto 4099-002, Portugal. sara.s.p@hotmail.com.

ABSTRACT
Day-to-day variability and stability of children's physical activity levels across days of the week are not well understood. Our aims were to examine the day-to-day variability of moderate-to-vigorous physical activity (MVPA), to determine factors influencing the day-to-day variability of MVPA and to estimate stability of MVPA in children. The sample comprises 686 Portuguese children (10 years of age). MVPA was assessed with an accelerometer, and BMI was computed from measured height and weight. Daily changes in MVPA and their correlates (gender, BMI, and maturity) were modeled with a multilevel approach, and tracking was calculated using Foulkes & Davies γ. A total of 51.3% of boys and 26.2% of girls achieved 60 min/day of MVPA on average. Daily MVPA was lower during the weekend (23.6% of boys and 13.6% of girls comply with the recommended 60 min/day of MVPA) compared to weekdays (60.8% and 35.4%, boys and girls, respectively). Normal weight children were more active than obese children and no effect was found for biological maturation. Tracking is low in both boys (γ = 0.59 ± 0.01) and girls (γ = 0.56 ± 0.01). Children's MVPA levels during a week are highly unstable. In summary, boys are more active than girls, maturation does not affect their MVPA, and obese children are less likely to meet 60 min/day of MVPA. These results highlight the importance of providing opportunities for increasing children's daily MVPA on all days of week, especially on the weekend.

No MeSH data available.


Related in: MedlinePlus