Physical Activity, Physical Fitness Levels, Daily Energy Intake and Some Eating Habits of 11-Year-Old Children / Fizička aktivnost, razine fizičke kondicije, dnevni unos energije i neke prehrambene navike 11-godišnjaka

Abstract

Abstract
The aim of this study was to analyse the relationships between energy intake, energy expenditure (physical activity), physical fitness, body mass index and certain eating habits (breakfast and snacks after 8 p.m.) of 11-year-old children.
A cluster sample of 72 children (35 boys and 37 girls), aged 11.8 (±0.3) years was used for this purpose. The measurements took place during two weekdays and two weekend days. Physical activity (energy expenditure) was assessed with multiple-sensor body monitors (SenseWear Armband; BodyMedia Inc., Pittsburgh, PA, USA). Energy intake and frequency of breakfast and snacks after 8 p.m. were assessed using a self-report questionnaire (My Pyramid Tracker Tutorial; USDA, Center for Nutrition Policy and Promotion, USA). Physical fitness levels were evaluated according to the results of the tests: sit-ups, bent arm hang, 600 m run and 20 m endurance shuttle-run using the Eurofit protocols and peak VO2, which was measured with a Cosmed K4b2 portable gas analyser. A Pearson correlation coefficient was used to test the correlations between observed variables, and a multivariate analysis of variance was used to test the influence of certain eating habits (breakfast - regular and occasional; snacks after 8 p.m. - occasional and never) on physical fitness according to sex and age. Mann-Whitney test was used to analyse the differences in in the central tendency between boys and girls.
The results show that boys and girls, especially those with increased BMI, reported a one-third lower intake than reported in other studies. Girls were less physically active than boys. In both groups, the physical activity levels were higher during the week than on weekends, but the energy intakes were higher during the weekends. There were no statistically significant correlations between BMI and physical activity levels. BMI was significantly associated with all selected tests of physical fitness except the sit-ups test. The relationship between the frequency of the two observed meals, physical fitness and sex of the children was negligible.
We can conclude that the assessment of energy intake using a self-report questionnaire is problematic in this age group, especially among those with higher BMI. The measurements of physical activity levels showed that children should be more active during weekends.
Key words: BMI; breakfast; energy expenditure; evening snack; lifestyle of children; weekdays; weekends

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Sažetak

Cilj istraživanja bio je analizirati odnos između unosa energije, potrošnje energije, fizičke aktivnosti i razine fizičke spremnosti, indeksa tjelesne mase te nekih prehrambenih navika (doručak i lagani obroci poslije 20.00 sati) kod 11-godišnjaka. 

Načinjen je klaster uzorak od sedamdeset i dvoje djece (35 dječaka i 37 djevojčica) u dobi od 11.8 (±0.3) godina. Mjerenje se održavalo dva radna dana i dva dana vikenda. Potrošnja energije i fizička aktivnost procijenjeni su višesenzornim tjelesnim monitorima (SenseWear Armband; BodyMedia Inc., Pittsburgh, PA, USA). Unos energije i učestalost doručka i laganih obroka poslije 20.00 sati procijenjeni su prema odgovorima sudionika u upitniku (My Pyramid Tracker Tutorial; USDA, Center for Nutrition Policy and Promotion, USA). Razine fizičke spremnosti procjenjivane su prema rezultatima testova: podizanje trupa, izdržaj u visu, trčanje 600 m i izdržljivosti 20 m shuttle-run (korišten je Eurofit protokol), kao i prema rezultatima vršnog VO2 mjerenog prijenosnim sprirometrom Cosmed K4b2. Pearsonov korelacijski koeficijent korišten je kako bi se testirale korelacije među promatranim varijablama, a multivarijantna analiza varijance korištena je kako bi se testirale razlike među grupama prema njihovoj fizičkoj spremnosti, frekvenciji spomenutih obroka i spolu.
Rezultati pokazuju da dječaci i djevojčice, posebno oni s povećanim indeksom tjelesne mase (ITM), imaju za trećinu manji unos nego što je to bilo u prijašnjim analizama. Djevojčice su manje fizički aktivne od dječaka. U obje grupe razine fizičke aktivnosti bile su veće tijekom tjedna nego u vrijeme vikenda, ali unos energije bio je veći u vrijeme vikenda. Statistički značajne korelacije između ITM i razina fizičke aktivnosti nisu uspostavljene. ITM je značajno povezan sa svim spomenutim testovima fizičke spremnosti, osim u slučaju trbušnjaka. Odnos između učestalosti spomenutih obroka, fizičke spremnosti i spola učenika nije bio statistički značajan.
Možemo zaključiti da je procjena unosa energije i samoprocjene učenika u upitniku problematična za navedenu dobnu skupinu, posebno kod djece s povećanim ITM. Mjerenja fizičke aktivnosti ukazala su na to da bi učenici trebali biti aktivniji tijekom vikenda.

Ključne riječi: doručak; ITM; lagani večernji obroci; potrošnja energije; radni dani; vikendi; životni stil djece.