| 1. |
- Ekelund, Ulf, 1960-, et al.
(författare)
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Body movement and physical activity energy expenditure in children and adolescents : how to adjust for differences in body size and age
- 2004
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 79:5, s. 851-856
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Physical activity data in children and adolescents who differ in body size and age are influenced by whether physical activity is expressed in terms of body movement or energy expenditure.OBJECTIVE: We examined whether physical activity expressed as body movement (ie, accelerometer counts) differs from physical activity energy expenditure (PAEE) as a function of body size and age.DESIGN: This was a cross-sectional study in children [n = 26; (+/-SD) age: 9.6 +/- 0.3 y] and adolescents (n = 25; age: 17.6 +/- 1.5 y) in which body movement and total energy expenditure (TEE) were simultaneously measured with the use of accelerometry and the doubly labeled water method, respectively. PAEE was expressed as 1) unadjusted PAEE [TEE minus resting energy expenditure (REE); in MJ/d], 2) PAEE adjusted for body weight (BW) (PAEE. kg(-1). d(-1)), 3) PAEE adjusted for fat-free mass (FFM) (PAEE. kg FFM(-1). d(-1)), and 4) the physical activity level (PAL = TEE/REE).RESULTS: Body movement was significantly higher (P = 0.03) in children than in adolescents. Similarly, when PAEE was normalized for differences in BW or FFM, it was significantly higher in children than in adolescents (P = 0.03). In contrast, unadjusted PAEE and PAL were significantly higher in adolescents (P < 0.01).CONCLUSIONS: PAEE should be normalized for BW or FFM for comparison of physical activity between children and adolescents who differ in body size and age. Adjusting PAEE for FFM removes the confounding effect of sex, and therefore FFM may be the most appropriate body-composition variable for normalization of PAEE. Unadjusted PAEE and PAL depend on body size.
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| 2. |
- Ekelund, Ulf, 1960-, et al.
(författare)
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Energy expenditure assessed by heart rate and doubly labeled water in young athletes
- 2002
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Ingår i: Medicine & Science in Sports & Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 34:8, s. 1360-1366
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To compare total energy expenditure (TEE) estimated by the FLEX heart rate (HR) method with that measured by the doubly labeled water (DLW) technique in young speed skaters. We hypothesized that the accuracy of FLEX HR-estimated TEE would be affected by a) the definition of the FLEX HR and b) the type of training regimen.METHODS: Eight young athletes (mean age 18.2 +/- 1.3 yr) underwent measurements during two 10-d training periods: an off-season period with voluntary training (predominantly running) and a preseason period mainly focused on skating technique training. TEE was measured simultaneously by the DLW and FLEX HR methods. FLEX HR1 was defined as the mean of the HRs during all resting calibration activities and the lowest HR during exercising calibration activities. FLEX HR2 was defined as the mean of the highest HR during resting activities and the lowest HR during exercising.RESULTS: ANOVA showed that FLEX HR1 was significantly lower than FLEX HR2 (mean of both periods; 77 +/- 5 vs 84 +/- 6 beats.min(-1); P = 0.004). TEE values obtained by DLW were 16.8 +/- 3.8 and 16.9 +/- 2.9 MJ.d(-1) in the two periods, respectively. TEE values calculated from FLEX HR1 were 17.8 +/- 3.6 and 17.4 +/- 2.6 MJ.d(-1), and those from FLEX HR2 17.1 +/- 3.1 and 17.0 +/- 2.7 MJ.d-1, respectively. No significant period (P = 0.83) or method (P = 0.44) effect on TEE was observed.CONCLUSION: FLEX HR-estimated TEE was not affected by the definition of the FLEX HR or by the type of training regimen as compared with TEE measured by the DLW method in young athletes.
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| 3. |
- Ekelund, Ulf, 1960-, et al.
(författare)
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Field evaluation of the Computer Science and Application's Inc. Activity monitor during running and skating training in adolescent athletes
- 2000
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Ingår i: International Journal of Sports Medicine. - : Georg Thieme Verlag KG. - 0172-4622 .- 1439-3964. ; 21:8, s. 586-592
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the validity of the CSA activity monitor for assessment of the total amount of physical activity in adolescent athletes. Activity data were compared to data on daily energy expenditure and its derivatives measured by the doubly labeled water method. Seven athletes (speed skaters) with a mean age of 18.2+/-1.1 y were monitored twice (off-season and pre-season) by the activity monitor for eight consecutive days. The primary training during the off-season period was running whereas the pre-season period mainly involved skate training (i.e. inline skating, slideboard training, and skating imitations). Activity counts were significantly correlated to all energy estimates during the off-season period (r=0.93-0.96; P<0.01) whereas not during the pre-season period (r=0.32-0.57). A two-way multivariate analysis of variance showed a significant period effect for activity counts (668+/-163 vs. 548+/-91; P=0.026) whereas not for total daily energy expenditure (15.7+/-2.1 MJ x d(-1) vs. 16.0+/-1.0 MJ x d(-1); P=0.71). The relationship between activity counts and total daily energy expenditure seems to be affected by different training conditions. Therefore these circumstances have to be carefully considered in the interpretation of activity monitor data.
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| 4. |
- Ekelund, Ulf, 1960-, et al.
(författare)
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Physical activity assessed by activity monitor and doubly labeled water in children
- 2001
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Ingår i: Medicine & Science in Sports & Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 33:2, s. 275-281
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To validate the Computer Science and Application's (CSA) activity monitor for assessment of the total amount of physical activity during two school-weeks in 9-yr-old children and to develop equations to predict total energy expenditure (TEE) and activity energy expenditure (AEE) from activity counts and anthropometric variables.METHODS: A total of 26 children (15 boys and 11 girls, mean age 9.1 +/- 0.3 yr) were monitored for 14 consecutive days. TEE was simultaneously measured by the doubly labeled water method. Averaged activity counts (counts.min(-1)) were compared with data on: 1) TEE, 2) AEE = TEE minus basal metabolic rate (BMR; estimated from predictive equations), and 3) daily physical activity level (PAL = TEE/BMR).RESULTS: Physical activity determined by activity counts was significantly related to the data on energy expenditures: TEE (r = 0.39; P < 0.05), AEE (r = 0.54; P < 0.01), and PAL (r = 0.58; P < 0.01). Multiple stepwise regression analysis showed that TEE was significantly influenced by gender, body composition (body weight or fat free mass), and activity counts (R(2) = 0.54--0.60). AEE was significantly influenced by activity counts and gender (R(2) = 0.45). There were no significant differences between activity counts and PAL in discriminating among activity levels with "low" (PAL < 1.56), "moderate" (1.57 < or = PAL > or = 1.81), and "high" (PAL > 1.81) intensity.CONCLUSION: Activity counts from the CSA activity monitor seems to be a useful measure of the total amount of physical activity in 9-yr-old children. Activity counts contributed significantly to the explained variation in TEE and was the best predictor of AEE.
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| 5. |
- Ekelund, Ulf, 1960-, et al.
(författare)
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Physical activity but not energy expenditure is reduced in obese adolescents : a case-control study
- 2002
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 76:5, s. 935-941
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The influence of physical activity on body weight in children and adolescents is controversial.OBJECTIVE: The objective was to test the hypothesis that the intensity and duration of physical activity differ between obese and normal-weight adolescents, with no difference in estimated energy expenditure.DESIGN: We compared physical activity in 18 (8 males, 10 females) obese [body mass index (in kg/m(2)) > 30] adolescents (14-19 y) with that in a matched, normal-weight (BMI < 27) control group. Total energy expenditure (TEE) was measured with the doubly labeled water method, and physical activity was measured simultaneously by accelerometry. The physical activity level was determined as the ratio of TEE to the resting metabolic rate (RMR) and activity energy expenditure as 0.9 TEE minus RMR. Accelerometry data included total physical activity (counts x min(-1) x d(-1)), accumulated and continuous duration of activity, and continuous 10-min periods of physical activity of moderate intensity.RESULTS: There was no significant difference in adjusted (analysis of covariance) TEE, RMR, or AEE between groups. The physical activity level was significantly lower (P < 0.05) in the obese group. No sex x group interaction was observed. Differences in total physical activity (P < 0.001), accumulated time (P < 0.05), continuous time (P < 0.01), and continuous 10-min periods of physical activity of moderate intensity (P < 0.01) were observed between groups.CONCLUSIONS: Obese adolescents are less physically active than are normal-weight adolescents, but physical activity-related energy expenditure is not significantly different between groups. The data suggest that physical activity is not necessarily equivalent to the energy costs of activity.
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| 6. |
- Larsson, Christel, 1972-, et al.
(författare)
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Validity of reported energy expenditure and energy and protein intakes of Swedish vegan and omnivore adolescents
- 2002
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Ingår i: American Journal of Clinical Nutrition. - Bethesda : American society of clinical nutrition. - 0002-9165 .- 1938-3207. ; 75:2, s. 268-274
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Tidskriftsartikel (refereegranskat)abstract
- Background: It is difficult to obtain accurate reports of dietary intake; therefore, reported dietary intakes must be validated. Researchers need low-cost methods of estimating energy expenditure to validate reports of energy intake in groups with different lifestyles and eating habits.Objective: We sought to validate the reported energy expenditure and energy and protein intakes of Swedish adolescent vegans and omnivores.Design: We compared 16 vegans (7 females and 9 males; mean age: 17.4 ± 0.8 y) with 16 omnivores matched for sex, age, and height. Energy expenditure as reported in a physical activity interview and energy and protein intakes as reported by diet history were validated by using the doubly labeled water method and by measuring urinary nitrogen excretion.Results: The validity of reported energy expenditure and energy and protein intakes was not significantly different between vegans and omnivores. The physical activity interview had a bias toward underestimating energy expenditure by 1.4 ± 2.6 MJ/d (95% CI: 2.4, 0.5 MJ/d). The diet-history interview had a bias toward underestimating energy intake by 1.9 ± 2.7 MJ/d (95% CI: 2.9, 1.0 MJ/d) but showed good agreement with the validation method for nitrogen (protein) intake (underestimate of 0.40 ± 1.90 g N/d; 95% CI: 1.10, 0.29 g N/d).Conclusions: The physical activity and diet-history interviews underestimated energy expenditure and energy intake, respectively. Energy intake and expenditure were underestimated to the same extent, and the degree of underestimation was not significantly different between vegans and omnivores. Valid protein intakes were obtained with the diet-history method for both vegans and omnivores.
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