| 1. |
|
|
| 2. |
- Dencker, Magnus, et al.
(författare)
-
Aerobic capacity related to cardiac size in young children.
- 2013
-
Ingår i: Journal of Sports Medicine and Physical Fitness. - 0022-4707. ; 53:1, s. 42-47
-
Tidskriftsartikel (refereegranskat)abstract
- Aim:Aerobic capacity, defined as peak oxygen uptake (VO2PEAK), is generally considered to be the best single marker for aerobic fitness. We assessed if VO2PEAK is related to different cardiac dimensions in healthy young children on a population base. Methods: In a cross-sectional study, 245 children (137 boys and 108 girls) aged 8-11 years, were recruited from a population based cohort. VO2PEAK (ml/min-1/kg-1) was assessed by indirect calorimetry during a maximal exercise test. DXA-scan was used to measure lean body mass (LBM) and total fat mass (TBF). Echocardiography, with 2-dimensional guided M-mode, was performed in accordance with current guidelines. Left ventricular end-diastolic diameter (LVDD) and left atrial end-systolic diameter (LA) were measured, and left ventricular mass (LVM) was calculated. Results: Univariate correlations were found between VO2PEAK versus LVDD r=0.44 and LA r=0.27 (both P<0.05) and LVM r=-0.06 (NS) in boys. Corresponding values for girls were; 0.55, 0.34 (both P<0.05) and 0.11 (NS). Multiple regression analysis with VO2PEAK as dependent variable and inclusion of LBM, TBF, sex, age, Tanner stage, and maximal heart rate as independent variables showed that 67% of the total variance of VO2PEAK could be explained by these variables. Including LVDD or LA in the model, added 1% additional explained variance. Conclusion: Findings from this population based cohort of young healthy children show that multiple cardiac dimensions at rest are related to VO2PEAK. However, the different cardiac dimensions contributed very little to the added explained variance of VO2PEAK.
|
|
| 3. |
|
|
| 4. |
- Dencker, Magnus, et al.
(författare)
-
Daily physical activity related to aerobic fitness and body fat in an urban sample of children.
- 2008
-
Ingår i: Scandinavian Journal of Medicine & Science in Sports. - : Wiley. - 1600-0838 .- 0905-7188. ; 18, s. 728-735
-
Tidskriftsartikel (refereegranskat)abstract
- This study evaluates associations between objectively measured daily physical activity vs aerobic fitness and body fat in children aged 8-11 years. A cross-sectional study of 225 children aged 7.9-11.1 years was performed. Abdominal fat mass (AFM) and total body fat (TBF) were quantified by dual-energy x-ray absorptiometry. TBF was calculated as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF. Aerobic fitness was measured by indirect calorimetry during a maximal cycle ergometer exercise test. Daily physical activity was assessed by accelerometers for 4 days and daily accumulation of moderate-to-vigorous and vigorous activity was calculated. Significant relationships (P<0.05) existed for vigorous activity vs ln BF% (r=-0.40), ln AFM (r=-0.35), TBF/AFM (r=-0.22) and aerobic fitness (r=0.38), whereas moderate-to-vigorous activity displayed weaker relationships (-0.22, -0.18, -0.12 NS, and 0.25). Multiple regression analyses with inclusion of possible confounders concluded that vigorous activity was independently related to aerobic fitness and ln BF% or ln AFM. Moderate-to-vigorous activity was only independently related to aerobic fitness. In this population, low daily accumulation of vigorous activity was, already in children aged 8-11 years, associated with more body fat and lower aerobic fitness. A similar relation was not found for daily accumulation of moderate-to-vigorous activity.
|
|
| 5. |
- Dencker, Magnus, et al.
(författare)
-
Daily physical activity related to body fat in children aged 8-11 years
- 2006
-
Ingår i: Journal of Pediatrics. - : Elsevier BV. - 1097-6833 .- 0022-3476. ; 149:1, s. 38-42
-
Tidskriftsartikel (refereegranskat)abstract
- Objective To evaluate the association between objectively measured daily Study design Cross-sectional, observational, study of 248 children aged 7.9 to 11.1 years. Abdominal fat mass and total body fat mass were measured by dual-energy X-ray absorptiometry. Daily physical activity was assessed by accelerometers for 4 days. Results Total body fat expressed as a percentage of body mass was inversely related to minutes of vigorous physical activity per day, for all children r = -0.38 (P < .05). Children, both boys and girls, in the highest quartile of body fat performed on average 12 minutes less vigorous activity per day compared with their counterparts in the lowest quartile. Multiple regression analysis revealed that independent factors for body fat were number of minutes of vigorous activity per day and sex. Conclusion Low physical activity can be a contributing factor in childhood obesity. Only longitudinal studies, however, can give more definitive information about the relation between daily physical activity and obesity.
|
|
| 6. |
- Dencker, Magnus, et al.
(författare)
-
Objectively measured daily physical activity related to cardiac size in young children.
- 2009
-
Ingår i: Scandinavian Journal of Medicine & Science in Sports. - : Wiley. - 1600-0838 .- 0905-7188. ; Aug 5, s. 664-668
-
Tidskriftsartikel (refereegranskat)abstract
- Training studies in children have suggested that endurance training can give enlargement of cardiac dimensions. This relationship has not been studied on a population-based level in young children with objective methods. A cross-sectional study was made of 248 children (140 boys and 108 girls), aged 8-11 years, from a population-based cohort. Left ventricular end-diastolic diameter (LVDD) and left atrial end-systolic diameter (LA) were measured with echocardiography and indexed for body surface area (BSA). Physical activity was assessed by accelerometry, and the duration of vigorous physical activity per day (VPA) was calculated. Acceptable accelerometer and echocardiography measurements were obtained in 228 children (boys=127, girls=101). Univariate correlations between VPA and LVDD were indexed for BSA in boys (r=0.27, P<0.05) and in girls (r=0.10, NS). Multiple regression analysis showed that independent factors for LVDD, indexed for BSA for boys, were age and VPA. LA indexed for BSA was not related to physical activity variables in either gender. No clear relationship exists between cardiac size and daily physical activity in children aged 8-11 years. This suggests that significant cardiac remodelling due to volume exposure secondary to a high amount of physical activity begins later in life.
|
|
| 7. |
- Ek, Staffan, et al.
(författare)
-
Relative Age Effect of Sport Academy Adolescents, a Physiological Evaluation
- 2020
-
Ingår i: Sports. - Basel : MDPI. - 2075-4663. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- The relationship between birth quarter distribution and physiological characteristics related to athletic skills, in adolescent sport academy students has not been fully investigated. In a cross-sectional study, we recruited 86 boys and 52 girls aged 12-14 years during their first term at a sport academy school. We measured body size, cardiac size, pulmonary function, body composition, lower body power, cardiorespiratory fitness parameters, and running endurance by standard methods and analyzed these estimates in relation to birth quarter by ANOVA. Birth quarter distribution in our cohort was compared with birth quarter distribution in the same ages in the whole of Sweden and analyzed by logistic regression. The academy had an overrepresentation of students born in the first quartile of the year compared to those born in the last quartile (odds ratio 2.3 (95% CI: 1.1-4.7)). When comparing the physiological characteristics between birth quarters, uniformity is prominent since out of 26 performed physiological and anthropometric tests only four showed statistically significant group differences. We thus believe that the selection process to the sport academy favours athletes with higher chronological age, i.e., a so-called relative age effect is present. © 2020 MDPI (Basel, Switzerland).
|
|
| 8. |
- Gudmundsson, P, et al.
(författare)
-
Parametric quantification of myocardial ischaemia using real-time perfusion adenosine stress echocardiography images, with SPECT as reference method.
- 2010
-
Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 30:1, s. 30-42
-
Tidskriftsartikel (refereegranskat)abstract
- Summary Background: Real-time perfusion (RTP) adenosine stress echocardiography (ASE) can be used to visually evaluate myocardial ischaemia. The RTP power modulation technique, provides images for off-line parametric perfusion quantification using Qontrast((R)) software. From replenishment curves, this generates parametric images of peak signal intensity (A), myocardial blood flow velocity (beta) and myocardial blood flow (Axbeta) at rest and stress. This may be a tool for objective myocardial ischaemia evaluation. We assessed myocardial ischaemia by RTP-ASE Qontrast((R))-generated images, using 99mTc-tetrofosmin single-photon emission computed tomography (SPECT) as reference. Methods: Sixty-seven patients admitted to SPECT underwent RTP-ASE (SONOS 5500) during Sonovue((R)) infusion, before and throughout adenosine stress, also used for SPECT. Quantitative off-line analyses of myocardial perfusion by RTP-ASE Qontrast((R))-generated A, beta and Axbeta images, at different time points during rest and stress, were blindly compared to SPECT. Results: We analysed 201 coronary territories [corresponding to the left anterior descendent (LAD), left circumflex (LCx) and right coronary (RCA) arteries] from 67 patients. SPECT showed ischaemia in 18 patients. Receiver operator characteristics and kappa values showed that A, beta and Axbeta image interpretation significantly identified ischaemia in all territories (area under the curve 0.66-0.80, P = 0.001-0.05). Combined A, beta and Axbeta image interpretation gave the best results and the closest agreement was seen in the LAD territory: 89% accuracy; kappa 0.63; P<0.001. Conclusion: Myocardial isachemia can be evaluated in the LAD territory using RTP-ASE Qontrast((R))-generated images, especially by combined A, beta and Axbeta image interpretation. However, the technique needs improvements regarding the LCx and RCA territories.
|
|
| 9. |
- Larsson, Jonas, 1968-, et al.
(författare)
-
Cardiorespiratory responses of load carriage in female and male soldiers
- 2022
-
Ingår i: Applied Ergonomics. - Oxford : Elsevier. - 0003-6870 .- 1872-9126. ; 101
-
Tidskriftsartikel (refereegranskat)abstract
- PurposeTo investigate the effect of sex and load carriage on cardiorespiratory responses to high intensity exercise in male and female soldiers.MethodsSoldiers (9 women, 9 men) performed a graded treadmill test until exhaustion with no load (NL) and combat-gear with body armor (CG). Cohen's d effect sizes, paired t-tests and ANOVA were used to study differences between conditions. A mixed linear regression model analyzed the relationship between heart rate (HR) and oxygen uptake (V̇O2) with load and between sexes.ResultsWearing CG resulted in, for both sexes, a decreased time to exhaustion (−11 min), lower V̇O2peak (L/min) ES = 0.56; VO2peak (mL//kg/min) ES = 2.44, both p < 0.001, a net decrease in minute ventilation (ES = 3.53) and no change in HRmax. No sex-difference were present except for absolute V̇O2peak. The VO2 and HR relationship showed a cardiorespiratory reduction wearing CG vs. NL. Added load was equal between sexes, although female soldiers' CG relative to body mass was higher (25%) than male soldiers’ (20%), p < 0.01.ConclusionWearing CG reduces soldiers’ cardiorespiratory capacity and exercise performance level, although the reduction cannot be explained solely based on the added load of CG, instead CG seems to restrict the capacity to fully ventilate. No sex differences were found in relative cardiorespiratory responses to wearing CG compared to NL.
|
|
| 10. |
- Larsson, Jonas, 1968-, et al.
(författare)
-
Cardiovascular Effects of Load Carriage in Soldiers; A Pilot Study
- 2019
-
Ingår i: Book of Abstracts of the 24th Annual Congress of the European College of Sport Science – 3rd - 6th July 2019, Prague – Czech Republic. - : European College of Sport Science. - 9783981841428 ; , s. 422-423
-
Konferensbidrag (refereegranskat)abstract
- Introduction: Previous studies have shown that risk of physical fatigue increases if prolonged average work intensity exceeds 50% of oxygen uptake (VO2). In order to avoid persistent fatigue in a work setting, it is important to conduct suitable work capacity analyses. In physically demanding jobs where wearing protective gear and/or external load is mandatory, monitoring of cardiovascular demands through heart rate (HR) is one way to track the workers’ relative effort. There are limited studies examining effects of load carrying on cardiovascular capacity where it appears that VO2peak differ when soldiers and firefighters are tested with work-related equipment/clothing compared to light clothing. The aim of this pilot study was to investigate effects of load (combat gear) on HR, VO2 and muscle oxygen saturation (SmO2) compared to no load in soldiers during a graded treadmill protocol.Methods: Eight volunteer army soldiers (1 woman, 7 men) performed a graded treadmill test until exhaustion. All soldiers performed the test twice, once with light clothes and no load (NL) and once with added load, their personal combat gear (CG), with at least 48 h between sessions. The treadmill protocol stages included supine and standing positions, followed by marching speeds of 5.4 km/h and 8 km/h at 0 incline (all 5 min) immediately followed by a set marching speed of 8 km/h with a starting incline of 2 % increasing the incline 2 % every third minute until voluntary exhaustion. Measurements of HR, VO2 and SmO2 were collected continuously and the last 30 s of each stage were averaged and used for statistical analyses (paired t-tests).Results: The mean added load for all soldiers with CG was 16.8 ± 1.1 kg. All soldiers completed at least 6 stages (range 6-11 stages) with both NL and CG, where time to exhaustion with NL was longer (19.1 ± 3.2 min) compared to CG (9.1 ± 2.9 min; p <0.01). Submaximal HR and VO2 were both significantly higher with CG compared to NL (at absolute intensities) at all marching speeds all soldiers completed (5.4 km/h 0 % grade - 8 km/h 4% grade; all p<0.05). For SmO2, marching with CG compared to NL resulted in increased muscle oxygen utilization, at submaximal stages 8 km/h 0% -4% grade (all p<0.05). For values at maximal effort the CG had a significantly lower VO2peak (3.7 ± 0.5 L/min) compared to NL (4.1 ± 0.6 L/min, p <0.01), whereas there was no difference in HRpeak or the lowest value of SmO2 between CG (193.1 ± 7.2 bpm; 42.4 ± 30.3%) and NL (195.4 ± 8.9 bpm; 47.0 ± 29.2%).Conclusions: This pilot study suggests that assessment of aerobic capacity in soldiers should be conducted with combat gear to help determine their actual work capacity during combat and other load carrying tasks. These results suggest that if soldiers’ work performance is determined without added load it overestimates their aerobic capacity (VO2peak) in tasks wearing combat gear, which might lead to added fatigability and deleterious effect on performance.
|
|
