| 1. |
- Armstrong, Neil, et al.
(författare)
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Aerobic fitness and its relationship to sport, exercise training and habitual physical activity during youth
- 2011
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Ingår i: British Journal of Sports Medicine. - : BMJ. - 0306-3674 .- 1473-0480. ; 45:11, s. 849-858
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Forskningsöversikt (refereegranskat)abstract
- Aim To analyse aerobic fitness and its relationship with sport participation, exercise training and habitual physical activity (HPA) during youth. Methods Studies were located through computer searches of Medline, SPORT Discus and personal databases. Systematic reviews of time trends in aerobic fitness/performance, and exercise training and peak oxygen uptake (peak VO(2)) are reported. Results Peak VO(2) increases with age and maturation. Boys' peak VO(2) is higher than girls'. Despite data showing a decrease in performance test estimates of aerobic fitness there is no compelling evidence to suggest that young people have low levels of peak VO(2) or that it is declining over time. The primary time constant of the VO(2) kinetics response to moderate and heavy intensity exercise slows with age and the VO(2) kinetics response to heavy intensity exercise is faster in boys. There is a negative correlation between lactate threshold as a percentage of peak VO(2) and age but differences related to maturation or sex remain to be proven. Young athletes have higher peak VO(2), a faster primary time constant and accumulate less blood lactate at the same relative exercise intensity than their untrained peers. Young people can increase their peak VO(2) through exercise training but a meaningful relationship between aerobic fitness and HPA has not been demonstrated. Conclusions During youth the responses of the components of aerobic fitness vary in relation to age, maturation and sex. Exercise training will enhance aerobic fitness but a relationship between young people's current HPA and aerobic fitness remains to be proven.
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| 2. |
- Ekelund, Ulf, et al.
(författare)
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What proportion of youth are physically active? : Measurement issues, levels and recent time trends
- 2011
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Ingår i: British Journal of Sports Medicine. - : BMJ. - 0306-3674 .- 1473-0480. ; 45:11, s. 859-865
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Forskningsöversikt (refereegranskat)abstract
- Aim The aim of this review is to summarise issues surrounding the measurement of physical activity (PA) by self-report and accelerometry in youth (2-18 years old). Current levels and temporal trends in PA and sport participation and the effect of assessment method on data interpretation will be summarised. Methods Relevant papers were extracted from a computerised literature search of MEDLINE and personal databases. Additional papers were extracted from reference lists of recently published reviews. Results The criterion validity (direct comparison with an objective method) of self-reported instruments is low to moderate, with correlation coefficients generally between 0.3 and 0.4. Self-report instruments overestimate the intensity and duration of PA and sport participation. The interpretation of PA data from accelerometry is a challenge, and specific issues include the definition of intensity thresholds and the influence of age on intensity thresholds. Recent data on self-reported PA in youth suggest that between 30% and 40% are sufficiently active. Prevalence values for sufficiently active youth measured by accelerometry range between 1% and 100%, depending on the intensity thresholds used. Sport participation is likely to contribute to higher levels of PA. The available evidence does not support the notion that PA levels and sport participation in youth have declined in recent decades. Conclusion The number of youth meeting current PA guidelines varies by assessment method and the intensity thresholds used when PA is measured by accelerometry. The available evidence does not firmly support the notion that PA in young people has declined during the last decades. It is unlikely that any self-report method is sufficiently accurate for examining cross-cultural differences and temporal trends in young people's PA and sport participation over time. Surveillance systems therefore need to strive for an international standardisation using objective measurements of PA to complement existing self-report instruments.
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| 3. |
- Frisk, J., et al.
(författare)
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Exercise and smoking habits among Swedish postmenopausal women
- 1997
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Ingår i: British Journal of Sports Medicine. - : BMJ Publishing Group Ltd. - 0306-3674 .- 1473-0480. ; 31:3, s. 217-223
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To assess exercise habits and their relation to smoking habits and social and medical factors in postmenopausal women.Methods: A cross-sectional study with a questionnaire to all 1324 55-56 year old women in Linkoping, Sweden.Results: Response rate was 85%. About a third of the women took part in some kind of quite strenuous exercise for at least one hour a week. About a quarter worked out once a week; fewer did swimming and jogging. One in four women smoked. Women who used hormone replacement therapy, who were not smoking and who had a physically light occupation more often took part in strenuous sports. Women who had been treated for malignancies or with back problems exercised to the same extent as women in the general population.Conclusion: About a third of the post-menopausal women exercised on a regular basis, if exercise involved in getting to and ti om work was not counted. Since regular physical exercise has many health benefits, more women should be encouraged to take part in regular physical exercise. Factors probably associated with level of education and general awareness of the importance of a healthy Lifestyle positively influenced the likelihood of these women to be physically active on a regular basis. A previous malignant disease or current back problems did not prevent women from taking part in exercise on a regular basis.
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| 4. |
- Klasson-Heggebø, L., et al.
(författare)
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Graded associations between cardiorespiratory fitness, fatness, and blood pressure in children and adolescents
- 2006
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Ingår i: British Journal of Sports Medicine. - : BMJ. - 0306-3674 .- 1473-0480. ; 40:1, s. 25-29; discussion 25
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:To measure the graded relation between cardiorespiratory fitness and sum of skinfolds, waist circumference, and blood pressure in children and adolescents participating in the European youth heart study.METHODS:The participants were 4072 children and adolescents (aged 9 and 15) from Denmark, Portugal, Estonia, and Norway. Cardiorespiratory fitness was indirectly determined using a maximal ergometer cycle test. The sum of four skinfolds, waist circumference, and blood pressure were assessed with a standardised protocol. Linear regression analysis was used to test the graded relation between cardiorespiratory fitness and the dependent variables adjusted for pubertal stage, sex, and country.RESULTS:A significant curvilinear graded relation was found between cardiorespiratory fitness and waist circumference and sum of skinfolds (partial r2 for cardiorespiratory fitness was 0.09-0.26 for the different sexes and age groups). Systolic and diastolic blood pressure also showed a curvilinear relation with cardiorespiratory fitness, and fitness explained 2% of the variance in systolic blood pressure. The difference in systolic blood pressure between the least and most fit was 6 mm Hg.CONCLUSION:A curvilinear graded relation was found between cardiorespiratory fitness and waist circumference, sum of skinfolds, and systolic blood pressure. The greatest difference in these health variables was observed between low and moderate fitness levels.
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| 5. |
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| 6. |
- Ortega, Francisco B., et al.
(författare)
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Cardiovascular fitness modifies the associations between physical activity and abdominal adiposity in children and adolescents : The European Youth Heart Study
- 2010
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Ingår i: British Journal of Sports Medicine. - London, United Kingdom : BMJ Publishing Group Ltd. - 0306-3674 .- 1473-0480. ; 44:4, s. 256-262
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To examine the associations between physical activity (PA) and abdominal adiposity, as measured by waist circumference, in children and adolescents, and to test whether cardiovascular fitness (CVF) modifies these associations.Methods: PA components were measured by accelerometry in 1075 individuals aged 9 or 15 years old. CVF was measured by a maximal cycling test. Self-reported maternal educational level, body mass index, children's birth weight and television viewing were used as confounders.Results: Linear regression did not show any association between the PA variables and waist circumference, after controlling for sex, age and height. When stratifying by CVF level (low/high), time spent at vigorous PA was inversely associated with waist circumference (p≤0.05) in the low CVF group. Unexpectedly, in the high CVF group, the PA variables were positively associated with waist circumference (p≤0.05). In both groups, the results were unchanged after controlling for the confounders. CVF was inversely associated with waist circumference, after controlling for all PA variables (p≤0.01) and confounders (p≤0.01).Conclusion: CVF is inversely associated with abdominal adiposity and seems to modify the associations between PA and abdominal adiposity. In low-fit children and adolescents, time spent in vigorous PA seems to be the key component linked to abdominal adiposity. This finding should be considered in further development of lifestyle intervention strategies. The results found in the high-fit group need to be confirmed.
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| 7. |
- Pintsaar, A., et al.
(författare)
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Postural corrections after standardised perturbations of single limb stance : effect of training and orthotic devices in patients with ankle instability.
- 1996
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Ingår i: British Journal of Sports Medicine. - : BMJ Publishing Group Ltd. - 0306-3674 .- 1473-0480. ; 30:2, s. 151-155
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Soccer players with functional instability of the ankle joint have shown impairment of postural control in single limb stance. The aim of this study was to examine the effect of stance perturbation.Methods: A standardised method for the study of postural corrections after perturbation (Equitest) was used. Female soccer players with and without functional instability were examined.Results: The subjects showed a relative change from ankle to hip synergy at medially directed translations of the support surface. This impairment was restored after eight weeks of ankle disk training. The effect of a shoe and brace did not exceed the effect of the shoe alone.Conclusions: Functional instability seems to be related to impaired ability to retain equilibrium in single limb stance by means of ankle corrections. A positive effect of ankle disk training leading to functional restoration was confirmed.
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