The purpose was to describe the patterns of commuting to school in young people and to examine its associations with physical activity (PA) and cardiorespiratory fitness.
The sample comprised 2271 Estonian and Swedish children and adolescents (1218 females) aged 9-10 years and 15-16 years. Data were collected in 1998/99. Mode of commuting to and from school was assessed by questionnaire. Time spent (min/day) in PA and average PA (counts/min) was measured by accelerometry. Cardiorespiratory fitness was assessed by means of a maximal cycle ergometer test.
Sixty-one percent of the participants reported active commuting to school (ACS). Estonian youth showed lower levels of ACS than Swedish (odds ratio, 0.64; 95% confidence interval, 0.53-0.76) and girls reported lower levels than boys (0.74; 0.62-0.88). ACS boys showed higher PA levels than non-ACS boys for moderate, vigorous, MVPA, and average PA levels (all p = 0.01). Participants who cycled to school had higher cardiorespiratory fitness than walkers or passive travellers (p
The objective of this cross-sectional study was to study associations between low back pain (LBP) and modes of transport to school and leisure activities among adolescents. The study population included all adolescents in eighth and ninth grade in two geographic areas in eastern Norway. Eighty-eight adolescents participated (mean age 14.7 years), making the response rate 84%. Data concerning active (walking/bicycling) and passive (bus/car) journeys were obtained from lists and maps from local authorities, and from the pupils, using a questionnaire that also included LBP, activities and wellbeing. Distance walked/bicycled to school was slightly shorter among those reporting LBP in bivariate analyses. Walking/bicycling more than 8 km weekly to regular activities was inversely associated with LBP in multivariate analysis (OR 0.3; 95% confidence interval 0.1-1.0). No associations were found between passive journeys and LBP. The results raise the question for future research of whether lack of active transport may be one cause behind the increase in juvenile LBP.
Self-efficacy has been found to be an important precondition for behavioral change in sedentary people. The current study examined the effectiveness and added value of including a 15-minute self-efficacy coaching at the start of a 12-week lifestyle physical activity (PA) program.
Participants were randomly assigned to a standard-intervention group (without additional self-efficacy coaching, N = 116) or extra-intervention group (with additional self-efficacy coaching, N = 111). Body mass index (BMI), cardiovascular fitness, self-reported PA, and self-efficacy beliefs were assessed at baseline and immediately after the intervention period. Perceived adherence to the PA program was assessed postintervention.
At posttest, a significant increase in cardiovascular fitness and decrease in BMI were found in both groups. Significant intervention effects emerged on PA behavior, self-efficacy, and program adherence, in favor of the extra-intervention group. Self-efficacy mediated the intervention effect on program adherence whereas no evidence was found for its role as mediator of PA change.
Adding a 15-minute self-efficacy coaching at the start of a lifestyle PA program is a promising strategy to enhance the intervention effects on PA behavior, self-efficacy beliefs, and program adherence. However, the role of self-efficacy as mediator of the intervention effect on in PA was not fully supported.
The present study examined whether activity energy expenditure related to body mass (AEE/kg) is associated with maximal aerobic fitness (VO(2max)), energy balance, and body mass index (BMI) during the 2 hardest weeks of the military basic training season (BT). An additional purpose was to study the accuracy of the pre-filled food diary energy intake. Energy expenditure (EE) with doubly labeled water, energy intake (EI), energy balance, and mis-recording was measured from 24 male conscripts with varying VO(2max). AEE/kg was calculated as (EE x 0.9-measured basal metabolic rate)/body mass. The reported EI was lower (P
Musculoskeletal disorders (MSDs) are the main reason for morbidity during military training. MSDs commonly result in functional impairment leading to premature discharge from military service and disabilities requiring long-term rehabilitation. The purpose of the study was to examine associations between various risk factors and MSDs with special attention to the physical fitness of the conscripts.
Two successive cohorts of 18 to 28-year-old male conscripts (N = 944, median age 19) were followed for six months. MSDs, including overuse and acute injuries, treated at the garrison clinic were identified and analysed. Associations between MSDs and risk factors were examined by multivariate Cox's proportional hazard models.
During the six-month follow-up of two successive cohorts there were 1629 MSDs and 2879 health clinic visits due to MSDs in 944 persons. The event-based incidence rate for MSD was 10.5 (95% confidence interval (CI): 10.0-11.1) per 1000 person-days. Most MSDs were in the lower extremities (65%) followed by the back (18%). The strongest baseline factors associated with MSDs were poor result in the combined outcome of a 12-minute running test and back lift test (hazard ratio (HR) 2.9; 95% CI: 1.9-4.6), high waist circumference (HR 1.7; 95% CI: 1.3-2.2), high body mass index (HR 1.8; 95% CI: 1.3-2.4), poor result in a 12-minute running test (HR 1.6; 95% CI: 1.2-2.2), earlier musculoskeletal symptoms (HR 1.7; 95% CI: 1.3-2.1) and poor school success (educational level and grades combined; HR 2.0; 95% CI: 1.3-3.0). In addition, risk factors of long-term MSDs (>or=10 service days lost due to one or several MSDs) were analysed: poor result in a 12-minute running test, earlier musculoskeletal symptoms, high waist circumference, high body mass index, not belonging to a sports club and poor result in the combined outcome of the 12-minute running test and standing long jump test were strongly associated with long-term MSDs.
The majority of the observed risk factors are modifiable and favourable for future interventions. An appropriate intervention based on the present study would improve both aerobic and muscular fitness prior to conscript training. Attention to appropriate waist circumference and body mass index would strengthen the intervention. Effective results from well-planned randomised controlled studies are needed before initiating large-scale prevention programmes in a military environment.
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To assess the impact of an active school model on children's physical activity (PA).
16-month cluster randomised controlled trial.
10 elementary schools in Greater Vancouver, BC.
515 children aged 9-11 years.
Action Schools! BC (AS! BC) is an active school model that provided schools with training and resources to increase children's PA. Schools implemented AS! BC with support from either external liaisons (liaison schools, LS; four schools) or internal champions (champion schools, CS; three schools). Outcomes were compared with usual practice (UP) schools (three schools).
PA was measured four times during the study using pedometers (step count, steps/day).
Boys in the LS group took 1175 more steps per day, on average, than boys in the UP group (95% CI: 97 to 2253). Boys in the CS group also tended to have a higher step count than boys in the UP group (+804 steps/day; 95% CI: -341 to 1949). There was no difference in girls' step counts across groups.
The positive effect of the AS! BC model on boys' PA is important in light of the current global trend of decreased PA.
We investigated the association between estimated aerobic fitness and cardiovascular risk factors, and how the association is affected by abdominal obesity.
Cross-sectional population study.
Participants comprised 3820 adults aged 25 to 64 years from the FINRISK 2002 Study in Finland. Aerobic fitness was estimated using a non-exercise test. Waist-to-hip ratio (WHR), blood pressure, total cholesterol, high-density lipoprotein cholesterol (HDL-C), triglycerides, HDL-C to total cholesterol ratio, and gamma-glutamyl transferase (GGT) levels were measured by standardized methods.
After controlling for age, smoking and alcohol consumption, aerobic fitness was inversely associated with systolic (P=0.027) and diastolic (P
Physical activity is associated with a reduced risk of all-cause and colonic cancers, and it seems to exert a weaker effect on the risk of breast, lung and reproductive tract tumours. This review examines possible mechanisms behind the observed associations. Restriction of physical activity by pre-existing disease may contribute to the association with lung cancers, but seems a less likely explanation for other types of tumour. Indirect associations through activity-related differences in body build or susceptibility to trauma seem of minor importance. Potential dietary influences include overall energy balance and energy expenditure, the intake and/or bioavailability of minerals, antioxidant vitamins and fibre, and the relative proportions of protein and fat ingested. Links between regular exercise and other facets of lifestyle that influence cancer risks are not very strong, although endurance athletes are not usually smokers, and regular leisure activity is associated with a high socioeconomic status which tends to reduce exposure to airborne carcinogens, both at work and at home. Overall susceptibility to cancer shows a 'U'-shaped relationship to body mass index (mass/height2) reflecting, in part, the adverse influences of cigarette smoking and a tall body build for those with low body mass indices and, in part, the adverse effect of obesity at the opposite end of the body mass index distribution. Obesity seems a major component in the exercise-cancer relationship, with a particular influence on reproductive tract tumours; it alters the pathways of estradiol metabolism, decreases estradiol binding and facilitates the synthesis of estrogens. Among the hormonal influences on cancer risk, insulin-like growth factors promote tumour development and exercise-mediated increases in cortisol and prostaglandin levels may depress cellular components of immune function. However, the most important change is probably the suppression of the gonadotropic axis. Apparent gender differences in the benefits associated with regular exercise reflect gender differences in the hormonal milieu and also a failure to adapt activity questionnaires to traditional patterns of physical activity in females. The immune system is active at various stages of tumour initiation, growth and metastasis. However, acute and chronic changes in immune response induced by moderate exercise are rather small, and their practical importance remains debatable. At present, the oncologist is confronted by a plethora of interesting hypotheses, and further research is needed to decide which are of practical importance.
BACKGROUND: More and better data are needed to understand the action of physical activity (PA) on insulin resistance and the concomitant relation with body fat in adolescence. OBJECTIVE: We examined the relation between total PA and intensity levels with insulin resistance under special consideration of waist circumference and skinfold thickness. DESIGN: This was a cross-sectional study of 613 adolescents (352 girls, 261 boys) with a mean (+/-SD) age of 15.5 +/- 0.5 y from Sweden and Estonia. Total, low, moderate, and vigorous PA was measured by accelerometry. Body fat estimators included waist circumference and the sum of 5 skinfold thicknesses. Fasting insulin and glucose were measured, and insulin resistance was calculated according to the homeostasis model assessment (HOMA). Linear regression analysis and analysis of covariance were used to determine the association between PA and insulin resistance while considering body fat. All estimates were adjusted for sex, country, pubertal status, and indicators of body fat when applicable. RESULTS: Total, moderate, and vigorous PA were inversely correlated with HOMA. Body fat estimators were positively correlated with HOMA. Significant contrasts in HOMA concentrations were seen when comparing the lower 2 tertiles with the upper tertile of PA indicators. Repeating the analysis with body fat estimators showed significant contrasts in HOMA concentrations when comparing the lower tertiles with the upper tertile. CONCLUSION: In view of an increase in obesity in young people, the results accentuate the role of PA in sustaining metabolic balance in adolescence and the potential benefit of an increase of time spent at higher PA levels for youth with relatively elevated amounts of body fat.
This study evaluated the blood lactate concentration ([LA-]) response to the Canadian Aerobic Fitness Test (CAFT) in female subjects and compared the strength of prediction of VO2max determined by [LA-] and heart rate (HR). The sample was composed of 98 Canadian Forces females between the ages of 18 and 45 years. The [LA-] after each stage of the step-test was measured in all subjects by sampling blood from the fingertip. VO2max was measured directly during a maximal treadmill run in 66 of these subjects. The results showed that increasing stages of the step-test were associated with increasing [LA-]. The correlation between [LA-] after Stage 5 of the step-test and the directly determined VO2max was r = -0.72 and did not differ significantly from the correlation between HR and VO2max (r = -0.66). The relationship between [LA-] and VO2max for these females was similar to the one established earlier for males; however, the correlation between HR and VO2max for females was different from that observed in males. The present data for the females suggest that [LA-] and HR after Stage 5 of the CAFT predict VO2max equally well for females under age 40.