Asgeir Mamen

Effects of a 2-year school-based daily physical activity intervention on cardiorespiratory fitness: the Sogndal school-intervention study

The aim of this study was to describe changes in childrens cardiorespiratory fitness (CRF) following a school‐based physical activity (PA) intervention. In total, 259 children (age 9.3±0.3 years) were invited to participate, of whom 256 participated. The children from the intervention school (63 boys, 62 girls) carried out 60‐min PA over 2 school years. The children from the control school (62 boys, 69 girls) had the regular curriculum‐defined amount of physical education in school, i.e. 45 min twice weekly. One hundred and eighty‐eight children (73.4%) successfully completed both the baseline and the post‐intervention peak oxygen uptake (VO2peak) test. VO2peak was measured directly during a continuous progressive treadmill protocol where the children ran until exhaustion. The children from the intervention school increased their mean VO2peak (95% confidence interval) 3.6 (2.5–4.6) mL/kg/min more than the children from the control school. This VO2peak value was adjusted for both sex and baseline VO2peak. Boys and girls demonstrated similar VO2peak responses. The intervention, primarily carried out at a moderate intensity, had the biggest impact in children with low initial CRF levels. In conclusion, a 2‐year school‐based 60‐min daily PA intervention significantly improved CRF in children.

Effects of a 2-year school-based daily physical activity intervention on cardiovascular disease risk factors: the Sogndal school-intervention study

The aim of this study was to investigate the effect of a 2‐year school‐based physical activity (PA) intervention in 9‐year‐old children on cardiovascular disease (CVD) risk factors. One intervention school (I‐school) (n=125) and one control school (C‐school) (n=131) were included. The children at the I‐school carried out 60 min of PA daily. The PA lessons were planned, organized and led by expert physical education (PE) teachers. In the C‐school, children were offered the normal 45 min of PE twice weekly. The intervention resulted in a greater beneficial development in systolic (P=0.003) and diastolic (P=0.002) blood pressure, total cholesterol‐to‐high‐density lipoprotein cholesterol ratio (P=0.011), triglyceride (P=0.030) and peak oxygen uptake (P<0.001) in I‐school children than in C‐school children. No significant differences were observed in waist circumference, body mass index and the homeostasis model assessment for insulin resistance between the two groups. Furthermore, the intervention, primarily carried out at moderate intensity, had the strongest impact in children with the least favorable starting point. In conclusion, a daily school‐based PA intervention can beneficially modify childrens CVD risk profile if the intervention has sufficient duration and includes a substantial amount of daily PA, and if the PA is implemented by expert PE teachers.

Cardiovascular risk factor clustering and its association with fitness in nine-year-old rural Norwegian children

This paper describes cardiovascular disease (CVD) risk factor levels in a population‐representative sample of healthy, rural Norwegian children and examines the association between fitness and clustering of CVD risk factors. Final analyses included 111 boys and 116 girls (mean age 9.3 ± 0.3). To determine the degree of clustering, six CVD risk factors were selected: homeostasis model assessment score, waist circumference, triglycerides, systolic blood pressure, total cholesterol to high‐density lipoprotein ratio and fitness (VO2peak). Clustering was observed in 9.9% of the boys and 13.8% of the girls. In a different analysis, fitness was omitted as a CVD risk factor and analyzed against the five remaining CVD risk factors. Low fitness was a strong predictor for clustering of CVD risk factors, and children in the least‐fit quartile had significantly poorer CVD risk factor values than all of those in the other quartiles. Finally, subjects were cross‐tabulated into different fat–fit groups. For both sexes, the unfit and overweight/obese group had a significantly higher CVD risk factor score than the fit and normal weight group. Clustering of CVD risk factors was present in this group of rural children. Low fitness, and low fitness and high fatness combined, were highly associated with a clustered CVD risk.

The Andersen Aerobic Fitness Test: reliability and validity in 10-year-old children

Background High aerobic fitness is consistently associated with a favorable metabolic risk profile in children. Direct measurement of peak oxygen consumption (VO2peak) is often not feasible, thus indirect tests such as the Andersen test are required in many settings. The present study seeks to determine the reliability and validity of the Andersen test in 10-year-old children. Methods A total of 118 10-year-old children (67 boys and 51 girls) were recruited from one school and performed four VO2peak tests over three weeks: three Andersen tests (indirect) and one continuous progressive treadmill test (direct). Of these, 104 children provided valid data on all Andersen tests and 103 children also provided valid data on the direct treadmill test. Reliability and validity were assessed using Bland Altman plots and linear regression analysis. Results Bias (mean change) and random error (limits of agreement) were 26.7±125.2 m for test 2 vs. test 1 (p<.001 for mean difference) and 3.9±88.8 m for test 3 vs. test 2 (p = .514 for mean difference). The equation to estimate VO2peak suggested by Andersen et al. (2008) showed a poor fit in the present sample; thus, we suggest a new equation: VO2peak = 23.262+0.050*Andersen distance –3.858*gender –0.376*body weight (R2 = 0.61, standard error of the estimate = 5.69, p<.001, boys = 0, girls = 1). Conclusions The Andersen test provided reliable and valid data on a group level. However, a substantial degree of individual variability was found for estimates of VO2peak. Researchers should be aware of the amount of noise in indirect tests that estimate aerobic fitness.

Cardiorespiratory fitness and body mass index values in 9‐year‐old rural Norwegian children

Aim: To describe cardiorespiratory fitness and body mass index (BMI) values in a representative population of 9‐year‐old Norwegian children in two rural communities and compare present values with previous findings.

Examination of the Moxus Modular Metabolic System by the Douglas-bag technique

The purpose of this study was to examine the performance of the Moxus Modular Metabolic System from AEI Technologies, Inc. using the Douglas-bag method as reference. To achieve this, eight moderately trained subjects cycled for 5 min at constant powers from 50 to 300 W in increments of 50 W. The O₂ uptake was measured simultaneously by both systems during the last minute of each stage. The O₂ uptake reported by the Moxus system was 83 ± 78 mL·min⁻¹ higher (mean ± SD; ≈3%, +62 µmol·s⁻¹, P < 0.001) than that reported by the Douglas-bag method; the bias varied by ≈2% between the subjects. The higher O₂ uptake of the Moxus system was a consequence of 1.4% ± 3.0% higher reported ventilation and 2% ± 3% higher reported O₂ extraction per volume of air breathed. The respiratory exchange ratio (R value) reported by the Moxus system rose proportionally to that of the Douglas-bag method and was 1% ± 2% higher for the range examined (0.75-1.10). Repeated tests of the maximal O₂ uptake showed a variability (coefficient of variation) of 2.5%. The study concluded that measurements by the Moxus system showed some bias and residual variation and, in addition, some systematic differences between the subjects in the O₂ uptake. The R value was reported quite accurately with moderate random error. Although there were some computer software and hardware instability problems that need to be solved, the Moxus system worked quite well and provided data more reliable than those of most commercial instruments.

New examination of the performance of the MetaMax I metabolic analyser with the Douglas-bag technique.

Abstract Purpose. To examine the performance of the MetaMax® I metabolic analyser of Cortex Biophysik, running a recent version of the software (MetaSoft v. 1.11.05), using the Douglas-bag method as reference. Experiments. First, 182 measurements of the maximal O2 uptake on school children were analysed both by a former version of the software (MetaMax Analysis) and by a recent version (MetaSoft). In further experiments, seven grown-up subjects of different fitness levels cycled for 5 min at constant powers between 50 and 350 W while the O2 uptake was measured simultaneously by the MetaMax I and the Douglas-bag method during the last minute of altogether 39 exercises. Results. The calculated maximal O2 uptake of the 182 school children was on average 3% lower when the data were reanalysed by MetaSoft than when analysed by the former version of the software. There was in addition a 2% variation. In further experiments on grown-up subjects the O2 uptake reported by the MetaMax I did not differ from that reported by the Douglas-bag system when data for all subjects were pooled, and the random error was 4%. However, the relationships differed slightly between the subjects (p = 0.005), and consequently the random error within each subject was 2–3%. The respiratory exchange ratio (R-value) reported by the MetaMax I differed systematically from that of the control method. However, a reliable R-value could be calculated from the instruments raw data. Conclusions. Our data suggest that the MetaMax I running MetaSoft reports unbiased values of the O2 uptake and with moderate random error.

Changes in mental distress following individualized physical training in patients suffering from chemical dependence

Abstract Thirty-three individuals suffering from chemical dependence and psychiatric disorders underwent 150–500 h of training over 8–15 months with assistance from dedicated training partners, who motivated them to carry out exercise and controlled the intensity of their workouts. To accurately monitor fitness development, direct measures of maximum oxygen uptake and lactate threshold performance were recorded at the start and end of the project. The participants improved moderately in aerobic power by ~5%, (P =0.02). Furthermore, lactate threshold performance increased by ~12% (P =0.03). All scores of depression, anxiety, social phobia, and general mental distress declined during the project (P≤0.03). However, the results of screening tests for alcoholism and drug abuse did not show any significant change (P≥0.28). With the use of accurate physical tests, it was possible to distinguish between responders and non-responders in terms of improvement in aerobic power. The responders showed reduced mental distress on more measures than the non-responders, although the post-treatment level of distress did not differ significantly between the two groups. Thus, it can be concluded that mastery of training and a feeling of being in a better shape may have positive effects on several aspects of mental health in patients suffering from substance dependence.

Association between perceived present working conditions and demands versus attitude to early retirement among construction workers.

BACKGROUND Early retirement is an increasing problem in the construction industry. There is limited information about causes leading employees to leave working life early. We have compared construction workers present situation with their perception of future demands at work to avoid early retirement. METHODS All 87 employees in a medium-sized Norwegian construction company participated in the study. All were men and answered questionnaires on health and pain, work ability, mechanical exposure, psychosocial conditions, and demands regarding future working conditions. RESULTS Most workers showed good work ability, irrespective of age. Many reported high levels of mechanical exposure at work. The level of musculoskeletal pain was higher in the middle-aged (30-50 year old) age groups and seniors aged over 50 years than among the youngest workers less than 30 years of age. All workers reported that good health was important for continued working. Most workers stated that future work must not be too physically demanding. Many workers reported relatively low job satisfaction; consequently an interesting job was rated as important for continuing work. Good social conditions were a high priority. CONCLUSIONS According to the examined construction workers, good health and reduced levels of mechanical exposure at work are essential to avoid early retirement.

A comparison of two physical ability tests for firefighters

Smoke diving is physically demanding, and firefighters must therefore meet certain minimum physical requirements. The aim of this study was to compare the physiological demands of two fire fitness tests: a test of 8-min treadmill walking approved by the Norwegian Labour Inspection Authority (NLIA) (a laboratory test) and a Canadian test consisting of 10 firefighting specific tasks carried out in sequence (an applied field test). If the Canadian field test is as physically demanding as the NLIA-approved laboratory test, it may be suitable for testing Norwegian firefighters. Twenty-two male professional firefighters were tested on separate days. In both tests, the subjects wore a complete firefighting outfit including a breathing apparatus. The test durations were 8 min (NLIA test) versus approximately 6 min (Canadian test). Neither the peak O2 uptake (VO2) of approximately 45 ml kg − 1 min − 1 nor the blood lactate concentration (BLC) at test termination ( ≈ 9 mmol L − 1) differed between the two tests. Rating of perceived exertion (RPECR-10) was lower for the Canadian test than for the Norwegian test (5.2 ± 1.5 vs. 7.0 ± 2.0, respectively), and the exercise time at a high VO2 was also shorter. In conclusion, the Canadian test appeared to be almost as physically demanding as the NLIA-approved test, having equal peak VO2 and BLC, but shorter time at a high VO2 and shorter duration. It might thus be a suitable alternative to the NLIA test with some modifications. The advantage of the Canadian field test is the inclusion of specific firefighting-like tasks that are not part of the NLIA test. Practitioner summary: The physiological load from two firefighter fitness tests was compared. The demands were found to be similar, but the field test was of a shorter duration. With some modifications, the field test may be sufficiently demanding to be used as a fire fitness test for smoke divers in Norway.