The primary purpose of this investigation was to examine the physiological profile of a National Hockey League (NHL) team over a period of 26 years. All measurements were made at a similar time of year (pre-season) in 703 male (mean age +/- SD = 24 +/- 4 y) hockey players. The data were analyzed across years, between positions (defensemen, forwards, and goaltenders), and between what were deemed successful and non-successful years using a combination of points acquired during the season and play-off success. Most anthropometric (height, mass, and BMI) and physiological parameters (absolute and relative VO2 peak, relative peak 5 s power output, abdominal endurance, and combined grip strength) showed a gradual increase over the 26 year period. Defensemen were taller and heavier, had higher absolute VO2 peak, and had greater combined grip strength than forwards and goaltenders. Forwards were younger and had higher values for relative VO2 peak. Goaltenders were shorter, had less body mass, a higher sum of skinfolds, lower VO2 peak, and better flexibility. The overall pre-season fitness profile was not related to team success. In conclusion, this study revealed that the fitness profile for a professional NHL ice-hockey team exhibited increases in player size and anaerobic and aerobic fitness parameters over a 26 year period that differed by position. However, this evolution of physiological profile did not necessarily translate into team success in this particular NHL franchise.
To evaluate the energy metabolism of peripheral skeletal muscle during exercise in patients with chronic respiratory impairment, the 31P-nuclear magnetic resonance (NMR) spectra of forearm muscle were investigated in nine patients and nine age-matched control subjects. We calculated the phosphocreatine (PCr) to PCr + inorganic phosphate (PI) ratio, the time constant of PCr recovery and the intracellular pH. The exercise consisted of repetitive hand grips against a 2-kg load every 3 s for 6 min (0.33 W). The patients showed a marked decrease in the PCr/(PCr + PI) ratio and pH in the muscle during exercise in contrast to the control subjects whose PCr/(PCr + PI) showed a minor decrease without any change in pH. The relationship between PCr utilization and pH demonstrated that anaerobic glycolysis switched on earlier in patients with chronic respiratory impairment. A split PI peak was observed in five of nine patients during exercise. The PCr/(PCr + PI) ratio during the last minute of exercise correlated significantly with the vital capacity (% predicted), with the FEV1/FVC, with the body weight, with the maximum strength of hand grip, and with the muscle mass. The results indicate impaired oxidative phosphorylation and the early activation of anaerobic glycolysis in the muscles of patients with chronic respiratory impairment. Several factors related to chronic respiratory impairment, such as disuse, malnutrition and dysoxia, would contribute to the metabolic changes observed in the muscles examined.
This study investigated the validity of the Actiheart device for estimating free-living physical activity energy expenditure (PAEE) in adolescents.
Total energy expenditure (TEE) was measured in eighteen Canadian adolescents, aged 15-18 years, by DLW. Physical activity energy expenditure was calculated as 0.9 X TEE minus resting energy expenditure, assuming 10% for the thermic effect of feeding. Participants wore the chest mounted Actiheart device which records simultaneously minute-by-minute acceleration (ACC) and heart rate (HR). Using both children and adult branched equation modeling, derived from laboratory-based activity, PAEE was estimated from the ACC and HR data. Linear regression analyses examined the association between PAEE derived from the Actiheart and DLW method where DLW PAEE served as the dependent variable. Measurement of agreement between the two methods was analyzed using the Bland-Altman procedure.
A nonsignificant association was found between the children derived Actiheart and DLW PAEE values (R = .23, R(2) = .05, p = .36); whereas a significant association was found between the adult derived Actiheart and DLW PAEE values (R = .53, R(2) = .29, p
The activity budgets and daily activity rhythms of Varecia rubra were examined over an annual cycle according to season and reproductive stage. Given the relatively high reproductive costs and patchy food resources of this species, I predicted that V. rubra would 1) travel less and feed more during seasonal resource scarcity in an attempt to maintain energy balance, and 2) show sex differences in activity budgets due to differing reproductive investment. Contrary to the first prediction, V. rubra does not increase feeding time during seasonal food scarcity; rather, females feed for a consistent amount of time in every season, whereas males feed most during the resource-rich, hot dry season. The results are consistent with other predictions: V. rubra travels less in the resource-scarce cold rainy season, and there are some pronounced sex differences, with females feeding more and resting less than males in every season and in every reproductive stage except gestation. However, there are also some provocative similarities between the sexes when activity budgets are examined by reproductive stage. During gestation, female and male activity budgets do not differ and appear geared toward energy accumulation: both sexes feed and rest extensively and travel least during this stage. During lactation, activity budgets are geared toward high energy expenditure: both sexes travel most and in equal measure, and rest least, although it remains the case that females feed more and rest less than males. These similarities between female and male activity budgets appear related to cooperative infant care. The high energetic costs of reproduction in V. rubra females may require that they allot more time to feeding year round, and that their overall activity budget be more directly responsive to seasonal climate change, seasonal food distribution, and reproductive schedules.
Human pregnancy is associated with increased requirements for dietary energy and this increase may be partly offset by reductions in physical activity during gestation. Studies in well-nourished women have shown that the physical activity level (PAL), obtained as the total energy expenditure (TEE) divided by the BMR, decreases in late pregnancy. However, it is not known if this decrease is really caused by reductions in physical activity or if it is the result of decreases in energy expenditure/BMR (the so-called metabolic equivalent, MET) for many activities in late pregnancy. In the present study activity pattern, TEE and BMR were assessed in twenty-three healthy Swedish women before pregnancy as well as in gestational weeks 14 and 32. Activity pattern was assessed using a questionnaire and heart rate recording. TEE was assessed using the doubly labelled water method and BMR was measured by means of indirect calorimetry. When compared to the pre-pregnant value, there was little change in the PAL in gestational week 14 but it was significantly reduced in gestational week 32. Results obtained by means of the questionnaire and by heart rate recording showed that the activity pattern was largely unaffected by pregnancy. The findings support the following conclusion: in a population of well-nourished women where the activity pattern is maintained during pregnancy, the increase in BMR represents approximately the main part of the pregnancy-induced increase in TEE, at least until gestational week 32.
This study examined whether the Trp64Arg mutation in the beta3-adrenergic receptor (beta3AR) and the A-->G mutation in the uncoupling protein-1 (UCP-1) genes have associations with weight loss and subsequent weight maintenance. Seventy-seven obese (body mass index range, 29-46 kg/m2), clinically healthy, premenopausal women were studied. A 12-wk weight reduction by very low calorie diet (VLCD) was followed by a 40-wk weight maintenance phase. The subjects were divided into four groups according to their beta3AR and UCP-1 genotype: no mutation (control; n=37), only Trp64Arg mutation in the beta3AR gene (n=12), only A-->G mutation in the UCP-1 gene (n=23), and both mutations (n=5). Subjects with both mutations had a lower weight reduction during VLCD than the controls [-10.5+/-0.6 (+/-SEM) vs. -14.0+/-0.5 kg; P=0.051, by ANOVA]. During the maintenance phase, weight in subjects with both mutations increased by 5.8+/-1.5 kg, but remained unchanged in the controls (-0.5+/-0.8 kg; P=0.041). The changes in weight in subjects with only one of the mutation were close to the results in the controls. Resting energy expenditure, adjusted for fat mass, fat-free mass, and maximal aerobic power, did not change differently between the groups throughout the study. The results suggest that a combination of the Trp64Arg mutation in the beta3AR and the A-->G mutation in the UCP-1 genes may be associated with faster weight gain after a VLCD.
To investigate the adequacy of food rations to supply energy needs in cold-temperature environments, caloric expenditure and intake and body composition changes were measured in a group of infantrymen during a 10-day field exercise in the Canadian Arctic. Energy expenditure was measured by the doubly labeled water method (n = 10), and caloric intake was measured by complete food intake records (n = 20). Body composition was determined by isotope dilution (n = 10) and bioelectrical impedence analysis (n = 20) on days 0 and 10. Baseline isotopic enrichment shifts due to geographical relocation were also monitored (n = 5). Mean body weight decreased 0.63 +/- 0.83 (SD) kg over the study period (P
To examine the associations of adiposity, dietary restraint and other personal characteristics with energy reporting quality.
Secondary analysis of 230 women and 158 men from the 1997/98 Ontario Food Survey.
Energy reporting quality was estimated by ratios of energy intake (EI) to both basal metabolic rate (BMR) and total energy expenditure (TEE). Multivariate regression analyses were conducted to examine energy reporting quality between two dietary recalls and in relation to body mass index (BMI) with adjustment for potential confounders. Energy reporting quality was explored across categories of age, BMI, income, education, dieting status and food insecurity through analysis of variance (ANOVA).
From the ANOVA, energy reporting quality was associated with BMI group, age category and weight loss for men and women, as well as with education among women (P 0.05). EI:BMR and EI:TEE on the first and second 24-hour recalls were positively related (P
In several seabirds, nutritional state of a nest-bound chick is negatively correlated with the activity of its hypothalamus-pituitary-adrenal (HPA) axis. Increased corticosterone (cort) secretion has been shown to facilitate changes in behavior that allow hungry chicks to obtain more food from parents. However, if parents are not willing/able to buffer their young from temporary food shortages, increased cort secretion could be detrimental to undernourished chicks. In a system where parents are insensitive to chick demands, low benefits and high costs of activation of the HPA-axis in hungry chicks should lead to a disassociation of the nutritional state of the young and the activity of its HPA-axis. We tested this novel hypothesis for the tufted puffin (Fratercula cirrhata), a seabird with intermittent provisioning of a nest-bound semi-precocial chick. We examined the HPA-axis activity of captive chicks exposed to the following: (1) a short-term (24 h) food deprivation; and (2) an array of prolonged (3 weeks) restrictions in feeding regimens. We found that in response to a short-term food deprivation chicks decreased baseline levels of cort and thyroid hormones. In response to prolonged restrictions, food-limited chicks exhibited signs of nutritional deficit: they had lower body mass, endogenous lipid reserves, and thyroid hormone titers compared to chicks fed ad libitum. However, baseline and maximum acute stress-induced levels of cort were also lower in food-restricted chicks compared to those of chicks fed ad libitum. These results support a major prediction of the study hypothesis that puffin chicks suppress HPA-axis activity in response to short- and long-term nutritional deficits. This physiological adaptation may allow a chick to extend its development in the nest, while eluding detrimental effects of chronic cort elevation.
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