Comparison of oxygen consumption of football players in different positions of the game

Background: Football players have different structural and physiological characteristics due to the variety of tasks that lie in this field. The main purpose of this research was to compare oxygen consumption of football players in different positions of the game. Materials and methods: The research method was causal or post-occurrence. So nine halfbacks, seven attackers, three goalkeepers and six defenders were chosen to participate in this research. The Chinese bicycle was used to measure Vo2max. The heart rate was determined by the electronic heart rate. Nolan Margaria-Kalamen test machine was used to measure the anaerobic power of players. Analysis of variance and F test were used to compare the mean of differences. All steps were performed using SPSS 21 at the level of 0.05. Results: There is a significant difference between Vo2max of goalkeepers and halfbacks; between goalkeepers and attacking players; between defenders and attackers. There was a significant difference between the anaerobic capacity of halfbacks and goalkeepers; between attackers and goalkeepers. Conclusion: The position and the duration of activity has a great effect on Vo2max and anaerobic of players. So to increase both characteristics of the players depends on the position of the game. Key words: oxygen consumption, anaerobic consumption, football, positions of the game

Acute effects of epidermal growth factor on Na+, K+-ATPase-dependent oxygen consumption and the amount of the enzyme units in enterocytes isolated from the jejunum of chickens

Enterocytes from jejunum of male White Leghorn chickens aged 14 d and 20 wk were used to investigate the short-term effect of epidermal growth factor (EGF) on total O2 uptake (TO2) and Na+, K+-dependent O2 uptake (OSO2) and intracellular pH (pHi). Total O2 uptake and OSO2 was decreased (P < 0.05) in enterocytes, isolated from both young and adult birds as concentration of EGF increased in the incubation medium from 0 to 100 ng mL−1. The energy required to support Na+, K+-ATPase activity in jejunal enterocytes obtained from 2-wk-old and 20-wk-old birds was 33–37% and 31–34% of total O2 uptake, respectively. No changes were observed in the amount of the maximal binding sites for 3H-ouabain in enterocytes incubated with EGF; the regulation had not caused rapid decrease in the amount of Na+, K+-ATPase units in the basolateral membrane of enterocytes. Epidermal growth factor caused short-term reduction of pHi as did amiloride. Seemingly, an acute action of EGF in chicken enterocytes in vitro is to reduce the activity of a fixed number of Na+, K+-ATPase units in enterocytes by decreasing Na+, H+-antiport-dependent Na+ influx. Key words: Oxygen consumption, enterocytes, Na+, K+-ATPase, ouabain, epidermal growth factor, intracellular pH, chicks

The effect of feed deprivation on gastrointestinal respiration and Na+, K+-ATPase in chicks

In order to investigate the effect of nutrient availability on energy metabolism of the gastrointestinal tract (GIT) of chicks, two experiments were conducted. In exp. 1, jejunal slices from male White Leghorn chicks at 14 d were incubated in salt-based balanced medium (SBM) or complex medium (CM) for 30 min. The total O2 (TO2) and ouabain-sensitive O2 (OSO2) consumption in jejunal slices were significantly decreased in SBM. The results from exp. 1 imply that when the GIT mucosa is subjected to nutrient deprivation, the utilization of oxygen consumption is altered primarily by shifting active Na+ pump activity. Changes in the TO2, OSO2 and amiloride-sensitive O2 (ASO2) uptake in response to feed deprivation in the small intestine of male White Leghorn chicks were investigated in exp. 2. There was little change in TO2, OSO2 and ASO2 per unit of dry matter of the small intestine from birds subjected to fasting, except for a TO2 decrease in the jejunum of 48 h fasted chicks. However, there were significant reductions in TO2, OSO2 and ASO2 in the jejunum when data were expressed per unit DNA. Na+, K+-ATPase-dependent respiration represented 31–37% of TO2 in the avian jejunoileum. Amiloride-sensitive respiration accounted for 10–18% of TO2 in the jejunoileum. The maximal amount of 3Houabain binding sites of jejunal enterocytes was significantly decreased in chicks fasted for 48 h (P < 0.05). Key words: Oxygen consumption, fasting, Na+, K+-ATPase, ouabain, jejunum, ileum, chicks

Kinetic formulation of oxygen consumption and denitrification processes in soil

A kinetic expression for oxygen, nitrate, nitrite and nitrous oxide reduction in soil was developed. The formulation was based on competitive Michaelis-Menten kinetics for a steady microbial population whose respiratory activity was assumed to be constant so that the number of electrons produced per unit of time was constant. Competition among the electron acceptors was characterized by their affinity toward the electron and by their concentration. Several different values for the affinity coefficients were used to simulate the concentration of O2, NO3−, NO2−, N2O and N2 at various times. When relative magnitudes of affinity coefficients were chosen to be 100 000, 1, 100 and 0.1, for O2, NO3−, NO2− and N2O, respectively, the temporal plot of concentration showed that the disappearance of O2 and NO3− was zero order. The accumulation of NO2− was very small and it was rapidly reduced to N2O. The production rate of N2O was nearly zero order but the magnitude of the rate was rather small as opposed to the rate of disappearance of NO3−. The reduction of N2O to N2 took place only after NO3− had almost disappeared. With these competition parameters NO3− was stable in the presence of O2. The reduction of N2O was also very much retarded in the presence of NO3−. NO2− was relatively unstable, even in the presence of O2, and it was further reduced to N2O. With the relative magnitude of the chosen affinity coefficients, the kinetic formulation effectively simulated the "inhibitory" effect of O2 upon the denitrification process, and the "inhibitory" effect of NO3− and NO2− upon the reduction of N2O to N2. Key words: Oxygen consumption, denitrification, kinetics, competition

Reliability and Validity of a Portable Metabolic Measurement System

The purpose of this study was to assess the reliability and validity of a portable metabolic system (TEEM 100) during submaximal and maximal [Formula: see text] exercise using a computer-based metabolic system as the reference system (REF). Between repeated trials of submaximal exercise at three constant loads, differences in ventilation [Formula: see text] and oxygen consumption [Formula: see text] were 0.2 ± 4.9 L∙min−1 and 0.03 ± 0.10 L∙min−1 for REF, and 1.9 ± 0.7 L∙min−1 and 0.00 ± 0.17 L∙min−1 for TEEM 100. Pooled intraclass reliability coefficients for [Formula: see text] and [Formula: see text] calculated from the repeated submaximal trials were r =.89 and r =.94 for REF, and r =.86 and r =.94 for the TEEM 100. Respiratory exchange ratio (RER) measured by the TEEM 100 was significantly higher (p =.01) at only the lowest workload. At [Formula: see text], the TEEM 100 recorded significantly higher values for FeO2 (p =.01) and RER (p <.001). These results suggest that the TEEM 100 provides reliable and valid measurements of [Formula: see text] during submaximal and maximal exercise. Key words: oxygen consumption, indirect calorimetry, portable analysis, exercise, metabolism

Characterization of embryonic oxygen consumption of two broiler chicken lines differing in body fat content

Eggs of two broiler chicken lines differing in body fat content were incubated and oxygen consumption of single embryos was measured on days 14–19 of incubation with an indirect calorimeter. The objectives of this study were to investigate oxygen consumption patterns of the two genetic lines in the late stage of embryonic development (days 14–19) and the relationship between this pattern and body composition of the bird at 8 wk of age. Oxygen consumption for the genetically lean line (LL) was higher (P < 0.05) than that for the genetically fat line (FL) for days 14 and 15 of incubation, while no differences were detectable after day 16 of incubation. The average oxygen consumption over the 6 d of measurement tended to be higher (P = 0.09) for LL than for FL. Furthermore, male embryos had a higher (P < 0.05) O2 consumption rate after day 17 of incubation than female embryos. The average O2 consumption rate over the 6 d of measurement tended to be higher (P = 0.07) for males than for females across genetic lines. At 8 wk of age, FL birds had greater (P < 0.01) body fat content than LL birds. Also, females showed a greater body fat content than males. Statistical analysis indicated that body fat content and body weight at 8-wk of age were correlated with embryonic O2 consumption. However, the correlation between body weight and embryonic O2 consumption was higher than that between body fat content and embryonic O2 consumption, which would be expected since oxygen consumption reflects lean body mass. Key words: Oxygen consumption, embryo, broiler, fat content, indirect calorimetry