Biomedical subjects

B Ekblom

Publications and source records attributed to B Ekblom.

147 records · Page 9Linked to original sources

PubMedDate not supplied

Applied physiology of soccer.

Soccer is characterised as a high intensity, intermittent non-continuous exercise. Players cover approximately 10 km of ground per game, of which 8 to 18% is at the highest individual speed. In higher levels of competition there is a greater number of tackles and headings plus a greater percentage of the game is performed at maximum speed. The average aerobic energy yield during a national level game is around 80% of the individual maximum. Blood lactate concentration during a game averages 7 to 8 mmol/L. Because of a high energy yield most players have empty muscle glycogen stores at the end of the game, were hypohydrated and also have an increased body temperature. Soccer players of national and international standard have a maximal aerobic power of around 60 to 65 ml/kg/min, an above average anaerobic alactacid power, and a greater buffer capacity and muscle strength compared with untrained controls, yet seem to be less flexible.

Aerobiosis↗

PubMedDate not supplied

Mental alertness in response to hypoglycaemia in normal man: the effect of 12 hours and 72 hours of fasting.

To study the influence of hypoglycaemia and starvation on mental functions eight healthy male students age 25-34 years with an ideal body mass of 99.9% +/- 2.5% (mean +/- SEM) were recruited. Hypoglycaemia was induced in random order by an insulin-glucose clamp technique (insulin: 2.4 mU/kg/min + glucose at variable rate) keeping the venous blood glucose at 2.2 mmol/l both after an overnight fast and after 72 h fasting. Mental alertness was assessed by measuring the recognition time, moving time and total reaction time to a visual signal and by a verbal mental clearness test and a synonym learning test during normo- as well as hypoglycaemia. Hypoglycaemia prolonged the total reaction time (p less than 0.05) and the time required for the mental clearness test (p less than 0.05). Compared with a control study performed at normoglycaemia the learning effect of the synonym test was reduced by hypoglycaemia. Fasting, which resulted in a body weight reduction of 2.6 +/- 0.3 kg and ketonuria prolonged the total reaction time (p less than 0.005) by increasing the moving time but did not affect the mental clearness test. When hypoglycaemia was preceded by 72 h fasting it did not increase the total reaction time, nor did it modify the mental clearness test. Moreover, the learning effect of the synonym test was less impaired. In conclusion, mental alertness was reduced by moderate hypoglycaemia after an overnight fast while similar hypoglycaemia did not reduce mental alertness after prolonged fasting. This may illustrate a decrease of the glucose dependency of the central nervous system during prolonged fasting.

Adult↗

PubMedDate not supplied

Branched-chain amino acid supplementation during 30-km competitive run: mood and cognitive performance.

It has been suggested that an elevated concentration of the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) in specific areas of the brain may contribute to the development of central/mental fatigue during and after sustained exercise. Supplementation with branched-chain amino acids (BCAAs) should prevent the exercise-induced increase in the plasma concentration ratio of free tryptophan to other large neutral amino acids (including BCAAs) and thereby prevent an elevation in the level of 5-HT in the brain. In this study, subjects were given either a mixture of BCAAs in a carbohydrate solution or a placebo drink that contained only carbohydrates during a 30-km cross-country race. Several tasks to measure cognitive performance were performed before and after the race. When subjects were supplied with BCAAs, their performance in the different parts of the color-word test (words, colors and color words) was improved by an average of 3-7% (p < 0.05) after exercise, whereas there was no difference in performance before and after exercise in the subjects who were given the placebo. Furthermore, the experimental group, supplied with BCAAs, maintained their performance in the shape-rotation and figure-identification tasks, whereas an impairment in performance in these tests by 25% (p < 0.05) and 15% (p < 0.05), respectively, was found in the subjects who received the placebo. Thus, BCAA supplementation seemed to have an effect on the more complex tasks, whereas no effect could be detected on the less demanding tasks. However, an intake of BCAAs during exercise modified only slightly the exercise-induced changes in mood.

Adult↗