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  • 1
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Scandinavian journal of medicine & science in sports 10 (2000), S. 0 
    ISSN: 1600-0838
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Sports Science
    Notes: Hemoglobin data have been available from ski teams beginning from 1987, and from 1989 to 1999 we have followed hemoglobin values in elite cross-country skiers in international competitions. The mean values at the 1989 World Nordic Ski Championships were lower than population reference values, as would be expected from plasma volume expansion associated with endurance training. However, an increase, particularly in the maximal values, became obvious in 1994 and rose further in 1996. These extreme values provide both a health risk to the individual athlete and unfair competition. After a rule limiting hemoglobin values was introduced, the drop of the highest values was remarkable: among men 15 g/l (0.23 mmol/l) and among women 42 g/l (0.65 mmol/l). It would appear that the rule had achieved its goal of limiting extreme hemoglobin values. Yet the mean hemoglobin concentrations in men and women have continued to rise, suggesting the continued use of artificial methods to increase total hemoglobin mass.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of medicine & science in sports 3 (1993), S. 0 
    ISSN: 1600-0838
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Sports Science
    Notes: Capillary morphometries in human skeletal muscle has been limited by technical problems in visualization. The purpose of this study was to develop a method for identifying capillary endothelium at the light level of resolution and to reassess the skeletal muscle capillarity in trained and untrained subjects. A lectin system of biotinylated Ulex europaeus I (UEA-I), a vascular endothelial marker, provided a stain dense enough for direct computer-aided image analysis. A morphometric comparison was made between Andersen's periodic acid-Schiff and the UEA-I capillary stains on tissue sections of human skeletal muscle. When identical fibers from adjacent sections were compared, the capillary density was 6% and cap fiber was 9% greater using die lectin method. Biopsies from 17 cross-country skiers were compared with those of 8 age-matched sedentary controls. The capillary density in the triceps muscle for the skiers was 536.1 ± 33.1 compared with 296 ± 17.7 for the controls. Longitudinal profiles that appear in skeletal muscle cross-sections suggest a more isotropic (random orientation) configuration of the capillary bed than proposed by the Krogh model. There were 50.6% more longitudinal profiles in the trained samples. The UEA-I lectin appears to be a valid and potentially useful marker for computerized image analysis of non-pathological vascular endothelium, and tie differences in capillarity between trained and untrained individuals may be greater than previously reported.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of medicine & science in sports 3 (1993), S. 0 
    ISSN: 1600-0838
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Sports Science
    Notes: Capillary morphometrics in human skeletal muscle has been limited by technical problems in visualization. The purpose of this study was to develop a method for identifying capillary endothelium at the light level of resolution and to reassess the skeletal muscle capillarity in trained and untrained subjects. A lectin system of biotinylated Ulex europaeus I (UEA-I), a vascular endothelial marker, provided a stain dense enough for direct computer-aided image analysis. A morphometric comparison was made between Andersen's periodic acid-Schiff and the UEA-I capillary stains on tissue sections of human skeletal muscle. When identical fibers from adjacent sections were compared, the capillary density was 6% and cap fiber was 9% greater using the lectin method. Biopsies from 17 cross-country skiers were compared with those of 8 age-matched sedentary controls. The capillary density in the triceps muscle for the skiers was 536.1 ± 33.1 compared with 296 ± 17.7 for the controls. Longitudinal profiles that appear in skeletal muscle cross-sections suggest a more isotropic (random orientation) configuration of the capillary bed than proposed by the Krogh model. There were 50.6% more longitudinal profiles in the trained samples. The UEA-I lectin appears to be a valid and potentially useful marker for computerized image analysis of non-pathological vascular endothelium, and the differences in capillarity between trained and untrained individuals may be greater than previously reported.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Scandinavian journal of medicine & science in sports 12 (2002), S. 0 
    ISSN: 1600-0838
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Sports Science
    Notes: Acclimatization to moderate high altitude accompanied by training at low altitude (living high–training low) has been shown to improve sea level endurance performance in accomplished, but not élite, runners. Whether élite athletes, who may be closer to the maximal structural and functional adaptive capacity of the respiratory (i.e. oxygen transport from environment to mitochondria) system, may achieve similar performance gains is unclear. To answer this question, we studied 14 élite men and eight élite women before and after 27 days of living at 2500 m while performing high-intensity training at 1250 m. The altitude sojourn began 1 week after the USA Track and Field National Championships, when the athletes were close to their season's fitness peak. Sea level 3000-m time trial performance was significantly improved by 1.1% (95% confidence limits 0.3–1.9%). One-third of the athletes achieved personal best times for the distance after the altitude training camp. The improvement in running performance was accompanied by a 3% improvement in maximal oxygen uptake (72.1 ± 1.5–74.4 ± 1.5 ml kg− 1 min− 1). Circulating erythropoietin levels were near double initial sea level values 20 h after ascent (8.5 ± 0.5–16.2 ± 1.0 IU ml−1). Soluble transferrin receptor levels were significantly elevated on the 19th day at altitude, confirming a stimulation of erythropoiesis (2.1 ± 0.7–2.5 ± 0.6 μ g ml-1). Hb concentration measured at sea level increased 1 g dl−1 over the course of the camp (13.3 ± 0.2–14.3 ± 0.2 g dl−1). We conclude that 4 weeks of acclimatization to moderate altitude, accompanied by high-intensity training at low altitude, improves sea level endurance performance even in élite runners. Both the mechanism and magnitude of the effect appear similar to that observed in less accomplished runners, even for athletes who may have achieved near maximal oxygen transport capacity for humans.
    Type of Medium: Electronic Resource
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