Marathon runners

A lap in most tracks that use the English system is 0.25 mi (English lap). In countries that use the metric system, a metric lap is 0.50 km. A champion marathon runner covers a mile in about 5.0 min. How many minutes will the runner take to run an English lap at that speed A metric lap ... 

A Sprinter Uses Creatine Phosphate Anaerobic Glycolysis to Make ATP, Whereas a Marathon Runner Uses Oxidative Phosphorylation... 

Table 49-11. Types of muscle fibers and major fuel sources used by a sprinter and by a marathon runner.

This value of 20 kJ/L O2 can be very useful for example, it can be used to calculate that a top-class marathon runner requires oxidation of 5 g of carbohydrate every minute during the race, provided that no other fuel is used. The athlete takes up 4 litres of oxygen each minute, which is equivalent to 4 x 20, or 80 kJ each minute as 1 g of glucose releases 16 kJ of energy, the glucose or glycogen used is 80/16 or 5 g each minute. 

See also Table 2.2. The percentage of the body weight as fat is 2-7%, elite male marathon runners. The average in female marathon runners is 15% with the lowest at 6% (for reference, see Noakes 1986). 

Oxygen is probably seriously limiting in elite marathon runners but possibly not in non-elite runners. 

The same distinctions hold in humans. Sprinters and marathon runners have different proportions of muscle fibers, and therefore different metabolisms. Sprinters have relatively more fast white fibers, and can run very rapidly, but not for long distances. Marathon runners, on the other hand, have more slow red fibers and can carry out aerobic metabolism for very long periods of time, although they can t go as fast. Well-trained, world-class runners may have as much as 90 percent of their leg muscle of one type or the other, depending on their sport. Some sports, such as basketball and soccer, involve both aerobic endurance and anaerobic sprinting these athletes tend to have both types of muscle fiber. Untrained individuals have about 50 percent of each type. The relative contributions of training and heredity to each type of metabolism remain unknown, although both play some part. 

The RQ is 16/23 = 0.71, which is assumed to be the case for all fats. For proteins, which are the sums of their component amino acids, the RQ is generally taken as 0.8. Thus, if a person were metabolizing only fat, RQ would be 0.71. Normally the RQ is around 0.82, however, it is possible to observe more extreme values. In a marathon runner, for example, the initial RQ is indeed close to 1, indicating that carbohydrate is largely being metabolized. At the end of the run, blood sugar is down by some 40% and the RQ is 0.77, indicating that most of the calories toward the end derive from fat metabolism. 

Excess physical activity can lead to constant damage to the bones. There are numerous examples of marathon runners who develop severe osteoporosis later in hfe. In women, heavy exercise can lead to decreased oestrogen levels, which predisposes to osteoporosis. 

In a cross-sectional study involving marathon runners, Willett et al. (38) used multiple regression to determine the effects that age, weight, height, average number of miles run per week and best marathon time had on the relationship between alcohol consumption and HDL cholesterol. Alcohol consumption was associated with an Increase in HDL cholesterol beyond the increase related to physical activity. 

If you were a long-highly developed white muscle fibers or red muscle fibers Hint Consult 1-igure 4.31. (Also sfw Collnick and Hodgson, 19fWi.)... 

A marathon runner, who had taken naproxen until 36 hours before the race, developed acute oliguric renal insufficiency that required hemodialysis 2 days afterwards (SEDA-12, 87). 

Apple FS, Rogers MA, Casal DC, et al. Skeletal muscle creatine Idnase MB alterations in women marathon runners. Eur J Appl Physiol 1987 56 49-52. 

Kallmeyer JC, Miller NM. Urinary changes in ultra long-distance marathon runners. Nephron 1993 64 119-21. 

Prior to a race, many marathon runners will try to increase their glycogen concentrations by loading up with foods with a high starch content, such as pasta. a-Amylase secreted by the pancreas will digest the starch into which of the following major products ... 

Summary 29-year-old marathon runner with acute episode of generalized myalgias, weakness, fatigue, and dark-colored urine with urine myoglobin/hanoglobin, hyperkalemia, and significantly increased CPK isoenzyme. 

Why do marathon runners eat large amounts of pasta the day before a big race Foods such as pasta, bread, and fruit are rich in carbohydrates. A carbohydrate is an organic molecule that contains the elements carbon, hydrogen, and oxygen in a ratio of about two hydrogen atoms and one oxygen atom for every carbon atom. Early chemists thought that carbohydrates were chains of carbon with water attached—hydrated carbon— which is how carbohydrates were named. Chemists now know that carbohydrates are not hydrated carbon chains, but the name persists. 

Why do marathon runners prefer beverages with sugar instead of amino acids during a long run ... 

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