 |
| |
|
| |
|
| |
|
|
Gangerolf
|
 |
huuhh
May 2001
time: 06:28
|
|
quote:
It's not genetic, it's not cultural. |
Well this is what science says. If you don't like it, well too bad for you
quote:
Geneticist and exercise physiologist Claude Bouchard at Laval University in Quebec City, has run numerous experiments comparing two populations, French-Canadian and West African students. Using long needles inserted into the thighs of test subjects, Bouchard's team extracted tiny sections of fibers, which look to the naked eye like pieces of raw meat. They were chemically treated to reveal metabolic differences, put on a glass slide, and slipped under a high-power microscope, where they appeared as a collage of tiny red and white crocodile scales. The West Africans, by a ratio of approximately two to one, had more of the larger fast-twitch fibers. The researchers concluded that the force generating capacity of type-II muscle fibers at high velocity, the speed and tempo of movements, and the capacity of an individual to adapt to exercise training are all genetically influenced. |
quote:
Timothy Noakes, long-time director of the Sport Science Center at the University of Cape Town Medical School, and author of many scholarly books, including Lore of Running, has observed that black South Africans, who share much of their genetic ancestry with East Africans, sweep more than 90 percent of the top places in endurance races held in his country, despite the fact that blacks represent no more than one-quarter of the active running population. Noakes has attempted to figure out why in his laboratory. In a treadmill study, black marathoners consistently bested whites. Although white runners matched or exceeded the black runners at distances up to 5,000 meters, blacks were "clearly superior at distances greater than 5km." The fine print in the data was particularly revealing. There was a dramatic difference in the ability of the blacks to run at a higher maximum oxygen capacity. In the case of the marathoners, blacks performed at 89 percent of the maximum oxygen capacity, while whites lagged by nearly 10 percent. The muscles of the black athletes also showed far fewer signs of fatigue as measured by lactic acid. |
quote:
Although there is no one genetically consistent African population, the environment appears to have resulted in some characteristics shared across populations. Bouchard is persuaded that a large fraction of both West and East African blacks enjoy biological advantages for power or sprint events and endurance activities, respectively. "West Africans have more of the key anaerobic enzymes in their skeletal muscle, those enzymes being responsible for regenerating the energy in the muscle cell through anaerobic pathways," wrote Bouchard. We are talking here about a two-fold difference between a significant fraction of blacks from West Africa and whites from North America. East Africans, on the other hand, seem to have more ability to mobilize the energy stored in adipose tissue in other body depots and to use that energy for prolonged periods of exercise. The key point is that these biological characteristics are not unique to either West or East African blacks. These characteristics are seen in all populations, including whites. However, based on the limited number of studies available, there seems to be more African Blacks with such characteristics than there are in other populations. |
http://run-down.com/guests/je_black_athletes_p2.php
|
|
| |
|
| |
|
| |
|
|
|
Tingkai
|
|
To find the Northwest Passage
Aug 2001
time: 13:28
|
|
quote:
Originally posted by GP
Pull your head out of your butt.
F = f(x,y). Showing a strong dependance of F on x does not mean that there is no effect of y on F. (Unless you vary y and do the statistical null proofs.)
|
GP: You need to take your own advice. 
If you are saying x=environment and y=diet then I never said that a strong dependence on y proves x is not a factor.
What I said was the Berzerker's hot cause tall/cold cause shortness hypothesis is incorrect in and of itself.
There is ample emphirical evidence showing the hypothesis is not valid. The average height of people in cold regions can be tall, and average height of people in hot regions can be short.
Berzerker argues that this is the result of migration and that "These changes (caused by environment) take a long time."
However, the Han Chinese of the colder northern China are taller than the Han Chinese of hot southern China. Both groups share the same genes so they should have equal heights according to Berzerker's theories, but they do not. Not only that, the height difference is opposite to what Berzerker's theory would predict.
As well, we have evidence that changes in average height can occur over relatively short periods of time.
quote:
Originally posted by GP
Do you really believe that Masai tribesmen raised on fish would be the same height as Japanese raised on fish? Or vise versa with respect to being raised on milk and cattle-blood.
|
Yes, a change of diet will affect height. We have evidence that suggests this is true.
During the previous century, the average height of 17-year-old Japanese males increased by six inches. Most of that increase occurred during the post-WWII period.
The most accepted reason for this rapid increase in average height is the change in Japanese eating habits. They began to eat more western foods, and I'm not talking about McDonalds. I'm taking about eating/drinking more milk, cheese and wheat-based foods all of which were not traditionally part of the Japanese diet.
So as Japanese people began eating more western-style food, they began to grow taller.
However, the increase in average height might be a result of increase quantity of food consumed rather than just type of food eaten.
Still, it is clear that diet has a significant impact on height and it can overshadow genetic influences. Just because a Japanese father is short doesn't mean his son will be of similar height. The statistics show that Japanese sons are taller on average than their fathers.
|
|
| |
|
|
|
Tingkai
|
|
To find the Northwest Passage
Aug 2001
time: 13:28
|
|
Interesting links.
I thought the following was significant:
quote:
One tiny district, the Nandi [in Kenya], with only 500,000 people, sweeps an unfathomable 20 percent of major international distance events.
The Kalenjins of the Great Rift Valley adjacent to Lake Victoria, a tribe of half a million people, win 40 percent of top international distance running honors - and three times as many distance medals [at the 88 Olympics] as athletes from any other nation in the world.
|
If this is true then we could hypothesise that:
1) It is not all blacks who are fast sprinters;
2) It is not all East Africans who are fast sprinters;
3) It is people from specific tribes/communities.
This would make sense genetically. For some reason, these two tribes have genes that make them great runners. Those genes are confined within a small geographical area among people who happen to have black skin.
Now probably those "runner" genes have dispersed throughout East Africa to a lesser extent but are concentrated in one community.
This indicates a potential problem with the studies being done. The scientist goes to Africa and does a study of Kalenjin people and then jumps to the conclusion that results are valid for all black people. That might be true, but it is also possible that the people tested are actually from a select group that the scientist doesn't recognise.
So the question we should be asking is not why are blacks so fast, but whay are Kalenjin people so fast.
|
|
| |
|
| |
All times are GMT. The time now is 05:28.
Apolyton Time is 00:28. |
top of page
|
| archivepost |
|
Forum Rules:
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
|
HTML code is ON
vB code is ON
Smilies are ON
[IMG] code is ON
|
|
|
|
|
|
16-05-2003 00:55
|