As the Vancouver 2010 Winter Olympics come to a close tomorrow, I find myself reflecting over the past couple of weeks in amazement at what the human body can accomplish. Feats of strength, agility, concentration, precision - why is it that some of us are better than others??
The science of the olympics is complex - involving physics, chemistry, exercise physiology, biology and many other disciplines. Here is a brief summary of just some of these topics in the news this Olympic season:
Doping and Performance Enhancement - chemistry, biology, and sports physiology:
Whether athletes can continue to break world records in various events without the aide of drugs, or whether competition without restrictions on performance enhancers shoud be allowed are continuous topics of discussion during the olympics. Are these drugs really enhancing human ability, or just restoring some athletes to a normal state? Should performance enhancers be strictly outlawed in sports and other aspects of life (ie: study aides like rittalin)? Where can the line be drawn to include performance enhancers - what about things like altitude training and genetics? Below are some excerpts from experts on these issues:
The excerpts below are by Timothy D. Noakes (New Engl. J. Med. 2004 351:847) http://scienceweek.com/2004/sc041001-5.htm:
2) Drugs have been in sports for a long time. In the earliest modern Olympic Games, the drugs of choice included strychnine, heroin, cocaine, and morphine,(4) which were probably more harmful than helpful. The first "effective" performance-enhancing drugs, the amphetamines, which were used widely by soldiers in the Second World War, crossed over into sports in the early 1950s.(4) These drugs -- nicknamed "la bomba" by Italian cyclists and "atoom" by Dutch cyclists -- minimize the uncomfortable sensations of fatigue during exercise. By setting a safe upper limit to the body's performance at peak exertion, these unpleasant sensations prevent bodily harm. The artificial manipulation of this limit by drugs places athletes at risk for uncontrolled overexertion.
3) The first cases of fatal heatstroke in athletes using atoom were reported in the 1960s. In the 1967 Tour de France, elite British cyclist Tom Simpson died on the steep ascent of Mont Ventoux, allegedly because of amphetamine abuse. The precise extent to which amphetamines enhance athletic performance is unknown, since, as with all performance-enhancing drugs, there are few modern studies quantifying their effects. The convenient absence of such information represents further evidence of a hidden problem. A popular opinion is that la bomba can turn the usual Tour de France domestique, or support rider, into a stage winner.
4) Since amphetamines must be present in the body to be effective, the sole method of avoiding the detection of their use during competition is to substitute a clean urine sample for the doped specimen. A multitude of innovative techniques have been developed to accomplish this swap.(2) Cortisone, a potent but legal performance-enhancing drug used to dampen inflammation, also reduces the discomfort of heavy daily training and competition and lifts the mood. It is also widely abused by professional cyclists.(2)
5) Testosterone propionate (Testoviron), the prototype of the anabolic steroids, the second major group of potent performance-enhancing drugs, was synthesized in 1936 and appeared in sport sometime after the 1948 Olympic Games. The subsequent synthesis of methandrostenolone (Dianabol) in the USin 1958 and oral chlordehydromethyltestosterone (Turinabol) in East Germany after 1966 marked the beginning of the "virilization" of modern sport.(4) By increasing muscle size, these drugs increase strength, power, and sprinting speed; they also alter mood and speed the rate of recovery, permitting more intensive training and hence superior training adaptation. For maximal effect, anabolic steroids are used in combination with other hormones that have similar activity, including insulin, growth hormone, and insulin-like growth factor. They have multiple side effects, some of which are serious, including premature death.
The following comments are from the British Journal of Sports Medicine in2004 (http://bjsm.bmj.com/content/38/6/666.extract):
The use of performance enhancing
drugs in the modern Olympics is on
record as early as the games of the third
Olympiad, when Thomas Hicks won the
marathon after receiving an injection of
strychnine in the middle of the race.1
The first official ban on ‘‘stimulating
substances’’ by a sporting organisation
was introduced by the International
Amateur Athletic Federation in 1928.2
In 1992, Vicky Rabinowicz interviewed
small groups of athletes. She
found that Olympic athletes, in general,
believed that most successful athletes
were using banned substances.4
Drugs are much more effective today
than they were in the days of strychnine
and sheep’s testicles. Studies involving
the anabolic steroid androgen showed
that, even in doses much lower than
those used by athletes, muscular
strength could be improved by 5–20%.5
Most athletes are also relatively unlikely
to ever undergo testing. The International
Amateur Athletic Federation
estimates that only 10–15% of participating
athletes are tested in each major
competition.6
The World Anti-Doping Agency code
declares a drug illegal if it is performance
enhancing, if it is a health risk,
or if it violates the ‘‘spirit of sport’’.10
They define this spirit as follows.11 The
spirit of sport is the celebration of the
human spirit, body, and mind, and is
characterised by the following values:
- ethics, fair play and honesty
- health
- excellence in performance
- character and education
- fun and joy
- teamwork
- dedication and commitment
- respect for rules and laws
- respect for self and other participants
- courage
- community and solidarity
People do well at sport as a result of the
genetic lottery that happened to deal
them a winning hand. Genetic tests are
available to identify those with the
greatest potential. If you have one
version of the ACE gene, you will be
better at long distance events. If you
have another, you will be better at short
distance events.
There is no difference between elevating
your blood count by altitude training,
by using a hypoxic air machine, or
by taking EPO. But the last is illegal.
Some competitors have high PCVs and
an advantage by luck. Some can afford
hypoxic air machines. Is this fair?
Nature is not fair. Ian Thorpe has
enormous feet which give him an
advantage that no other swimmer can
get, no matter how much they exercise.
Some gymnasts are more flexible, and
some basketball players are seven feet
tall. By allowing everyone to take
performance enhancing drugs, we level
the playing field. We remove the effects
of genetic inequality. Far from being
unfair, allowing performance enhancement
promotes equality.
Phenomenal Physics:
Scientists in various fields study the physics of sport and motion. Understanding of the physics of a hockey slapshot or aerial skiing, the mathematics of motion, and the science behind safety equipment are just a few of the topics. Check out these great NBC Learn pages, in association with the National Science Foundation, for video clips explaining these aspects of Olympics Science (and more!):
http://www.nsf.gov/news/special_reports/olympics/
http://www.nbclearn.com/olympics
Curling, one of the oddest sports at the Winter olympics, is a great example of applied physics. Here is an explanation by curler and physicist Dr. Mark Shegelski (from http://www.icing.org/game/science/shegelsk.ht):
Any curler knows that a curling rock, rotating counter-clockwise (when viewed from aboveand behind) curls to the left. But to a scientist new to the game, it is surprising. Why so?
Consider an overturned drinking glass sliding over a smooth surface and rotating
counter-clockwise: the glass will curl to the left? No, it curls to the right! This may be
surprising to the curler (ed. note: an empty overturned glass may be even more surprising)
but it is fairly easy for the scientist to explain.
As the overturned glass slides over the smooth surface, it tends to tip forward.
Consequently the front of the glass pushes harder on the surface than the back does. Thus,
the friction on the front of the glass is greater than the friction on the back. For a
counter-clockwise rotation, the "sideways" motion of the front of the glass is to the left,
so the sideways component of the friction on the front of the glass is to the right, and
the glass curls to the right. You can easily check this out, and when you do, you will see
that the glass does indeed curl opposite to a curling stone.
Why then is the curl of the curling stone opposite to that of the drinking glass? The
reason is that the friction on the front of the rock is less than the friction on the back.
How can that be? Part of the explanation is the following. Like the overturned drinking
glass, the curling stone tends to tip forward as it slides down the ice, and so the front
exerts a greater pressure on the ice than the back. More pressure on the front means that
the front of the stone causes more melting (momentarily) than the back. Consequently, the
front of the stone will have less friction than the back. For a counter-clockwise rotating
rock, the sideways motion at the back will be to the right, and the friction at the back
(which is greater than on the front) will be to the left, and bingo, there it is. The rock
curls to the left. (See diagram below.)
Simple, eh? Well, not quite! If that was the whole story, curling rocks would not curl
nearly as much as they do. The friction on the front is not only less than on the back: it
is much less, especially when the rock is slowing down, coming over the hog line and into
the Free Guard Zone or the house. This explains why curling stones curl most at the end of
their motion.
Due to the motion of the rock over the ice, there will be a momentary melting of the ice
and the formation of a thin film of liquid just beneath the running surface (contact ring)
of the rock. As the rock slides and rotates, the thin contact ring will tend to drag some
of the thin liquid film around it as it rotates. There is a force of attraction between
granite and water: water tends to cling to granite. Thus, the thin liquid film under the
rock tends to get dragged along with the rock.
As the rock slows down, this thin liquid film is dragged around the rock, from the back
along the side and eventually to the front. Consequently, the front of the rock will have
even less friction on it than the back (as the rock slows down) and that is why we see most
of the curl happen near the end of the rock's travel.
These main ideas were the key ingredients in a scientific model I developed, along with
my co-investigators at UNBC. All of the details are given in four papers we published
(three in the Canadian Journal of Physics; the other in the Australian Journal of Physics).
It is important to note that our work was carefully evaluated by other scientists before
publication. We didn't just come up with an idea. Our ideas and calculations were carefully
tested and have passed those tests. That is why we can say, quite confidently, that our
explanation is correct.
In science, a good model is one where predictions can be tested: our model makes two
significant predictions that have been tested and have passed with flying colours.
Our model concerns the motion of a rapidly rotating, slowly sliding curling rock (in
curling parlance, a "spinner"). The other concerns the shape of the pattern of contact
between the rock and ice.
Suppose you took a curling rock and spun it as fast as you could manage, and pushed it
only slightly, so that the rock was rotating very rapidly and sliding over the ice so
slowly that it would only move from one side of the house to the other? What would you see?
Our model predicted that because the rock was sliding so slowly, the contact ring would
have ample time to drag some of the liquid film around it. In fact, the liquid would be
circling around the rock at an appreciable fraction of its rotational speed. The result
would be that the frictional forces would change so that friction would stop the rock
sliding long before it stopped rotating!
In conclusion, we tested our ideas by predicting specific results, and these were then
confirmed by experiments that supported our ideas. Why does a curling stone curl the way it
does? Because (1) melting occurs as the rock slides over the ice, and (2) the rock drags
some of the thin liquid film around it as it rotates, making the friction much less at the
front than at the back of the stone, especially when it is in its final feet of travel.
In a counter-clockwise rotating rock, the "sideways" motion at the
the front is to the right (solid arrow). The sideways motion at the
back is to the right, and the friction is to the left. Because the
friction at the back is greater than at the front, the rock curls
to the left.
Websites worth exploring, related to this topic:
http://btc.montana.edu/Olympics/
http://www.scientificamerican.com/report.cfm?id=2010-winter-olympics
http://www.popularmechanics.com/outdoors/sports/2285836.html
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Michael Steinberg
doctorwascher
Paul Hinrichs
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Salon.com
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