* Judo player expelled after eating marijuana brownie
* Scientists question reasons for banning cannabis in sport
* Little evidence to suggest it could enhance performance
(Adds more detail on cannabis and sports, no comment from WADA)
By Kate Kelland
LONDON, Aug 6 The expulsion of an American judo
player from the London 2012 Olympic Games on Monday after he
tested positive for marijuana prompted scientists to question
the sense behind the drug's inclusion on the World Anti Doping
Agency's (WADA) banned list.
Few experts think marijuana, or cannabis - whether it's
eaten or smoked - can do much to enhance the kind of speed,
strength, power or precision that Olympic athletes strive for.
And many wonder whether the expensive time and effort of
sporting drug testers might be better spent catching serious
cheats who top up their blood with EPO or pop anabolic steroids
to boost testosterone levels and muscle growth.
"There's no evidence cannabis is ever performance enhancing
in sport, and since its use is legal in a number of countries,
there's no reason for it to be banned by WADA," said David Nutt,
a professor of neuropsychopharmacology at Imperial College
"I can't think of any sport in which it would be an
advantage. And it seems ludicrous that someone could quite
legally smoke cannabis in Amsterdam in the morning and then come
over to London in the afternoon and be banned from competing."
The heart of the problem is where to draw the line between
performance enhancing drugs - which many experts agree should be
prohibited in sport because they make the contest unfair - and
recreational drugs like marijuana, which is unlikely to boost
performance but could give sport a bad image.
SCIENTIFIC OR POLITICAL?
While it is generally accepted that cannabis is unlikely to
give athletes any advantage in fast-paced sports, some experts
say it could prove helpful in sports like shooting or golf where
a steady hand is needed.
Under WADA's rules, athletes face a two-year ban if cannabis
is found in their system while they are in competition.
But the anti-doping body does not sanction those who test
positive for marijuana outside of competition times, while they
are in training camps or during rest periods.
Scientists say this smacks of double standards and suggests
WADA bans cannabis for political rather than scientific reasons.
"The problem is the elite athletes should be seen as role
models for young kids, and so they ban cannabis because they
don't want to have the image of gold medallists smoking joints,"
said one British-based sports scientist who asked not to be
identified because of the sensitivity of the issue.
A photo of the American swimming champion Michael Phelps
inhaling from a glass pipe used for smoking marijuana in 2009
sparked criticism from the U.S. Olympic Committee.
In a statement released shortly after the picture was
published by a British tabloid newspaper, Phelps admitted to
smoking pot and apologised for what he described as "bad
judgment". He did not receive a doping ban because it was not
Experts say that row, as well as Monday's ruling on American
judoka Nick Delpopolo - who said he inadvertently ate the drug
in a marijuana brownie - is far more to do with the image of
sport than any form of cheating.
"It's hard to imagine how smoking a joint or eating
marijuana brownies is going to help somebody in judo," said
Michael Joyner, a member of the Physiological Society and a
researcher at the Mayo Clinic in Minnesota in the United States.
"My advice to WADA is that they should focus on drugs that
are clearly performance enhancing in the sports where they are
clearly performance enhancing."
Some national sporting bodies are also kicking back against
Australia's Coalition of Major Professional and
Participation Sports called in May for marijuana to be removed
from the list saying it was wrong to group it with performance
enhancing drugs like human growth hormone and steroids.
Substances on WADA's banned list should meet two of the
following criteria: they are proven to be performance enhancing,
they are dangerous to the health of athletes, or they are
contrary to the spirit of sport.
While there are few signs that marijuana can enhance
sporting performance, there is evidence to suggest it could have
a negative impact.
Studies have shown that THC - the ingredient in cannabis
that induces the "high" - increases blood pressure and heart
rate while also decreasing cardiac stroke volume, leading to
diminished peak performance.
It can also slow reaction times, cause problems with
coordination, reduce hand-eye coordination, and interfere with
Anti-doping authorities were not keen to discuss the issue
Officials at UK Anti-Doping declined to comment, and when
Reuters sent emails to WADA's media relations office asking for
a statement on why cannabis is banned, WADA responded by saying
it was too busy to provide a comment on Monday.
WADA president John Fahey indicated in May the agency may
look at changing the criteria for cannabis as a banned substance
for athletes, but no decision is expected this year.
(Editing by Ossian Shine/Greg Stutchbury)