* Performance boosting drugs have long Olympic history
* Popular choices were strychnine, alcohol, amphetamines
* Experts fear cheats will always be one step ahead
By Kate Kelland
LONDON, Aug 1 (Reuters) - Forget anabolic steroids in easy-to-swallow tablets, or EPO in clean syringes. Ancient Olympic dopers got their pre-Games hormone boost from chewing on raw animal testicles.
The problem of some Olympic competitors taking potions, medicines and supplements to boost performance is as old as the Games themselves.
Even athletes of the 19th century thought nothing of fortifying themselves with coca leaves, cocaine and alcohol. Thomas Hicks won the 1904 Olympic marathon with the help of raw egg, strychnine and shots of brandy given to him at regular intervals by his attentive coach.
"Doping has always been part of the Olympics, but drugs have not always been seen as a problem, they have become a problem," Martin Polley, an Olympic historian at Britain's Southampton University, told Reuters.
TONICS, TINCTURES AND TESTICLES
Experts say what drove people to extremes then is probably similar to what drives athletes to dope now.
After all, the desire to win by any means must have been strong to induce athletes to eat raw testicles - although as Polley points out it was "probably also seen as a sign of masculinity".
The difference now is that drugs are safer, subtler and more sophisticated. And perception of cheating has changed.
Athletes competing in the earliest days of the modern Olympics, which began in Athens 1896, felt perfectly free to take medicines, stimulants and "tonics," says Vanessa Heggie, a sports medicine historian at Cambridge University.
Injections of strychnine, tinctures of cocaine and sips of alcohol were all used in normal medical practice to treat aches, pains and fatigue, she explained in an interview. The idea was that athletes should be able to take medicines to relieve ailments, just like anyone else.
"Athletes were basically taking all the medications and substances that normal people were taking - including strychnine, amphetamines and cocaine," Heggie said. "That's because at that time athletes were seen by society very much as people who were basically normal, but a little bit better."
As the perception of athletes began to change, so did attitudes on what medicines, supplements and stimulants they should be allowed to consume.
"What we consider to be a drug changes over time," said Heggie. "Sometimes it's a medication, sometimes it's thought of as food, and then sometimes it's things that are thought of as more illicit, like recreational drugs.
"And some substances are in all of those categories," she added. "Alcohol, for example, was taken by the Victorians as a medication, it's also a type of food, it's clearly used by us as a recreational drug."
FROM DOPING TO ANTI-DOPING
Polley says the change in attitude to drugs in sport was initially prompted by concerns about what drugs were doing to athletes' health.
He points to the death of Danish cyclist Knud Enemark Jensen at the Rome Games in 1960 - thought to have been caused by amphetamines - as a turning point for the International Olympic Committee (IOC) on doping.
"That's often seen as the moment at which the IOC realised there was a problem," he said.
From then on, the fight against doping has been building - along with the science of testing - but is often seen as a race against cheats who are always one step ahead.
As soon as the fight against stimulants and steroids began to produce results, potential cheats rapidly shifted towards blood doping in the 1970s and 1980s.
The IOC banned blood doping as a method in 1986, but was not able to put in place a reliable test for the blood drug erythropoietin (EPO) until the Sydney Olympic Games in 2000.
Now the World Anti-Doping Agency's "prohibited" list runs to hundreds of substances. And the liquid chromatography and mass spectrometry testing equipment at the London 2012 anti-doping lab can screen up to 400 samples a day for more than 240 banned substances in less than 24 hours.
Yet Olympic historians are sure dopers will always be ahead.
As Heggie puts it: "It's a race I don't think we can ever really win." (Writing and reporting by Kate Kelland, editing by Paul Ingrassia and Ossian Shine)