Lance Armstong was stripped of his seven Tour de France titles and banned from professional cycling in October 2012 after being accused of using performance-enhancing drugs. Armstrong confessed in January 2013 to doping during his cycling career.
Barry Bonds is baseball's all-time home run leader, but some commentators say there should be an asterisk by his record. Though he's said he never knowingly used steroids, two San Francisco reporters wrote a book alleging he used performance-enhancing drugs. He was indicted on charges of perjury and obstructing justice for allegedly lying to a grand jury investigating steroids, and convicted of obstruction of justice.
Lyle Alzado was known as one of the most vicious lineman to ever play the game, and he chalked up more than 100 sacks and almost 1,000 tackles. Before his death from brain cancer at age 43, he told Sports Illustrated he began using steroids in 1969 and that, "On some teams between 75 and 90% of all athletes use steroids."
Known as "Rocket" for his aggressive pitching style, Roger Clemens played pro ball for more than two decades, racking up seven Cy Youngs. He left Major League Baseball under a cloud of steroid allegations, despite a court finding him not guilty of perjury when he told Congress he never used the drugs.
At 6-foot-5 and 260 pounds, Alistair Overeem is known for putting mixed martial arts star Brock Lesnar into early retirement. Ahead of a heavyweight title match against UFC champion Junior dos Santos in May, Overeem tested positive for elevated levels of testosterone and was yanked from the card.
An early and chief accuser of Armstrong, Floyd Landis was himself stripped of his 2006 Tour de France title after testing positive for performance-enhancing drugs. He admitted doping in 2010, the same year he accused many other riders of doping as well.
As the most decorated Olympian ever, with 22 medals, Michael Phelps is known as a fish in human's clothing, but for a brief period in 2009, after a photo of him smoking a bong was made public, he also was known as a pothead. Despite losing sponsors, he quickly became known for swimming again, securing six medals in the 2012 Games.
Marion Jones was a world champion track and field athlete who won several titles in the 1990s and five medals during the 2000 Olympic Games in Sydney, Australia. After admitting in 2007 that she had taken performance-enhancing drugs, she was stripped of the gold medals and other honors won after the 2000 Games.
Known as "Lights Out" after knocking out four players in a high school game, Shawne Merriman entered the NFL with fanfare, earning 2005 Rookie of the Year honors. His 2006 suspension for steroid use prompted the "Merriman Rule," prohibiting any player who tests positive for steroids from going to the Pro Bowl that year.
After his former Texas Rangers teammate Jose Canseco accused him of using steroids, Rafael Palmeiro appeared before Congress to deny the allegations. Later that year, he was suspended from baseball for testing positive for steroids. He maintains to this day he has never knowingly taken performance enhancers.
Few NBA players have tested positive for steroids, not only because the sport relies less on raw strength and speed than other sports but also because the league didn't begin testing until 1999. Miami Heat forward Don MacLean became the first to fail a test in 2000, and he was suspended for five games.
After racking up awards in college football, Ricky Williams was picked in the first round of the pro football draft in 1999. After testing positive for marijuana in 2004 as a Miami Dolphin, Williams retired and studied holistic medicine in California. He returned to the Dolphins the following year, only to have more run-ins with the NFL drug policy. He retired again in 2011.
Bill Romanowski was known for hard hits on the gridiron, but he also violently attacked teammate Marcus Williams during a scrimmage while playing for the Oakland Raiders. In a lawsuit, Williams blamed the attack on Romanowski's "roid rage." Romanowski settled the suit and in 2005 admitted to "60 Minutes" that he used steroids.
Sprinter Tim Montgomery set the world record in the 100-meter dash in 2002, but the time was scratched after he was found to have used performance-enhancing drugs. Since his retirement, he has had other legal troubles including arrests for money laundering and heroin offenses. He was sentenced to jail time for both.
An Olympian and renowned longball hitter, Mark McGwire spent his entire career with the Oakland A's and St. Louis Cardinals, breaking the single-season home run record in 1998. In 2010, he admitted using steroids over the course of a decade but told Bob Costas in an interview he took them only for health reasons.
Ross Rebagliati won a gold medal during the first year of snowboarding at the 1988 Olympics. He was stripped of the medal after testing positive for the active ingredient in marijuana. It became fodder for late-night talk show jokes, but Rebagliati eventually got his medal back after it was determined marijuana was not a banned substance.
A winner of eight Grand Slam events, Andre Agassi was considered one of the most dominant tennis players of the 1990s. In 2009, the tennis pro acknowledged in his autobiography that he had failed a drug test for methamphetamine in 1997 but skirted punishment by blaming an assistant.
Regarded as the best soccer player after Pele, Diego Maradona was known for his deft footwork and knack for finding the net. In 1991, he was suspended for 15 months after testing positive for cocaine. He would later admit he was addicted to the drug for about 20 years and began using when he was playing for Barcelona in the 1980s.
A prolific sprinter in the 1980s, Canadian Ben Johnson routinely bested American Carl Lewis in the 100-meter dash. After winning the gold at Seoul in 1988, Johnson tested positive for a steroid. His coach said Johnson took the drugs to keep up with other athletes and later wrote a book saying all top athletes were using in those days.
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
Drug scandals in sports
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Drug scandals in sports
STORY HIGHLIGHTS
- FIFA will introduce biological passports to combat doping in football
- Global sport has been rocked by several recent doping scandals
- World Anti-Doping Agency calls for team sports to introduce biological passports
- 456 samples taken from 114 of the 820 qualifying matches for Brazil 2014 World Cup
(CNN) -- Soccer stars will face a more systematic regime of drug testing following world governing body FIFA's decision to introduce biological profiles for players.
The move comes as global sport is trying to crack down on drug cheats in the wake of recent doping scandals.
Lance Armstrong's loss of his seven Tour de France titles, followed by his admission of using performance-enhancing substances in an interview with Oprah Winfrey, brought the problem of drug use by athletes to worldwide attention.
And last week Australia was stunned by a government report which alleged many professional athletes are using forbidden drugs often supplied by organized crime groups.
USADA official: Armstrong lied to Oprah
Journalist's crusade to expose Armstrong
Doping club was like a badge of honor
Sports doping scandal rocks Australia
In Spain, the Operacion Puerto trial is now underway following an investigation, which began in 2006, into the widespread doping network operated by Dr. Eufemiano Fuentes.
Now FIFA is taking steps to address any possible use of banned substances within football, announcing its plan to bring in biological profiles following discussions between president Sepp Blatter and his World Anti-Doping Agency (WADA) counterpart John Fahey on Thursday.
The profiles, similar to the biological passports used within cycling, will first be run at June's Confederations Cup -- a warmup tournament for the 2014 World Cup, also being held in Brazil.
Biological profiles are built up by collating an athlete's drug test results over time, therefore making it easier to detect differences which could indicate the use of a banned substance.
Read: What are banned substances?
"We are very interested in continuing the work on biological profiles," Fahey said in a FIFA statement released Friday.
"WADA is very satisfied with the commitment of FIFA on the biological profiles, which will be run not only at the FIFA World Cup in 2014 but already at the FIFA Confederations Cup in June this year."
In an interview with CNN, Fahey said he saw no reason why football and other major team sports couldn't introduce biological profiles.
"I would like to see, particularly team sports, take up the athlete's biological passport," said Fahey. "There is absolutely no reason why not in the major codes of football, and in the major sporting events right throughout the world.
"That will do a lot to stamp out doping in sport, and most of those major codes can easily afford the cost of running (a biological passport) program and doing it well."
FIFA said a total of 662 urine samples had been taken across different competitions last year, namely the FIFA U-20 women's World Cup, FIFA U-17 women's World Cup, FIFA Futsal World Cup, FIFA Club World Cup, Brazil 2014 qualifiers and men's and women's Olympic football tournaments.
"To date, there has been one adverse analytical finding at a FIFA World Cup qualifier in October 2012," read the FIFA statement.
"We have been testing this at the FIFA Club World Cup in 2011 and 2012, we will continue at the FIFA Confederations Cup 2013 with blood testing unannounced at training camps and games," said FIFA's Medical Committee chairman Dr. Michel D'Hooghe.
"And it's our commitment to have all players participating at the 2014 FIFA World Cup having biological profiles."
FIFA said doping controls will be in place at 114 of the 820 qualifying matches for Brazil 2014 played worldwide, with 456 samples being taken.
"At these selected matches, four players are to undergo a doping control and out of those selected, one is drawn for EPO," continued the statement.
EPO is a hormone which aids the production of red blood cells, helping athletes train harder for longer.
"There is always more which can be done in the fight against doping, but we know FIFA has always been serious in this domain," added Fahey in the statement.
"We think the leagues can complement what FIFA is already doing, but we came here to thank FIFA for its collaboration."