There have been plenty of worried glances cast at tennis since the Lance Armstrong report went off like a grenade in the sporting consciousness. And it's not surprising that the sport, like all sports, faces new, jaded eyes.

The release of the U.S. Anti-Doping Agency (USADA) investigation into Armstrong surprised even hardened observers with its details about the scale of doping and the lengths to which the cyclists were prepared to go. It's logical to wonder that if this could go undetected for so many years -- under the most stringent testing program in sports, no less -- who knows what else there could be? But tennis is a different sport with different limitations as well as different opportunities, and it needs to be examined in its own context. In cycling, for example, the Armstrong findings hardly came out of nowhere; the sport had long been trailed by doping accusations and positive tests, and Armstrong had been implicated at times.

Lance Armstrong, riding Sunday in Ellicott City, Md., is banned from events that follow World Anti-Doping Agency rules after he chose not to fight USADA charges. AP Photo/Steve Ruark

Tennis hasn't exactly been immune to positive tests either, but at least for the moment, it still seems to lack that sense of pervasive suspicion. The overall pattern of testing results also looks different to expert eyes. "In cycling, just given the examples of the past years, several [samples] have been found positive in several cyclists for testosterone, for EPO, for many, many substances -- which is not at all what we see in tennis," said Christiane Ayotte, director of the World Anti-Doping Agency's accredited laboratory in Montreal, where the majority of samples from tennis have been tested for over a decade. "So there is no reason to suspect something organized and to the magnitude of what we saw in cycling."

Ayotte, one of the most respected figures in anti-doping, added that it's not because the system is lacking. "The current program in tennis, for me, is one of the best," she told ESPN.com. "The reason why I'm saying this is tennis is following the steroid profile of the 25 best athletes, which is something that is very rarely done in major sports programs. So for one, I do think that this follow-up prevents administration of testosterone-related [substances], which is a major, major problem."

Viewed as a whole, the program yields enough information for a broad range of conflicting interpretations, but renders any single one inconclusive.

The testing regime

Tennis is estimated to spend $1.3 million annually on its respectable, if not top-of-the-line, anti-doping program -- about one-third of what cycling spends. The ITF runs the operation, with substantial funding contributed by the ATP and WTA tours and the Grand Slams. About 2,000 tests are conducted every year, and top players can expect to be tested about 10 times a year.

The main criticism of the program relates to out-of-competition and blood testing, particularly the decline in the number of blood tests over the past few years. In 2011, there were 195 out-of-competition urine tests and 131 blood tests (including 21 out of competition). That was down from 195 blood tests in 2006 and 2007, though all were in competition; out-of-competition blood testing did not begin until 2010.

Another problem is predictability. Although specific data is not available, player reports of when they are tested suggest strongly that most in-competition tests are after matches, usually losses; that leaves significant windows for when testing is unlikely. And all the years for which data is available indicate that in-competition blood testing is conducted only at Grand Slams.

Blood tests are necessary to detect the use of human growth hormone (HGH) and certain types of blood doping. Out-of-competition testing guards against use during training, the benefits of which continue after the substances have cleared the body.

During the last two tournaments of the year, both Andy Murray and Roger Federer called for more such tests. "[W]e do a fair amount of drug testing," Murray said. "But a lot of it has been urine, not so many blood tests. I think it's important to make sure we have all of those bases covered.

"I think tennis is a clean sport. But the more we can do to improve that all the time is good.

"I think the out-of-competition stuff could probably get better."

Federer said: "I feel I'm being less tested this time now than six, seven, eight years ago. I don't know what the exact reasons why we are being tested less. At this moment I agree with Andy: We don't do a lot of blood testing during the year."

Ayotte agreed that "the amount maybe could be increased," but pointed out practical challenges. "Everyone in the world does only a little HGH [testing]," she said. "The collection is much [more] difficult to do, it costs more, we have to receive the samples in 24 hours."

Policing HGH remains a significant challenge. However, Ayotte says, despite all the focus on out-of-competition tests, in-competition testing has improved drastically and can detect substances like EPO, even if taken in micro-doses (involving small amounts that clear the body in hours). "Absolutely, we now can do this very well," she said. "Maybe 10 years ago we were not this good, but now we can."

Referring to the 2010 Olympics, she added: "In the Vancouver Games, we had only one positive test for EPO and it was in competition between two races, and it was a micro-dose and we were very much able to detect it.

"Most of the positive tests we have [for EPO], 90 to 92 percent are in-competition testing. So in-competition testing is not so inefficient. On the contrary, because the athletes who dope will try to use -- as we saw described by the cyclists also -- for recovery."

The timing of a test is far more important than whether the sample is taken in or out of competition, especially for the three products that pose the biggest anti-doping challenge.

"Testosterone, EPO, growth hormone -- these are natural substances," Ayotte said. "When testosterone is taken orally, it can be detected for only 15, 20 hours. Same thing for micro-doses of EPO, HGH. Such a short window of detection. This is the difficulty."

A sample thus yields only a snapshot of a particular moment in time. But players are a moving target, and an increasing number believe that getting a fuller image of doping activities requires taking an investigative approach, like the one used by USADA.

Beyond testing

Sara Errani battled in her first Grand Slam final, but with tired legs she couldn't overcome a determined Maria Sharapova. AP Photo/Michel Euler

This kind of approach involves tracking athletes, looking for suspicious signs and questioning those involved. "Testing alone will never pick up anything but a fraction of doping in a sport," said Richard Ings, who headed the ATP's anti-doping program from 2001 to 2005, then became the chief of the Australian Sports Anti-Doping Authority until 2010.

"What is required is other means to complement testing to deter and detect doping in sport."

In an email interview, Ings said he thinks only governments have these means. "The future of the fight against doping in sport is anti-doping being taken over by strong government agencies backed by laws and compulsive powers," he said. "Testing will be a part of that process, but not the focus of that process."

In running both sport and government programs, he experienced the sheer difference in resources and measures available to government. "This is not about will by sports," he said. "This is about powers, and government have much stringer powers than sports to fight doping.

"From Balco to Armstrong, major breakthroughs in anti-doping have come via investigations carried out by government bodies using government powers and laws."

Success in tennis depends on a balance of talent and technical skills as well as fitness and strength, so doping has been regarded as having a more limited potential impact than it would in some other sports. But even a small edge can go a long way in a game in which the margins between players -- and victory and defeat -- are slim.

Although Ings says "estimating how much doping takes place in any sport is a guess," he emphasized that "the ability to recover quickly from injury or long matches, the ability to have extra stamina for long matches, the ability to play more tournaments each year -- all will have a significant benefit to that player" and would provide a boost in "ranking, earning capacity and length of career."

Most tennis players do not have the kind of medical personnel on the road with them that cycling teams do, which would make it difficult to use sophisticated and extensive doping the way Armstrong reportedly did. Fellow competitors are also not in private areas before and after matches, but in close proximity in locker rooms, treatment areas and players areas. That makes it harder to conceal surreptitious activity during these times.

The other side, however, is that a player could set up a more independent operation overseen by someone based in another location.

"As an individual sport, if doping were to happen it would be taking place behind closed doors," said Ings, also a former umpire. "Other players don't need to know. Just a doctor, the player and perhaps an adviser would be the extent of the doping circle.

"Key to the major doping activities uncovered in recent years has been a rogue physician. Such a physician has access to banned substances, can administer them to their clients, is aware of how testing works and doesn't work [in order] to ensure that positive tests are unlikely."

That's where tennis' most significant connection to the Armstrong report comes in: the driving role attributed to Dr. Luis Garcia del Moral, a doctor in Valencia, Spain, who was the team physician for Armstrong's team. Del Moral also worked with Italian top-10 player Sara Errani as recently as last year and has links to a nearby tennis academy where several pros have trained. Ings believes there needs to be an investigation into the identity and intentions of del Moral's other clients, but that this can be carried out only by the Spanish government. "Dr. del Moral has no requirement to speak to any international federation, but he can be compelled to talk to Spanish government authorities," Ings said.

The ITF has recognized the lifetime ban of del Moral that USADA imposed in July, but currently has no provision that stops individual players from having contact with him. At the U.S. Open, Errani stated that she would not associate with him anymore.

Players are subject to their own national anti-doping associations and that of the country they are currently competing in, though strictness and funding varies widely. ITF anti-doping head Stuart Miller said in an email interview that "the ITF welcomes any additional testing that is conducted by national anti-doping agencies." USADA, for example, conducted 14 tests on American players during the first half of 2012, including two on Andy Roddick, John Isner and Ryan Harrison, and on Serena and Venus Williams once.

But apart from testing, the amount of investigation done either by these agencies or the sport is not clear. "The ITF has the power of investigation," said Miller, "and has exercised that power on occasions. The details of those investigations are subject to confidentiality requirements."

Mariano Puerta made headlines by reaching the 2005 French Open final, but his success was soon nullified by a positive drug test. AP Photo/Michel Euler

It was through government authorities that tennis made, arguably, its most revealing anti-doping catch to date: Australian customs officials found HGH in Wayne Odesnik's baggage when he arrived in the country at the beginning of 2010. Odesnik has never admitted taking the product, though he was convicted of possession by an Australian court. The ITF initially had problems figuring out how to proceed because Odesnik had not actually tested positive, and there was outrage as he continued to compete for several weeks after details became public. He was then suspended, only to have the suspension reduced to a year in return for providing information and assistance, provoking yet more outrage from other players. Details of what happened have not been released.

Even so, it remains the most incriminating indication of doping in tennis, even among the many dozens of positives tests to date.

Tennis and doping

In 1985, tennis was the first sport to institute regular drug testing, initially for recreational substances. Several top players from the 1970s to '90s have admitted to recreational drug use at one time or another, but not to deliberately using doping products. Most positive tests have involved low-ranked players, but there have been significant names like Petr Korda and Mariano Puerta. But Puerta's test was in 2005 (Korda's was in the late '90s), and the anti-doping program continues to be dogged by the observation that it hasn't hooked a big fish since then.

Instead, the most high-profile cases have involved the cocaine positives by Martina Hingis and Richard Gasquet. Gasquet grabbed headlines with his "kissing" defense, which was nevertheless solid enough for an independent tribunal to give him a minimal penalty. In many cases, players have attributed their positive tests to prescriptions, emergencies, contamination or accidental ingestion -- some credibly, others questionably.

Some less direct but troubling signs are also difficult to ignore. Over the past decade, a few players like Andrew Illie, Nicolas Escude and Christophe Rochus have spoken out about their belief in widespread doping in the sport. "I'm sure there are guys who are doing it, getting away with it and getting ahead of the testers," said James Blake at the U.S. Open. Connections to tennis players were also made in the BALCO and Operation Puerta investigations.

Ironically, the sport's two most controversial episodes -- Andre Agassi's undisclosed positive test for a recreational drug in 1998, and eight positive tests for nandrolone that went unpunished in 2002 and 2003 -- meant little. Agassi's case was heard by an independent tribunal and he was the beneficiary of older, more lenient rules. The eight nandrolone positives, meanwhile, were part of a sudden outbreak of nandrolone findings involving dozens of players. Lab research eventually linked these to a previously undiscovered phenomenon that results in natural occurrence in certain circumstances; WADA rules no longer consider such a result a positive test.

Wayne Odesnik could be facing a two-year ban from tennis. William West/Getty Images

The ATP never publicly announced this, and both these two situations continue to be cited with suspicion. That reflects another weakness in the tennis anti-doping program: poor communication.

The ATP and WTA tours and the ITF prefer not to comment on the topic, even when attacked. They rarely reply to questions with any clarity or detail. When asked whether maintaining public confidence was an important aspect of the program, for example, Miller supplied a boilerplate response. "Questions are answered and perceptions are addressed to the fullest extent possible within the constraints to which the [tennis anti-doping program] is subject," he said. "Nonetheless, those constraints provide opportunities for speculation, and there's only so far that the responses can go to respond to that speculation. In any case, decisions will be made in the interests of having the best possible anti-doping program within existing constraints."

The opaqueness means that it's usually left to outsiders to provide the best explanations of the system. Take the occasional speculation about players receiving "secret suspensions," or even worse, tests being covered up.

Ayotte said that when the ATP was running the program, she never saw a positive test that was not followed up. She said it is "still the same" with the ITF.

She also notes that all results are recorded directly by the lab in the centralized Anti-Doping Administration and Management System database. "So automatically, if there is an adverse finding, WADA could follow up," she said. "If ever tennis decided not to sanction an athlete, WADA could ask for the decision. They could even bring the case to arbitration."

Even if those in charge don't welcome it, bouts of public scrutiny do help increase transparency and spur change. The heat was increasing even before Armstrong, thanks to Yannick Noah's accusations of Spanish athletes, the striking physicality of some matches and the accumulating examples of doping in other sports. And coincidentally or not, after a period of appearing to be going backward, the anti-doping program now looks as though it may be taking some steps forward.

"We're working hard to try to increase the proportion of out-of-competition testing, and particularly blood testing, and we've been working on that for a while," Miller told the Associated Press at the end of last year. "I'm hopeful that by the end of the year, we'll have made some inroads into improving that."

He also added, "We are looking very, very carefully at an athlete biological passport program in tennis."

This would involve ongoing monitoring of various medical indicators, like hemoglobin levels, that could be a sign of doping. The system, already in place in cycling and track and field, also has the potential to pick up an increasing number of substances over time and develop detection of new doping techniques. These developments and others mean that there is at least some prospect that anti-doping authorities will be able to keep pace with those determined to evade them. However, concerns remain about testing alone being far from sufficient, and it is unclear how and by whom the gaps will be filled.

Tennis fans may not be sleeping soundly these days, but if it's any consolation, neither may the dopers.