Californian Greg LeMond’s three wins sandwiching a horrible hunting accident should be the stuff of legend but was not, and his countrymen still thought the Tour de France a tourist package deal. Until, that is, Texan Lance Armstrong put this most grueling of all athletic competitions on America’s radar, becoming a global marketing phenomenon and Livestrong inspiration. Alex Gibney started out to document the icon’s (maybe triumphant) return at thirty-eight from a two-year hiatus, but events would alter the thrust of what went from working title The Road Back to released The Armstrong Lie.

Before the director/co-producer was in the picture, the project was for a Matt Damon biopic based on the cyclist’s memoir, It’s Not About the Bike: My Journey Back to Life, but that concept was shelved and then re-invented as a non-fiction when the seven-time Tour winner unretired with the goal of winning again in 2009 and ’10.

Rumors of performance-enhancing drugs had long dogged the champion but never been proved despite myriad blood and urine tests, which he pointed to in denying anything but hard work. The scenario is familiar to even non-fans in almost any moneymaking sport. Cycling is enormously popular in Europe in spite of its history of doping allegations and scandals, prompting an October 22 New York Times piece, “Armstrong May Be Gone, But Doping Culture Is Not.”

Gibney boned up and, granted unprecedented access, devised new equipment such as reduced-size digital cameras aimed front- and back-wards and affixed to racers’ bikes. His crew had amassed more than two hundred hours of original and historical material when everything hit the fan and gave the lie to the feel-good story of not only surviving the Big C but going on to a pinnacle of physical success, then employing that victory for immense financial rewards and to help others deal with the fearful disease.

Rather than sulking or yelling foul, Gibney reversed course and reasoned that he could use his footage as background to a re-imagined study of what had driven its subject, not only to athletic celebrity stardom but also to vicious attacks on those who defied omertà in denying or doubting his achievements. The film now would seek to address the why of the comeback, without which the legend would likely have remained intact.

Oprah Winfrey got there first, by hours, on January 14 of this year, before the documentarian and his camera confronted Armstrong, not precisely humble and repentant but noticeably less aggressive. There is none of the personal beyond a couple of childhood and cancer-patient stills, seconds of two young daughters (for sympathy) and less of Cheryl Crow.

With the director’s voice narrating or his visage filmed among the numerous heads, the earlier use of alcohol and caffeine concentrate crushed with rat poison strychnine comes out, updated to various chemical PEDs and transfusions back of one’s own oxygenated blood. Doctors, technicians, trainers, athletes and management are implicated, one step ahead of federations who devise tests for banned substances but not infrequently have financial and jingoistic interests in hiding in plain sight the open secret of universal doping (such as, unmentioned, Spain’s allowing suspended teammate-enemy Alberto Contador to represent that nation during his unsuccessful appeal).

Just over two hours, The Armstrong Lie gives a good enough summary of the sport and its shenanigans (and by implication those of others) for Americans to get some understanding and appreciation. As is invariably the case, the interviewees are too many to keep straight, and most have their axes to grind, anyway. Overriding them, however, are Lance Armstrong and the reiterated Big Lie that illustrates how desperately the global public wants to have its heroes, believe, and be entertained, or hoodwinked, by the zillion-dollar spectacle that sport has degenerated into. With Armstrong and his attacker Floyd Landis stripped of their titles, first non-European-ever LeMond is again the only American to don the Tour winner’s yellow jersey, and he is now being called into question.

(Released by Sony Pictures Classics and rated “R” for strong language.)