If there was a lighter side to a week in which doping dominated the sports headlines, it came in the discovery of O-desmethyltramadol in a sample taken from a horse called Wotadoll. Sitting in judgment, the British Horseracing Authority’s disciplinary committee accepted the explanation that the metabolite of the opioid tramadol – detected after the three-year-old bay filly finished unplaced at Wolverhampton – could be sourced to the urine of a groom who peed in the horse’s box after taking the medication for pain relief.

The Racing Post called it “an embarrassing leak” but peeing in a horse’s straw is apparently a common practice among Britain’s incontinent stable lads when they are supposed to be mucking out. The horse’s trainer, Dean Ivory, was fined £750. Later he announced his staff will be reminded of the proximity of the toilet block and, just to be on the safe side, encouraged to wear gloves.

There was also a four-legged animal involved in the announcement of Alberto Contador’s retirement: the creature from which, according to the multiple winner of cycling’s grand tours, a piece of meat had been taken and carried from Spain by a friend to provide him with a nourishing steak dinner during the 2010 Tour de France. Contador’s explanation of the clenbuterol found by drug testers failed to avert a two-year suspension and an expunged third victory in the world’s biggest bike race. Some admirers of his attacking style wanted to give the Spaniard the benefit of the doubt but his departure will sever another link with the era of Operación Puerto.

We ought to be beyond the stage of giggling at claims of cocaine traces picked up by a tennis player through kissing a girl in a Miami nightclub (Richard Gasquet in 2009, who was cleared of all charges by the court of arbitration for sport) or too much sex on his wife’s birthday producing an unnaturally elevated level of testosterone in a sprinter (Dennis Mitchell in 1998). It was certainly easier to keep a straight face while reading about the two-month suspension handed this week to Sara Errani, formerly the world’s No5 female tennis player. A test had revealed traces of letrozole, a drug used to treat her mother’s breast cancer and apparently picked up from a kitchen work surface.

But neither laughter nor compassion seemed an appropriate response to the soap opera of the men’s 100m final in the world championships last weekend, when the “two-time drugs cheat” Justin Gatlin helped deprive Usain Bolt of a golden farewell to the event in which the Jamaican is a triple Olympic champion. That is because there is no appropriate single response. Gatlin’s case is an awkward one, exposing the layers of moral complexity that can defeat the human urge to make a clean separation between right and wrong.

Gatlin’s first offence, at the age of 19, was for traces of amphetamine, said to have been given to him since childhood as part of a treatment for attention deficit hyperactivity disorder. Non-medical people might be surprised to find amphetamine used as a remedy for ADHD but that is apparently the reality of it and the authorities reinstated him halfway through a two-year suspension, while warning that any further offence would trigger a life ban. But by the time he was pinged for testosterone in 2006, while being coached by the notorious Trevor Graham, the rules had changed and he was given an eight-year ban which his lawyers succeeded in getting halved on appeal. So now we have Bolt retiring when clearly past his best at 30 and Gatlin – who is currently coached by none other than Mitchell – running faster than anyone at 35.

An hour or so before Gatlin celebrated his victory by raising an admonitory finger to his lips in response to the London crowd’s boos, Almaz Ayana had surged away from her rivals with a solo attack a mere 4km into the women’s 10,000m final. The Ethiopian ran the next 3km at a speed that would have won all but one of the women’s 3,000m races run throughout the world this year. The last 3km were barely any slower. To anyone not taking that into consideration it was a beautiful sight – like watching Michael Johnson in Atlanta in 1996, for instance. Such unanswerable dominance always takes the breath away until, as with Ayana, one is reminded of what it may mean.

Those who had read Martha Kelner’s investigation into drug testing in Ethiopian athletics – or rather the inefficiency of it – in these pages that very morning may have been rather less starry-eyed. They may even have wondered if this was a clear demonstration of the old maxim that, if something looks too good to be true, it almost certainly is. Ayana, of course, has previously declared herself “crystal clear” when answering inevitable questions in post-race press conferences. Only Jesus and training, she said, were responsible for her success.

And then there is Icarus, the documentary about the Russian government’s involvement in doping made available on Netflix and given a limited cinema release in this of all weeks. Bryan Fogel’s two-hour film starts small, with an experiment to see if he can improve his own performance as a competitive amateur cyclist through following the full Lance Armstrong menu of performance-enhancing drugs. But his encounter with Grigory Rodchenkov, who ran Russia’s anti-doping lab while simultaneously helping the country’s athletes to give it the swerve, leads him down another path, one that exposes the biggest state-run PED programme since the Berlin Wall came down.

The film traces a line from Rodchenkov and his colleagues through Vitaly Mutko, then the country’s sports minister and now its deputy prime minister, all the way to Vladimir Putin, who has used sport to help build his image as the embodiment of a newly virile Russia. The all-shootin’, all-fishin’, all-ridin’ Putin flashes his pecs at the world to emphasise that dominance – whether of an Olympic podium or in the annexation of neighbouring territory – is his nation’s natural and rightful characteristic.

The fact that Rodchenkov and his fellow whistle-blowers Yuliya and Vitaly Stepanov are in a US witness-protection programme illustrates the scale and gravity of the problem for sport. We are not in Iffley Road now, watching a medical student and his chums achieve immortality. We are in the world of strong-arm geopolitics, where people can be made to fear for their lives.

As it turned out, all the EPO and testosterone in the world could not make Fogel into a great bike racer. In fact they made him worse. In any other film that might have raised a laugh – but not in this film, not in this week, not in this world.