The look on Melissa Bishop's face said it all.
The Canadian 800-metre star had just run the race of her life, at the best possible moment, on the world's biggest stage.
"I have never run faster in my life. It's the smartest race I have ever put down on a track," Bishop said of her performance in the final at the Rio Olympics last summer.
But it still wasn't enough.
Despite setting a new Canadian record (which she has since broken by running a 1:57.01), Bishop finished fourth in the Rio final, missing a bronze medal by 13 hundredths of a second. Perhaps more distressingly, she crossed the line close to two seconds slower than gold medallist Caster Semenya.
"I remember seeing my agent and just falling into his arms, thinking, I can't believe this just happened. What just happened?" Bishop recalled.
"And then I saw my dad, and my dad is a very emotional man and he was livid. Not because of how I raced, but because of the scenario we were in.
And he just kept telling me, 'You have nothing to be ashamed of.'"
The "scenario" of finishing well behind Semenya is a familiar one for competitors since the South African burst onto the scene at the 2009 world track and field championships.
As an 18-year-old in Berlin, Semenya blasted away her competition, winning by almost two and a half seconds and clocking the fastest time of the year.
But an achievement that might have been celebrated was instead subjected to suffocating scrutiny, the result of Semenya's elevated levels of testosterone.
Semenya, now 26, is described as intersex, meaning her body does not conform to traditional male or female physiques. She has a condition known as hyperandrogenism, which causes some women to produce higher levels of male sex hormones such as testosterone. Since testosterone is one of the key ingredients contributing to an athlete's strength and speed, many felt Semenya had an unfair advantage.
"She is a woman, but maybe not 100 per cent," Pierre Weisse, the IAAF's general secretary, said at the time.
Following the world championships, the IAAF (track and field's world governing body) barred Semenya from competition and she was subjected to controversial gender and sex tests, the results of which have never formally been made public.
In 2010, Semenya was permitted to return to the track, but the story was far from over.
The following year, the IAAF introduced a new set of regulations that restricted the eligibility of females with elevated levels of natural testosterone.
The rule stated if a female athlete's testosterone exceeded 10 nanomoles per litre, which is at the lower end of the typical male range, it would have to be suppressed. It's unclear exactly what measures athletes with elevated testosterone may have resorted to in an effort to remain eligible, but it's believed Semenya may have taken invasive hormone suppressing drugs.
Though she hasn't commented publicly on the matter, Semenya faded in relation to her competition during this period. At the 2012 London Olympics, where she was chosen to carry the South African flag into the opening ceremony, she finished second by a wide margin to Russia's Mariya Savinova, who was later found to be doping at the time. (Semenya had also been the runner-up to Savinova at the 2011 worlds).
The idea of restricting female athletes' testosterone levels was controversial, to say the least.
"Many activists grew concerned because intersex women are declared female at birth and many feminist activists feel that anyone who is declared female at birth should enjoy all of the rights of being female," says Joanna Harper, a transgender athlete and a medical physicist at Providence Portland Medical Center in Oregon who is also a consultant on gender issues with the IAAF and the International Olympic Committee. "Including competing in women's sports regardless of how much testosterone they carry."
In 2015, the Court of Arbitration for Sport agreed that the IAAF's testosterone-suppression policy was discriminatory and suspended it, paving the way for Semenya to return to dominance.
It was 19-year-old Indian sprinter Dutee Chand who brought the legal challenge. Chand had been barred from competing in numerous events because of her elevated testosterone levels.
Toronto lawyer James Bunting represented Chand at the hearing.
"The regulation is clearly discriminatory. It discriminates against certain women in the female category," Bunting says. "It was also discriminatory between men and women, as men aren't subject to the same regulations. They can compete with testosterone levels as high as they wish.
"The panel then asked itself, can this discrimination be justified because it is reasonable, necessary and proportionate?"
Bunting said the panel decided the regulation wasn't necessary because "the alleged advantage from naturally high testosterone levels wasn't shown to be such a significant advantage that it required segregation or a specific rule to deal with athletes."
At the same time, there isn't a lot of data on the exact advantages for female athletes who have elevated levels of natural testosterone.
The panel heard that men historically run or jump 10-12 per cent faster or higher than their female counterparts. There was no evidence presented that showed female athletes with naturally elevated testosterone levels enjoyed a similar advantage.
"The panel concluded that they didn't have an unfair competitive advantage," Bunting says. "One of the points the panel accepted is, when you look at athletes, there are all sorts of differences between one athlete and the next. They may have longer legs, bigger arms, more muscle mass, have better vision. And depending on what sport you are competing in, those type of genetic differences that people are born with naturally can provide an advantage for one athlete over the other.
"So the question isn't about whether there is an advantage. The question is whether the advantage is unfair to a point where it becomes necessary to have a regulation to deal with it."
No longer subject to the IAAF's demands for testosterone suppression, Semenya regained her dominant form and breezed to her first Olympic gold in Rio.
But the story for her, and others like her, isn't over.
The IAAF was given until the end of July to come back to the CAS to try to reinstate the pre-2015 rules. The process is still playing out, and will likely take months to reach a conclusion.
"They need to show the court that the athletic advantage that women with naturally elevated testosterone have is of such a degree that it requires regulation," Bunting says. "That advantage would have to be in the 10 to 12 per cent range. So they need to show they have a substantial, male-like advantage."
There is every indication the IAAF plans to be back in court.
"We were surprised by the CAS decision, and I think the IOC was too," IAAF president Sebastian Coe said recently. "We are looking again at this issue and will be talking to CAS at some time over the next year.
"But we need to remember these are human beings. This is a sensitive subject, they are athletes, they are daughters, they are sisters and we need to be very clear about this. We will treat this sensitively. We need to go back to CAS and we have the right people looking at this."
Recently, the IAAF gave an indication of the evidence it would be presenting. A new study, commissioned by the governing body and published in the British Journal of Sports Medicine, found that elite female track and field athletes with higher levels of testosterone enjoy a 1.8 percent to 4.5 percent competitive advantage over women with conventional testosterone levels.
The study was based on blood samples taken from male and female athletes competing at the 2011 and 2013 world championships. The study did not include athletes who were found to have hyperandrogenism.
"If, as the study shows, in certain events female athletes with higher testosterone levels can have a competitive advantage of between 1.8-4.5 per cent over female athletes with lower testosterone levels, imagine the magnitude of the advantage for female athletes with testosterone levels in the normal male range," said Dr. Stéphane Bermon, one of the authors of the study.
Still, the advantage is not close to the 10-12 per cent threshold established by the CAS in its Chand decision.
Whether the study will be enough to sway the panel, most athletes who race against Semenya insist that regulations are needed.
And it's not just Semenya. Some runners in the 800 final in Rio had suspicions about the testosterone levels of all three runners who reached the podium, including silver medallist Francine Niyonsaba of Burundi and bronze medallist Margaret Wambui of Kenya.
Polish's Joanna Jozik, who finished fifth, was pointed in her remarks following the race.
"The three athletes who were on the podium raise a lot of controversy," she said then. "I must admit that, for me, it is a little strange that the authorities do nothing about this. These colleagues have a very high testosterone level, similar to a male's, which is why they look how they look and run like they run.
"It hurts a bit. I saw Melissa Bishop, who was very disappointed. She improved her personal best and was fourth. It's sad, and I think she should be the gold medalist."
Britain's Lindsay Sharp finished sixth in the 800 in Rio.
"The public can see how difficult it is with the change of rule but all we can do is give it our best," she said after the race. "If you take away the obvious ones it's actually really competitive," she added, referring to the medal winners.
It's not just athletes who competed in the race who didn't like what happened. Joanna Harper says the Olympic 800 final was "absolutely not equitable competition" and is hopeful the IAAF can present enough scientific evidence to bring back the testosterone rules.
"If we allow intersex women to compete with their natural testosterone levels, many of these women will have such a massive testosterone advantage that in terms of equitable competition they should not be competing in the women's division," she says.
University of Toronto professor Bruce Kidd, a long-time member of the Olympic movement who helped with Chand's CAS case, says the legal bar for the IAAF is high if it wants to re-establish testosterone restrictions. But he believes there are factors beyond the science surrounding testosterone levels that should shape what the CAS, IAAF and IOC do next.
"On the men's side we celebrate differences, we encourage nations to send athletes regardless of how they look, their size, shape, and we celebrate those athletes who are at the extreme, the outliers," Kidd says. "In women's sport, the dominant discourse is that women should look like the European, North American Caucasian expectation of femininity and that they should conform to a hormonal requirement that belies the science and is not expected of the men."
With the IAAF world track and field championships happening now in London, this won't be resolved in time for the start of the women's 800 event on Aug. 10. Any appeal and subsequent CAS decision could take months.
Whatever the scenario is, Bishop plans on being in the 800 final in London on Aug. 13 — whether a podium finish is possible or not.
"If I'm honest, it's not something that's in the conversations I have with my friends in the 800," she said. "It's something you can't control.
"We have to race no matter what."