DOHA, Qatar -- When the 2019 IAAF World Athletics Championships begin Friday in Doha, Caster Semenya will be marooned elsewhere, kicking a soccer ball as a therapeutic outlet for her frustrations.
The conversation around South Africa's omnipotent 800-meters runner has drowned out much else in track and field for most of this year. Controversial regulations have effectively barred Semenya from defending her title unless she agrees to take medication to lower her testosterone levels -- a policy, concocted by the sport's guardians, that they insist is necessary to negate the genetic advantage of so-called athletes with "differences of sexual development."
Staying away, she insisted last week, "doesn't mean I'm no longer a track and field athlete." Yet in recent months, as legal appeal and counter-appeal have brought at least a short-term certainty to her exclusion, the chatter has drifted to those able to score big when athletics' global showpiece lands in the Middle East for the first time.
One year out from the Tokyo 2020 Olympics, the rest of the best of the best will gather and attempt to seize the golden opportunities to lay down a mark.
Five storylines to watch
The heat is on
The air-conditioning, organizers have promised, will be turned up to the max inside Doha's Khalifa International Stadium come Friday night.
It will be hot and humid outside and 14 degrees Celsius (57 degrees Fahrenheit) within -- all so that the leading track and field stars can keep their cool at the championships and preserve their energy for burning off rivals.
Mainly due to the heat, and in part to cultivate new audiences, the Doha schedule has been condensed into the evenings alone, making it ideal for television audiences in the heartland of Europe while still facilitating the Americas.
The controversy watch
Allegations of conspiracy and corruption linger from the decision, made five years ago, to take one of the biggest sporting spectacles to Qatar, a peninsula of 2.6 million people, which will use the nine days of competition as a small dress rehearsal for the FIFA World Cup in 2022.
The buildup has not been free of off-track distraction. American sprinter Christian Coleman -- whose time of 9.81 seconds tops the 100m rankings -- was set to miss the event because of a series of missed anti-doping tests before a loophole freed him to take part.
South Africa's Carina Horn was suspended last week for a positive test. The regulations corralling Semenya have also excluded others. While Russia is still barred as a nation for its unresolved transgressions, some of its nationals have been individually cleared to compete.
IAAF president Sebastian Coe will hope that his prime-time showcase passes without further miscues and that the hubris created by drama and dynamism can complement efforts to reimagine the sport and address its decline in popularity.
The next Bolt
What Coe covets is the arrival of a transcendent totem to fill the void that still exists following Usain Bolt's retirement after the 2017 worlds in London.
Track in the U.S. has long been confined to the shadows, only to emerge into the limelight once every four years.
Likewise within Europe, the sport's finest exponents are not the celebrated names they once were. Heroes help. A combination of charisma, charm and magnetic attraction to championship triumph is a rare gem to find.
In the search for a successor of sorts to Bolt, the U.S. has arguably track's leading light in Noah Lyles, the 22-year-old from Florida who claimed both the 100- and 200-meter titles in this summer's Diamond League series.
He is openly targeting the Jamaican's world record of 19.19 seconds in focusing solely on the longer event. "I will only run the 200 meters," he said. "Because I want that gold so much."
It is a shame, in truth, that he will not double in the 100, still the blue riband of the sport. Instead, returning champion Justin Gatlin, now 37, will be Coleman's chief rival, with Nigeria's Divine Oduduru, winner of the NCAA title this year as a junior at Texas Tech, holding the potential to thwart plans for American dominance.
The leading women
Can British hope Dina Asher-Smith raise herself to gold amid a deep and quick pack? Seasoned Jamaicans Elaine Thompson and Shelly-Ann Fraser-Pryce remain a tough one-two punch, especially with the brilliant Bahaman Shaunae Miller-Uibo funneled exclusively into the 400 meters because of an unwillingness to bend the schedule to accommodate her full range of gifts.
Minus Semenya and others, an American 1-2-3 is achievable in the women's 800 meters, with Ajee Wilson aligned to Raevyn Rogers and Hannah Green. While Scottish terrier Laura Muir will be favored for the 1500m, the Netherlands' Sifan Hassan has swept aside all others in the 5000m and 10000m.
In the field, the USA's Christian Taylor is primed to maintain his dominance, and Cuban prospect Juan Miguel Echevarria now has the consistency to leap beyond reach.
As ever, predictability and surprises will align, side by side. The Qataris, given a platform to tout their country to a global audience, intend to put on a show. Their reigning high jump world champion, Mutaz Essa Barshim, has not recovered his best form following injury. Local celebration might be in short supply. Selling an abundance of tickets at a time, when the host nation is off-limits to many of its neighbors, has proven to be an awkward challenge.
Yet track and field's appeal has always been its simplicity: run more quickly, throw farther, leap higher and longer.
For nine days in Doha, the sport will hope that the chatter is similarly uncomplicated, that it surrounds human boundaries pushed and outstanding efforts applauded, and that somehow, the younger fans the sport craves can be duly enthused.
And as the world watches, the sport hopes to see legalities and politics and assorted other concerns kicked firmly into touch.
Five athletes to watch
Noah Lyles (USA, 200m, 4x100m relay)
The title of the undisputed Fastest Man in the World remains vacant. Is Lyles ready to inherit Usain Bolt's belt? The American will make some noise, whatever occurs, with his own hip-hop album already in circulation and a sideline in clothes design ensuring that he looks as sharp as he runs.
He has pledged to add the splash of color to the sport that Bolt once brought. "I was interested in what was his way of making people want to watch the sport," he recently told reporters. "And that's what I believe I took the most from." First things first: emulating the Jamaican's magnetic pull toward gold.
Dina Asher-Smith (Great Britain and Northern Ireland, 100m, 200m, 4x100m relay)
The quickest woman in Europe now wants to conquer the world. The U.K.'s leading light, now 23, underlined her ascent by picking up this year's Diamond League title over 100m. Expectations and pressure will not bother her. She has ducked under 11 seconds in that event in all but one appearance this summer. But the 200m might be her strongest distance -- with her peak potentially still ahead. Amid a crowded field of rivals, nothing is certain, she admits.
"The World Championships is going to be the first time where we see everybody with nowhere to hide," she said. "Because if you are not ready for the World Championships, when are you ready?"
Allyson Felix (USA, 4x400m relay)
Having run only a small clutch of races since returning from pregnancy in July, the six-time Olympic champion will be confined to the relay as she hunts a 12th world championship gold. Much attention has been centered on Felix's row with Nike over contractual clauses surrounding maternity leave that opened a very public debate. But 11 months after the arrival of her daughter, the 33-year-old will not settle for secondary status, despite funneling her attention toward the Tokyo Olympics.
"Things change a little bit, just with what you want to accomplish, where I'm at in life," she told ESPN.com. "What is most important for me right now, as far as on the track, is definitely Tokyo and preparing for that. And so, every decision is with that in mind: making sure that I'm at my best to try to make that team."
Juan Miguel Echevarria (Cuba, long jump)
At the 2017 worlds in London, Echevarria exited quietly in qualifying. It was the latest in a string of poor showings under pressure. Since then, the 21-year-old has captured the World Indoor and Pan American Games titles while producing a wind-assisted jump of 8.92 meters in March, the longest in the sport in more than 23 years.
After falling just 3 centimeters short of Mike Powell's 1991 benchmark, Echevarria told the IAAF website that a new best is within his range. "The world record is a very difficult mark to break," he said. "But it's not impossible."
Sifan Hassan (Netherlands, 1500m, 5000m, 10,000m)
Ethiopian-born, Dutch-raised and based out of the Nike Oregon Project, the 26-year-old has collected two world bronzes and has moved up a gear in 2019, setting a world record of 4:12:33 in the mile in July in Monaco and adding a European 3000m best at June's Pre Classic in San Francisco.
So versatile has Hassan become that she has entered three events in Doha. She would be the favorite in each, but the 1500m or 5000m will be dropped from her schedule. Regardless, two golds seem realistic for her to cap a season in which she has surprised herself. "At the start of my training for this year was not good," she said last month. "And now it just turned out to be an amazing year for me."