Never in the history of the Olympic triathlon has any woman arrived at the big race with a more formidable record that Gwen Jorgensen. Two recent World titles. A 2-year win streak. A killer run. And yet, hope for an upset rises in some contenders with great swims and fearless bike skills that they can fashion a breakaway not even Jorgensen can catch.

Perhaps the moment of truth will come on one of Rio’s white knuckle downhills? Or will it be on the hot streets of Copacabana as rivals fight for the gold?

Gwen Jorgensen, 30, USA
3-1

Jorgensen created a sense of invincibility known as ‘Gwensanity’ with a record 13-race win streak over the 2014 and 2015 seasons. She won five World Triathlon Series (WTS) races in 2014 and 7 more WTS races in 2015, plus the August 2015 Olympic test event in Rio.

During that streak, Jorgensen’s 10k run times ranged from 32:35 to 34:14. Her run superiority over her closest rivals ranged from 31 seconds to 2 minutes. It was great to have a big weapon, but the streak lived so long because coach Jamie Turner helped transform Jorgensen into a first pack swimmer and cyclist as well.

Jorgensen remains an odds-on favorite for Rio gold, but she showed some vulnerability in 2016. At WTS Gold Coast she lost 1:33 to Helen Jenkins and Flora Duffy on a bike breakaway and made up only 51 seconds on the run, ending her win streak. At the WTS Hamburg sprint, Katie Zaferes and Rachel Klamer gained a minute lead on the swim and bike leg and Jorgensen made up only 33 seconds on the run.

With two big hills on Rio’s multi-lap bike course, strong cyclists and top bike handlers like Flora Duffy, Helen Jenkins and defending gold medalist Nicola Spirig might try to make a break. But at the 2015 Rio test event, no one made a break and the race came down to Jorgensen’s wheelhouse - the run.

Helen Jenkins, 32, Great Britain
8-1

At her best, Helen Jenkins won the 2008 ITU World Championship, dominated the 2011 World Championship Series, and was the favorite for the 2012 Olympics before injuring her knee in a pre-race slip on a pool deck. Lacking training, Jenkins managed to stay among the leading five until the final kilometer of the run before falling back to 5th place.

Still brilliant, but what might she have done without all those injuries? An Achilles took her out of most of 2007. After her 2012 knee injury, she missed much of 2013 with a foot injury and spinal problem. Just before the 2014 Commonwealth Games she tore a plantar fascia tendon. And in 2015, she withdrew from the European Games with ankle problems.

She rediscovered her form early this year when she ended Gwen Jorgensen’s win streak at WTS Gold Coast, Jenkins’ first big win since 2012. Since then, Jenkins cut down her WTS race schedule (except for a 3rd place at WTS Stockholm) and is careful in workouts leading to Rio.

Nicola Spirig, 34, Switzerland
10-1

In 2015 Spirig was on the conventional path to Rio with a 3rd at WTS Cape Town. After she broke three bones in her left hand in a bike crash at WTS Abu Dhabi this year, coach Brett Sutton steered the defending Olympic champion away from the WTS circuit. Instead, Spirig took on three Ironman 70.3 races, won two and took 2nd at the other, and did some remarkable run workouts that included a 9:07 for 3,000 meters on the track – the equivalent of a 32:40 10k. So why respect that mark if it was a standalone workout? It came one day after a 30k run, and the night after a 6k swim/40k bike brick at 5,000 feet altitude. In her first Olympic distance (non-drafting) outing at Zurich 5150, Spirig had the 5th fastest swim including the men and finished 2nd overall to Ruedi Wild.

Was Sutton protecting Spirig from discouraging outings against in-form WTS stars during her recovery? “No,” said Sutton. ”We just wanted to make sure she didn’t re-injure her hand.”

Andrea Hewitt, 34, New Zealand
15-1

Hewitt is a proven top contender as evidenced by her U23 World Championship in 2005, a bronze at the 2005 Commonwealth Games, 3rd at the 2009 World Championship Series, 8th at the 2009 Olympics, 2nd overall at the 2011 World Championship Series including a win at the Grand Final, 6th at the 2012 Olympics, and 3rd in the 2012 WTS Series.

So what is her 2015 form? Second at New Plymouth World Cup, 3rd at WTS Gold Coast, 4th at WTS Yokohama, 6th at Leeds, and 2nd at Stockholm.

Non Stanford, 27, Great Britain
18-1

Stanford arrived in the spotlight with a win at the 2012 Under 23 Worlds and secured her reputation with a WTS World Championship title in 2013, capped off with a win at the 2013 Grand Final in London where she finished with a 33:12 run.

An ankle injury ruled out most of her 2014 season. Stanford was back on form midway through 2015 and secured her Olympic slot with a 2nd at Rio and took 2nd at the WTS Grand Final in Chicago. In 2016, she started strong with a win at the WTS Cape Town sprint. Nearing Rio, things went backward with a 9th at Leeds and a DNF at Stockholm.

Flora Duffy, 28, Bermuda
20-1

This year, Flora Duffy became a serious contender for an Olympic medal. She started with a 4th at WTS Abu Dhabi, a 4th at WTS Gold Coast, and a 3rd at WTS Cape Town. After a solo bike breakaway at WTS Leeds, she was run down by Gwen Jorgensen but held on for 2nd. At Stockholm, she scored her first WTS win, topping heavy hitters Andrea Hewitt, Helen Jenkins and Vicky Holland.

Duffy will be dangerous in Rio: she has a front of the first pack swim and has proved she can ride to a minute or 90 seconds breakaway over WTS heavy hitters. To top it off, she ran a 2nd-best 34:28 10k at Stockholm.

Vicky Holland, 30, Great Britain
22-1

Holland crashed and took 26th at the 2012 Olympics in London and placed 3rd at the 2014 Commonwealth Games. In 2015 she came into her own, winning two WTS races, taking 3rd at the Rio Olympic test event and placing 3rd at the Chicago Grand Final. This year, Holland stayed on course with a 6th at Cape Town, 3rd at Leeds and 4th at WTS Stockholm.

Katie Zaferes, 27, United States
26-1

Zaferes zoomed to the spotlight in 2015 with five 2nd-places and one 3rd place on the WTS circuit. She cooled off a bit with a 6th place at the Rio test event and a 6th at WTS Hamburg. After her high-level 2015, Zaferes endured a bit of a sophomore slump in 2016 with 6th place finishes at WTS Abu Dhabi and WTS Yokohama and a 10th at WTS Stockholm. Zaferes shook that off with a breakthrough WTS win at the Hamburg sprint, including a bike breakaway with Rachel Klamer which held Gwen Jorgensen to 3rd place.

Sarah True, 34, United States
30-1

At London in 2012, Sarah finished a heartbreaking 4th at the Olympics, 10 seconds back of the bronze, and she has been consistently excellent since then. In 2014, she was 4th at WTS Cape Town, 2nd at WTS London, 4th at the WTS Grand Final, 1st at WTS Stockholm, and took second behind Gwen Jorgensen for the WTS points title. In 2015, True took 3rd in the WTS season points with a 2nd at Gold Coast, 3rd at London, 4th at Hamburg and the Rio test event, and earning her Olympic slot with a 7th at the Grand Final in Chicago. This year she DNF Abu Dhabi, took 9th at Cape Town, and 15th at Leeds, gradually working toward form with a 6th at Stockholm.

Ashleigh Gentle, 25, Australia
33-1

At 25, Gentle is one of the younger Olympic medal contenders after an up and down 2015 which included a discouraging 19th place at the Rio test event and an encouraging 2nd at WTS Yokohama where she ran a 2nd-fastest 33:55.

Gentle had a more consistent 2016 which included a 2nd at WTS Abu Dhabi, 2nd at WTS Yokohama and 2nd at the Montreal World Cup. A strong swim and strong bike make her eligible to join a potential Duffy-Spirig bike breakaway at Rio and her 33:34 run at Yokohama gives Gentle a chance to hang on for a medal.

Barbara Riveros, 29, Chile
36-1

This 5-foot 3-inch Chilean packs a punch. In 2015, she won the Toronto Pan Am Games and was 4th at WTS Abu Dhabi and 5th at the WTS Grand Final in Chicago. This year she is rounding into Olympic form with a 5th at WTS Leeds and 6th at WTS Hamburg.

Rachel Klamer, 25, Netherlands
38-1

On the rise at age 25, Klamer made a steady climb to contention. In 2015 she scored a 6th at Gold Coast, 9th at Rio and 5th at the WTS Grand Final in Chicago. This year, Klamer was 5th at Gold Coast, 7th at Leeds and 2nd at the Hamburg sprint behind Katie Zaferes and ahead of Gwen Jorgensen. Most impressive: Klamer and Zaferes combined on a bike breakaway that put a minute into Jorgensen and rewarded Klamer with a silver, her first WTS podium.

Emma Moffatt, 31, Australia
40-1

The 2008 Olympic bronze medalist and 2009 and 2010 ITU world champion would love to make up for a crash-marred DNF at the 2012 Olympics. In 2015, she had an off again- (DNF Rio, 23rd at Abu Dhabi, 12th at WTS Gold Coast and at the WTS Grand Final in Chicago) on again (3rd at WTS Yokohama) season. This year, Moffatt earned her Olympic slot with a 7th at WTS Gold Coast and scored 7th at WTS Yokohama.

Lisa Norden, 31, Sweden
45-1

No triathlon aficionado could forget her magnificent duel with Nicola Spirig at the 2012 Olympics which left Norden 2 inches from gold. Since then, Norden took some time off, took a crack at 70.3 racing, and came back to the WTS circuit in 2015 and 2016 with mixed results that included 10th at WTS Abu Dhabi, 11th at Mooloolaba World Cup, DNF at WTS Gold Coast, 22nd at WTS Yokohama, and 29th at WTS Hamburg – sadly moving in the wrong direction as Rio approaches. Why so far from her 2009 form that brought her two WTS wins and 2nd at the Grand Final? In the past year Norden has been fighting a slipped disc, inflamed lung, and multiple calf tears.

Erin Densham, 31, Australia
50-1

Densham took a close 3rd behind Spirig and Norden at the London Olympics. That was even more impressive because it came after her long recovery from ventricular tachycardia surgery in 2009. Densham reached form early in 2012 with wins at Sydney and Hamburg and 2nd at San Diego.

Since then, she was far back in 2014 and a bad bike crash in March 2015 left her well out of the top 10 in five WTS races and with a DNF at Rio. This year was even more discouraging with DNFs at WTS Abu Dhabi and the Montreal World Cup bookending mid-30s place finishes at three WTS events.

Anne Haug, 33, Germany
55-1

Haug was front pack in 2012 and 2013 with three WTS wins including a victory at the 2012 WCS Grand Final. Her 2nd place at 2014 Auckland, however, was her last podium before 6 races out of the top 10 and a 7th at the Rio test event in 2015. This year a 4th at WTS Cape Town was a flicker of hope.

The field: 40 fine triathletes in the rest of the field
60-1.