Olympic champion and world record holder Eliud Kipchoge will take a second crack at trying to break the two-hour barrier for the marathon when he participates in the Ineos 1:59 Challenge in the fall. The attempt was announced on the 65th anniversary of Sir Roger Bannister's first sub-four-minute mile and is backed by a British chemicals firm and billionaire Jimmy Ratcliffe.

In May 2017, Kipchoge participated in Nike's Breaking2 attempt on a Formula1 course in Monza, Italy. He covered the 26.2-mile distance in 2:00:25, but the time was not eligible for a world record by the International Association of Athletics Federation due to the time trial's use of an alternating cast of pacers. During Breaking2, a rotating crew of runners would hop in and out of the race in a predetermined formation to hold sub-two hour pace ahead of Kipchoge. A pace car also helped block the wind from the runners. Assistants biked alongside Kipchoge and the runners to hand over fluids and drinks when needed so that he would not have to slow down for a table at a water station. Much like Breaking2, it is expected that the 1:59 Challenge will also optimize conditions and pacing strategy and not comply by IAAF rules. 

Last fall, Kipchoge clocked a 2:01:39 to win the 2018 Berlin Marathon and officially broke the world record by 78 seconds. Most recently, Kipchoge won his fourth London Marathon title and set a course record in 2:02:28, which ranks as the second-fastest time in history. After running in Monza in 2017, Kipchoge told Sports Illustrated that Breaking2 was the best race of his career.

“I learned a lot from my previous attempt and I truly believe that I can go 26 seconds faster than I did in Monza two years ago," Kipchoge said in a release. "It gives me great pride to accept the challenge presented by Ineos. I am very excited about the months of good preparation to come and to show the world that when you focus on your goal, when you work hard and when you believe in yourself, anything is possible”.

The location and date for the Ineos 1:59 Challenge are yet to be announced. Sean Ingle of The Guardianreported that some early ideas feature plans to host it in London's Battersea Park in front of 250,000 spectators on Oct. 13. The IAAF world championships will be held from Sept. 27 to Oct. 6 in Doha. A marathon on Oct. 13 would overlap with the Chicago Marathon.

“The course also has to be flat, a good surface, and it can’t have corners which are too sharp,” Ratcliffe, who also took over the Team Sky cycling team, toldThe Guardian. “Secondly, we have to find pacers to keep up. Then, it is about having the right environment and a crowd to lift Eliud’s spirits, as in Monza it got a bit lonely. A lot of this is about pain tolerance. What level of pain are you prepared to tolerate?”

In a 1991 paper, Dr. Michael Joyner, a physiologist at the Mayo Clinic, argued that a 1:57:58 marathon was theoretically possible for an ideal runner—for instance, someone with a high level of maximum oxygen consumption. In Oct. 2018, Sports Illustrated caught up with Joyner, who predicted "the over/under at 2028 or 2029" for the first possible sub-two.

By participating in the Ineos 1:59 Challenge, it appears that Kipchoge will bypass on the fall world marathon major season. When his year isn't interrupted by the Olympics or Breaking2, Kipchoge has typically run London in the spring and Berlin in the fall. Last month, he told reporters that he's interested in running all six world marathon majors before he retires. He has won London four times, Berlin three times and the Chicago Marathon once; he has yet to race Boston, New York or Tokyo. He also plans on defending his Olympic gold medal at the 2020 Summer Games in Tokyo.

Kipchoge will turn 35 in November and has already proven himself as the greatest marathoner in history. He dismantled a strong field in London and would probably do the same if he went back to Berlin in the fall. Could he win Boston, Tokyo or New York while being a little past his prime? Possibly. There's still time for him to race those and potentially become the first person in history to win all six major marathons. However, the Ineos 1:59 Challenge is intriguing and served as at least one more test for the world to witness one of the best athletes in the world pushing his limits in a race against the clock.