SINGAPORE - Keen observers of long-distance running all over the world, including those from Singapore, will cast their eyes this weekend on a race track whose asphalt loop is known more for motor racing than marathon running.
Many will hope for the romantic notion of another breakthrough achieved exactly 63 years after Roger Bannister's sub-four minute mile. But as far as local experts are concerned, it is unlikely to happen - at least not yet.
For a start, they feel breaking the two-hour barrier in the marathon demands an improvement too big - in too short a span of time - even for the world's best runners.
Kenya's Eliud Kipchoge, Eritrea's Zersenay Tadese and Ethiopia's Lelisa Desisa would have to muster a lifetime best effort - and more - in order to go faster than any man ever has over 42.195km (or 26.2 miles).
Compared to the pace at which Kenya's Dennis Kimetto ran when he set the world record of 2hr 2min 57sec at the 2014 Berlin Marathon, it means speeding up by about seven seconds per mile (1.6km).
Said Ivan Low, a research fellow and exercise physiologist at the National University of Singapore: "This requires an improvement of about 2.5 per cent from Kipchoge's previous best (2:03.05 at the 2016 London Marathon). From a physiological perspective, that is a very, very huge improvement.
"It's not impossible, but given that the world record has improved by about 2 per cent over the past 15 years, to go that much faster in a year or half a year, is very tough."
Nike, the American athletic apparel giant behind this endeavour, unveiled its bid to go under two hours in December last year.
Low explained that an elite runner typically has reached, or is close to, their maximum potential. Any improvement over a personal best thus comes marginally.
"It is more realistic for a less trained individual who has not realised his or her full potential to improve by 2.5 per cent, but these elite runners have probably hit the plateau phase of improvement. To go faster by two to three minutes is very significant."
To aid the three runners as much as possible, many variables that can disrupt or impede a good marathon effort will be controlled.
They will be guided by a group of pacers who are themselves champions; the Monza Formula One track in Italy was carefully chosen for its average temperature, air pressure, wind levels and even surface; while drinks will be served on the move to eliminate slowing down.
The runners will also be decked out in Nike gear, including shoes whose curved carbon-fibre plate inserts have raised eyebrows.
Said veteran long-distance running coach Steven Quek: "These guys, first of all, have to be able to perform around 2:03 on that day. And that doesn't happen that often to begin with."
Kimetto's world record is the only sub-2:03 time in history. There are 14 other sub-2:04 marks set from 2008 onwards, all but one of them posted by Kenyans.
Added Quek, who coached marathoner Neo Jie Shi at last year's Olympic Games: "The time will improve, runners will continue to improve, but to jump so much in a short span of time is unlikely. Three minutes is quite a lot to make up."
But the trio attempting to make history this weekend may have a psychological advantage, said national marathoner and 2013 SEA Games champion Mok Ying Ren.
He said: "It's challenging to sustain going faster over a marathon, but I've not had the experience of running in a controlled environment. When you know you're going to be paced, there's no wind, the route is flat, psychologically you will feel this is the day. It may be possible."
Sports physician Dr Ben Tan, a marathon enthusiast himself and a former national sailor, said at least one thing can be counted upon: That the current world record of 2:02:57 can be improved on.
He said: "(That record) was not achieved under optimal circumstances - whether we're talking about training, race conditions, or the genetic make-up of the runner.
"We're still fine-tuning and... we haven't seen the fastest time yet."