At the end, Wilson Kipsang had reason !
He was able to recover the same shape of London 2012 (Virgin, not Olympics…), and in that shape to better the WR was a concrete chance.  Also, I had infos about the today weather not very optimistic (the previews was wind of 4 m/s which could disturb the race slowing down the athletes), and that was the main reason because I supposed possible a low 2:04:00, not a WR.
Instead, the weather was perfect, such as two years ago, and Wilson could produce his effort without fighting against bad conditions.
Wilson had with him some pacemaker, who did a very good job for the first 25 km.  After that distance, two pacemakers dropped out, and only one remaining, slowing down a little compared with the previous pace.  At 30 km, Wilson decided to increase the pace, having the WR in his mind and feeling his body completely ok.  Geoffrey Kipsang reacted immediately, while Eliud Kipchoge preferred to close the gap progressively.  In any case, at 35 km the 3 leaders were together.
At that point, Wilson increased his speed again, and Geoffrey suddenly lost contact.  Eliud Kipchoge tried to resist, but, when understood the speed was too fast for him, decided to distribute the remaining energies using his brain, and at the end the final time rewarded his tactical choice.
Wilson was able to finish very much faster than Makau in 2011, showing to have still fuel in his tank, and that the current WR is not his hypothetical top.  The possibility to run under 2:03:00 is for him real, finding again the same conditions and having the same shape.
Here there is the distribution of the race for the first 3 athletes, for sections of 5 km :
Wilson Kipsang Eliud Kipchoge Geoffrey Kipsang
5 km : 14:33 14:33 14:33
10 km : 29:16 (14:43) 29:16 (14:43) 29:16 (14:43)
15 km : 43:45 (14:29) 43:45 (14:29) 43:45 (14:29)
20 km : 58:20 (14:35) 58:20 (14:35) 58:20 (14:35)
HM : 1:01:32 1:01:32 1:01:32
25 km : 1:13:13 (14:53) 1:13:13 (14:53) 1:13:13 (14:53)
30 km : 1:28:01 (14:48) 1:28:01 (14:48) 1:28:01 (14:48)
35 km : 1:42:36 (14:35) 1:42:37 (14:36) 1:42:37 (14:36)
40 km : 1:57:12 (14:36) 1:57:30 (14:53) 1:58:45 (16:08)
Final : 2:03:23 (6:11) 2:04:05 (6:35) 2:06:26 (7:41)
Apart the WR of Wilson, there was another great performance coming from Eliud Kipchoge, who was only at the second marathon of his new career.  Due to his lack of specific experience in preparing marathon (training and competition), Eliud can have good room of improvement, and next year can be a new pretender for bettering the WR.
Instead, Geoffrey Kipsang again finished the fuel after 35 km, showing that his transformation in marathon specialist “full time” is still far : Geoffrey needs time for setting his engine in different way, making it able to create and to use a fuel with less glycogen and more fatty acids at the speed of a WR.
The competition was of good level, but of course less interesting compared with the male race.
The two strongest in the field (Florence Kiplagat, winner in 2011, and Sharon Cherop, winner of Boston in 2012) ran practically together for 35 km, with their personal pacers.  Always Florence was in front, with Sharon 5 meters behind.  The break came after 37 km, and didn’t happen because some attack from Florence, but because Sharon was not able to maintain the same speed.
Here there is the distribution of the race for the first 2 athletes, for sections of 5 km :
Florence Kiplagat Sharon Cherop
5 km : 16:32 16:34
10 km : 32:46 (16:14) 32:51 (16:17)
15 km : 49:25 (16:39) 49:27 (16:36)
20 km : 1:06:09 (16:44) 1:06:10 (16:43)
HM : 1:09:48 1:09:49
25 km : 1:22:56 (16:47) 1:22:57 (16:47)
30 km : 1:39:38 (16:42) 1:39:40 (16:43)
35 km : 1:56:37 (16:59) 1:56:39 (16:59)
40 km : 2:13:47 (17:10) 2:14:28 (17:49)
Final : 2:21:13 (7:26) 2:22:28 (8:00)
Florence was not in the same shape of two years ago, but after several problems during the last year (she had a stress fracture in one knee) the victory can be a good new start for a career that has to look at Rio 2016.

After the today WR, Wilson can be considered the most consistant marathon runner all time.
Now, he is the only athlete who ran twice under 2:04:00, and 4 times under 2:05:00.
Here there are all his marathons :
11 Apr 2010 Paris (1) 2:07:13
30 Oct 2010 Frankfurt (1) 2:04:57
07 Mar 2011 Otsu (1) 2:06:13
30 Oct 2011 Frankfurt (1) 2:03:42
22 Apr 2012 London (1) 2:04:44
12 Aug 2012 London (OG) (3) 2:09:37
09 Dec 2012 Honolulu (1) 2:12:31
21 Apr 2013 London (5) 2:07:47
29 Sep 2013 Berlin (1) 2:03:23  WR
Wilson is one of the most professional runners in Kenya.  In my opinion, there is only another  runner having the same care of particulars, and is Eliud Kipchoge.
I don’t say Geoffrey Mutai, Moses Mosop, Abel Kirui and the other big marathon runners are not serious in their training : but training is not only what you do running, it’s also how you rest, how you eat, which focus you have in your normal life.  And, under this point of view, Wilson is an exception in the field of Kenyan runners.
After every marathon, Wilson spends about 2 months going in the gym of Lornah Kiplagat, for rebuilding the level of strength lost during the specific training for long distances, and maintaining high level of flexibility and reactivity.  This is something other athletes don’t do, preferring to rest waiting their body can again be able to work at its best.  Specifically, we can see the difference of mentality between Wilson and other top runners in the behavior after some injury : the most part await the time can solve the problem, totally resting and looking for some business, while Wilson has in his mind the priority to attack the injury, giving great importance
Wilson came years ago to Iten from his village, after working in Police before running.  His father was a runner in the late ’70, and Wilson discovered to have great talent only when was 26.  So, different from the most part of other Kenyan athletes recruited in Police or Prison or Army because, already runners of good level, still young, the Corps want to invest for the future of the Team taking the best juniors, Wilson went Police for working (such as Abel Kirui), and only after some year started his training, discovering his attitudes.
In Iten, he built his house, and with the first money won running built a Church for people of his village.
Last year, he developed a perfect period of training before London in April, when dominated the race showing to be, at the moment, the number one in the world.
But after London he didn’t have time enough for using the strategy normally used after a marathon, since there were only 3 and half months before Olympics.  For that reason, Wilson reduced the period of “rebuilding” in the gym, and couldn’t train with the right volume of intensity, and for the Games his shape was not better than 80%.
After the Games, he invested good money building an Hotel in Iten, and for some time this business reduced his focus in training, so his result in London was not a surprise, also for himself.
But, from the beginning of the year, Wilson had in his mind only the idea to better the WR.  And, for this, the only possibility was in Berlin.
It’s not a case that the last 5 WR were in Berlin.
The first belongs to Paul Tergat (2:04:55, first men under 2:05:00, on 28 Sep 2003).
After this, we had Haile Gebrselassie fot two times (2:04:26 on 30 Sep 2007, then 2:03:59 on 28 Sep 2008, first under 2:04:00), and Patrick Makau (2:03:38 in 2011).
Now, it’s clear we can have two opportunities only for bettering the WR : Berlin or Dubai.
Dubai has a course better than Berlin, but not always the weather is perfect.  This happened in the last two years (2012-2013), but in the past Gebrselassie, trying to beat his own WR, found a growing humidity and strong wind against during the last kms, for the two times he competed there.
Other problem, Dubai has the biggest prize, but doesn’t offer any appearance, and this means the best athletes, having already high economical evaluation, are not interested to go running in the Emirates starting without any guarantee money.
There are other marathons with a fast course : Rotterdam in Spring, Chicago, Eindhoven and Frankfurt in Autumn.  But, about Rotterdam and Chicago, there is the uncertainty of weather, rarely perfect, while Eindhoven and Frankfurt frequently have the best conditions, but not budget enough for attracting the few runners able to attack the WR.
So, now it’s clear the only attack can be organized in Berlin, and next year we can see, probably, a new attempt, also because there is no Championship during Summer, and who wants to prepare himself for the WR can do without any disturb.
The WR of Wilson is also a good answer to all the idiots thinking that the marathon results of the beginning of the season (not technically good like in 2011) depended on most hard rules of antidoping.
Since Wilson and Eliud Kipchoge are Kenyan, in the full whereabouts regime, are tested frequently, and for every WR in middle and long distances there is the most sophisticated kind of test (with blood, urine and biological passport), I hope that finally people looking at doping only for explaining every result can change their mind, or, second option, shut up, finishing to be the best “testimonial” for doping with the idea that only taking something illegal is possible to run fast.

From Letsrun.com forum

"I want to solve the mystery.

In Kenya, we have a place called Nangili, where all the marathon runners living near Eldoret go for their long run.
About one month before the race, we use to do, with the most part of athletes, 40 km (20 km going a little bit uphill, from 2020m till 2180m of altitude, then coming back, with the second 20 km favourable) very fast, as control of the shape, and this is the last workout of full distance at high intensity.
Before 2010, nobody there ran under 2:13:00.
At the beginning of 2011, we started running faster, and Moses Mosop ran 2:07:15.
After his result in Boston, the most part of top marathon runners started to run faster in that course.
Last year, before London, Abel Kirui ran in 2:04:57, and this became the parameter for the other best athletes.
Wilson, in the past, was used to run in about 2:10:00 (before OG 2:09:12 in muddy conditions).
Looking at an attempt of WR, I advised him to put two new things in his training :

1. Something longer than 40 km (and he ran 45 km at 90% of Marathon speed)

2. More intensity (and consequentely longer recovery in between) in some of his workouts of distance.
So, he went on the normal course in Nangili (I repeat, 40 km with 20 going up and 20 coming back) in 2:03:32, beating the "course record" of Abel Kirui.

You must think I consider about 1 minute of difference every 10 km between the same training at sea level (tarmac and racing shoes) and in Nangili (normally, heavy training shoes and road with less grip). The difference in running there or at sea level, instead, if the condition of the road is the same, in my opinion is about 3.0 per km (30.0 every 10 km). This means Wilson practically ran, 4 weeks before Berlin, 40 km in less than 2 hours, referred to the conditions of the race.

And this is the secret for running fast during the race : running fast in training, and of course to fully recover these hard sessions, otherwise you go to kill yourself."