61'45 is NOT a suicidal split !

I agree, not to mention they are all slightly better than they were las year. I doubt we will see a repeat of last year.

There is a big drop in the first five kms. The big drop from Ha Ha Road to Woolwich Road is at the end of the first 5k. John Wilson Road drops about 40m and overall elevation drop on the course is around 35m. That crazy opening split has a lot to do with that early down hill and isn't a necessarily suicidal early effort for an athlete attempting 2:03:xx.

There is a big drop in the first five kms. The big drop from Ha Ha Road to Woolwich Road is at the end of the first 5k. John Wilson Road drops about 40m and overall elevation drop on the course is around 35m. That crazy opening split has a lot to do with that early down hill and isn't a necessarily suicidal early effort for an athlete attempting 2:03:xx.

that drop is more like 30m & maybe worth 5+ sec quicker than flat road, but they still went 3rd mile in 4'28 which is still too fast compared to a 4'43 on flat road

30m downhill sounds a lot, but it probably isn't worth more than 5s+

here is boit's downhill mile wr report

near 200m drop in a mile cost something like 20 - 25s ( scott ran 3'47.69 year before & looked in perhaps even better shape in '83 - see oslo mile of '83 ), so 30m drop is going to be ~ 5s level

the subsequent 14'33 last year was on a flat part

I guess we will find out tomorrow

Last year, there was a big surge right before the HM. 20-25 km ended up being 14:30 with a fast first half of it. That one hurt a little too. 20k to half-marathon was 3:06 which is a 2:49 1k.

not part of original discussion but surprisingly good prelim results from downhill races from just taking tan of downhill angle

208y downhill of 1760y hypotenuse is angle of 6.78 degrees

tan of this is 0.119

add 1 -> 1.119

3'28.36 * 1.119 = 3'53.16

needs lot more research but surprisingly good results ?!

also tallies well with my long held gut feeling that a 1m smooth drop in a 100m race in 10.00 costs about 0.1s

here, angle is arcsin ( 1/100 ) = 0.5729 degrees

tan this = 0.0100, then add 1

10.00 * 1.01 = 10.10

for the ~ 30m drop in 3rd mile of 4'28

arcsin (30/1609.344) = 1.068 degrees

tan it = 0.0186

add 1,

4'28 * 1.0186 ->4'33

probably good starting method for general working purposes...

I agree it is fast. But this is a longer drop. It drops from about 50m when the race leaves Shooters Hill at 1.5 miles to about 5m at 5 miles by Woolwich ferry at the foot of the hill. So by Boit's calculations isn't that more like 17 seconds? Granted there is a 10m climb in the first 1.5 miles.

Not trying to be difficult. I just live somewhere near the top of the hill and so run a similar route to and from work and I know how much slower I am coming back. It is not insignificant. In the race, everybody seems to get to the bottom at 5 miles, looks says 'oh crap, I have to slow down'. Then it settles down.

*Correction

5 miles = Charlton

5k = Woolwich ferry.

lives near the hill wrote wrote:I agree it is fast. But this is a longer drop. It drops from about 50m when the race leaves Shooters Hill at 1.5 miles to about 5m at 5 miles by Woolwich ferry at the foot of the hill. So by Boit's calculations isn't that more like 17 seconds? Granted there is a 10m climb in the first 1.5 miles

the course map shows all the significant drop is within just over 1 mile, from 2 miles to say 3.2 miles, call it 1.2 miles

that's a drop of 40m

40m over 1.2 miles = 33.3m over 1 mile

boit's mile was 208y drop = 190m, a drop more by ratio of 190/33.3 = 5.7

divide 5.7 into 20 - 25s boit got advantaged ->

3.5 - 4.4s

it's still not much of an advantage

doing it "formally" by tan method

arcsin 40m/1.2 miles = 1.18 degrees

tan it = 0.021

advantage was 0.021 for that 1.2 miles

1.2 miles on flat course at even pace is 4'42/mile = 5'38.4

5'38.4 * 0.021 = 7s

the more accurate method is indicating 7s gain

still not much

Roughly according to this

http://www.freemaptools.com/elevation-finder.htm

Elevation at start = 40.0m

Elevation at 1.3 miles (highest point) = 49.3m

Elevation at 5.3 miles (lowest point) = 4.2m

Elevation at 5k = 28.5m

Elevation at 10k = 6.8m

Elevation at half way = 15.3m

Elevation at finish = 13.5m

1.3 miles to 5.3 miles is where some of the crazy pace comes from. You'll have to do the maths, but what should gain be between 49.3m and 4.2m be?

that's 4 miles gap which at 4'42wr pace on flat is 18'48

the drop is 49.3 - 4.2 = 45.1m over 4 miles or 6437m = angle 0.401 degrees which gives tan of 0.007

multiply this by 18'48 =

7.9s

call it 8s advantage at start, but they give some of it back after 5.3 miles

Yes, the course takes back between 17 and 19 miles with a slow climb and then the weaving around Canary Wharf. What wind there is will be going in going against the general direction of the race.

By those calculations I have always gone way to quick over that stretch. Probably explains some of the second halves I've had in London.

It is going to be an exciting race whatever happens. Do we know the six in the 61:45 group?

Oh

Paula's splits from 2003

London 2003

1m - 5:10

2m - 10:18 (5:08)

3m - 15:15 (4:57)

4m - 20:22 (5:07)

5m - 25:32 (5:10)

6m - 30:54 (5:22)

10km - 32:01

7m - 36:06 (5:12)

8m - 41:17 (5:11)

9m - 46:35 (5:18)

10m - 51:48 (5:13)

11m - 56:58 (5:10)

12m - 1:02:14 (5:16)

20km - 1:04:28

13m - 1:07:38 (5:16)

HM - 1:08:02

14m - 1:12:38 (5:08)

15m - 1:17:48 (5:10)

16m - 1:23:01 (5:13)

17m - 1:28:08 (5:07)

18m - 1:33:19 (5:11)

30km - 1:36:36

19m - 1:38:26 (5:07)

20m - 1:43:33 (5:07)

21m - 1:48:44 (5:11)

22m - 1:53:50 (5:06)

23m - 1:59:03 (5:13)

24m - 2:04:06 (5:03)

40km - 2:08:29

25m - 2:09:14 (5:08)

26.2m - 2:15:25

the 3rd mile split of being ~ 8s quicker tallies with her splits

I think it would be for Mo. But let's see what we shall see.

not sure why you are bothering with mo

he's not going to be a factor