Conversion Rates From HM to Marathon

TickTock · March 2011

Interesting thread, Male results since turning 40..

2008 Spring     HM 1:27:44 FM 3:11:44 (40)
2009 Spring HM 1:24:53 FM 3:13:33 (41)
2009 Autumn   HM 1:26:54 FM 3:06:53 (41)
2010 Autumn   HM 1:27:51 FM 3:06:34 (42)

Ratzer · March 2011

MS

HM 1'29, M 3'20

Moraghan · March 2011

Thanks everyone. For shits and giggles here are some stats from the women's race 2010 London Marathon:

60 women finished between 3:10 and 3:15.

Of these 34 had run a half marathon in 2010 prior to running London.

The average conversion was HM * 2 + 13:50 or 7.73%.

The data would be skewed to a worse conversion if you considered that many of the HM may not have been all out, however the opposite would also be true if considering the number of runners who went out too quickly (the average split of all 60 saw the second half of the race being about 5:40 slower than the first).

I would expect males to have a worse conversion and, generally speaking, the faster the time band the better the conversion and vice versa irrespective of sex.

Keep them coming - I think the statistical value would be enhanced with a greater sample size however I slept through statistics at University so may be quite wrong. I know the greater the number of people in the bar the more likely you won't go home alone.

Catalin Bond · March 2011

I sometimes wish I was a statistician but went for psychology instead which involves a fair amount of statistics. Agree bigger sample sizes are always good but to increase the generalisibility of the findings here more people with slower times are needed particulary men.

Edited to add with a large enough sample you can do a stratisfied analysis splitting into males and females and also by time bands. Then you can see if your assumptions that females and faster runners would have a better conversion are correct.

Fish52 · March 2011

Moraghan - interested in your conversion formula of 2xHM + 7.73%. In Bruce Tulloh's book 'Running over 40' there is a page with various conversion options, one of which is 2xHM + 7.5%; and all of which give a much more conservative HM to M coversion than any online predictors.

Moraghan · March 2011

shine on.... agreed on all that. Hopefully more people will step forward post Spring marathon.

iFish - thanks for that. Not really a conversion formula as yet, just a reflection of what happened last year! Is 2 * HM + 7.5% the most aggressive of his predictors? To take McMillan (as an example) I've always thought of his conversion as a best case scenario and therefore a fairly unlikely one. For nearly every runner you would take that as a start point and then add on time based on the individual qualitative data.

Obviously the + 7.5% increases the number of minutes the slower the runner, but I also wouldn't be surprised if the % itself grew as times got slower for an unpleasant double whammy (particularly as I still think women running between 3:10 and 3:15 would be among the best converting group).

Curly45 · March 2011

Moraghan wrote (see)

shine on.... agreed on all that. Hopefully more people will step forward post Spring marathon.
iFish - thanks for that. Not really a conversion formula as yet, just a reflection of what happened last year! Is 2 * HM + 7.5% the most aggressive of his predictors? To take McMillan (as an example) I've always thought of his conversion as a best case scenario and therefore a fairly unlikely one. For nearly every runner you would take that as a start point and then add on time based on the individual qualitative data.
Obviously the + 7.5% increases the number of minutes the slower the runner, but I also wouldn't be surprised if the % itself grew as times got slower for an unpleasant double whammy (particularly as I still think women running between 3:10 and 3:15 would be among the best converting group).

Yes definitely, partly due to the fact that the slower runners will be those who have the least speed endurance and you end up with odd conversions like mine where 1/2 + 7.5% would be around 4:10 I think, but 1/2 + 10% would get you much closer to my actual time...

parkrunfan · March 2011

Moraghan wrote (see)

shine on.... agreed on all that. Hopefully more people will step forward post Spring marathon.
iFish - thanks for that. Not really a conversion formula as yet, just a reflection of what happened last year! Is 2 * HM + 7.5% the most aggressive of his predictors? To take McMillan (as an example) I've always thought of his conversion as a best case scenario and therefore a fairly unlikely one. For nearly every runner you would take that as a start point and then add on time based on the individual qualitative data.
Obviously the + 7.5% increases the number of minutes the slower the runner, but I also wouldn't be surprised if the % itself grew as times got slower for an unpleasant double whammy (particularly as I still think women running between 3:10 and 3:15 would be among the best converting group).

I think that could be true up to a point, but it is likely to be related to fitness level rather than absolute times.

By that I mean that your conversion will be tighter the fitter you are, which could mean that a 4 hour runner at the peak of his/her ability after 5-10 years of consistent training is likely to have a better conversion than a 3 hour runner who is still on the early part of the improvement curve with only a couple of years training in the bank.

Another good benchmark for conversions is to take 3x10 mile time as a conservative estimate of your marathon time. This should be used as your 'Plan C' time!

Curly45 · March 2011

Hahaha excellent cross post

Moraghan · March 2011

parkrunfan wrote (see)

By that I mean that your conversion will be tighter the fitter you are, which could mean that a 4 hour runner at the peak of his/her ability after 5-10 years of consistent training is likely to have a better conversion than a 3 hour runner who is still on the early part of the improvement curve with only a couple of years training in the bank.

Yes, agreed - implied in my assumption is that on average the slower the less well trained, which is obviously flawed in many cases. In particular those well trained runners slowing because of age.

parkrunfan · March 2011

Curly45 wrote (see)

Hahaha excellent cross post

Even highlighted the exact same words - spooky!!!

Moraghan - We'll have less of this 'agreeing' business - where would these forums be if everyone did that, eh?

Curly45 · March 2011

parkrunfan wrote (see)

Curly45 wrote (see)
Hahaha excellent cross post
Even highlighted the exact same words - spooky!!!

Moraghan - We'll have less of this 'agreeing' business - where would these forums be if everyone did that, eh?

You have to do that to cut through the waffle

Keir · March 2011

Keir - Male (36)

2010; HM - 87.51, Mar - 3:09:36

"however I slept through statistics at University so may be quite wrong. I know the greater the number of people in the bar the more likely you won't go home alone."

Time of year is also a factor to be considered with that statistic Moraghan. Not a co-incidence that I met my wife in a dark club on the last day of term.

Moraghan · March 2011

Who was most horrified the next morning?

Keir · March 2011

Still waiting to have that conversation. I guess that is how we have ended up married with 2 kids.

kaysdee Kelly · March 2011

Curly45 wrote (see)

You have to do that to cut through the waffle . kaysdee I think you are awesome

You do know you can edit quotes and can delete/chop through the waffle, right?

You and PRF may need to pay attention if you do that to make sure neither of you puts words in the other's mouth .

Fish52 · March 2011

Parkrunfan - Have you got BT's book? 3x10m time is on of the other conversions suggested.

Moraghan - 2x1/2M+7.5% is probably the most agressive. I wrote the post because runners often use the online predictors, which are always too optimistic, unless you're an experienced marathoner with plenty of weekly miles under your belt - and even then nothing is certain.

Funny thing is, it doesn't stop me using the online predictors - and then being way out on the day!

kaysdee Kelly · March 2011

The marathon conversion is the only one I disregard. I still check it to daydream "if only", but would probably always add 5 mins on.

Curly45 · March 2011

kaysdee (Kelly) wrote (see)

Curly45 wrote (see)
You have to do that to cut through the waffle . kaysdee I think you are awesome
You do know you can edit quotes and can delete/chop through the waffle, right?
You and PRF may need to pay attention if you do that to make sure neither of you puts words in the other's mouth .

I know but I dont like to mess with them too much in case it removes necessary context

But you are awesome