Weight and race times

20 messages
18/03/2008 at 08:39

Hi, did the edinburgh half marathon on sunday and did it a bit slower than the jedburgh half which i did about 4 years ago when i was a stone lighter.

How much difference is carrying an extra stone going to make to my racing speed ?  Is it going to slow me up by minutes or seconds ?

18/03/2008 at 09:01
Depends on training as well, but if this has been of a similar quality, over a half i would have thought you should knock minutes off.
18/03/2008 at 09:22

Mrs O

 I think they say it's something like 3 seconds per mile per lb of extra weight...but I might be wrong, so best check that.  If so, and everything else is the same, you'd be about 9 minutes slower, I guess.  I expect if the two routes are very different, that may also be a factor in your time.  Also, the weather on the day etc....

18/03/2008 at 09:31

9 minutes for a stone in weight over a half marathon, that sounds like a lot, could be the inspiration i need to lose the babyfat as have been having real trouble getting back to my pre-pregnancy weight and baby is 17 months old now !!!!  So by that reckoning i would have done edinburgh half in 2.05.42 and would have beaten my jedburgh time, pre-pregnancy by 2 mins.

Both courses pretty flat, jedburgh had a wee hill and edinburgh had a bit more wind, so they would probably be similar, also didn't train as well for edinburgh as i had a few colds since christmas (get lots of bugs from darling baby daughter now she is at nursery), so maybe if i had trained better and not had the extra stone i might have shaved off another minute or two !!

18/03/2008 at 09:44

Yup...  thanks to injury I'm a stone heavier than I should be (just under 10st rather than just under 9st) and it makes a massive difference.  Not just to race times (my estimate based on my times its probably an extra 2 minutes on a 5k, an extra 4mins on a 10k and the extra 9 mins on a Half is probably not far off...) - but it also makes a difference to how my joints feel in terms of the impact...  Lighter running is much more pleasant...  but it's slowly shifting...

Edited: 18/03/2008 at 09:50
18/03/2008 at 10:07
on average, 1.8 secs/mile/lb  so a stone is about half a minute per mile, or 7-8 minutes over a half marathon.  obviously there's a normal distribution curve, so you might vary by +-20% on that, or something.  and that assumes that all of the lost weight is fat, or maybe upper body muscle - something not used in running.  if it were a stone of leg muscle, you would probably run a lot slower!
18/03/2008 at 10:33
I wish i'd never started reading this thread - have lost 2.5 stone since i started running but i think i could get another 1.5 off - i'll keep reading this thread for motivation and will power to not hit the biscuit tin!
18/03/2008 at 10:40

Having just shed half a stone, I was about to start a thread asking about the weight/speed thing.

Thanks for starting the thread Mrs O and the info Candy.

18/03/2008 at 10:55


using this page i could have shaved off 8mins 19sec if i was a stone lighter

18/03/2008 at 11:56
According to a table that was published on Runners World site a couple of months ago, 1 stone would equate to just over 6 minutes for a half marathon. I can't find the relevant page now, but I have a print out of it on the wall behind my PC as motivation (1 stone lost so far).
Edited: 18/03/2008 at 11:57
20/03/2008 at 15:36

Surely it depends on what the weight is made up of i.e. is it fat or muscle? If the weight gain is due to increased muscle then this may in fact make you quicker, especially if the muscle is in your legs! Look at Gordon Ramsey...15 stone but does sub 3:30 marathons!

Monique    pirate
20/03/2008 at 16:25
There is a law of diminishing returns once you are under weight though.
20/03/2008 at 16:51

I can plod a 10 mile in 1hr40mins, faster if I feel like it. I recently ran home from work with a rucksack. The 10.5 mile run took me 2hrs 17mins! I weighed the rucksack when I got home and found it to be 11lb.

 I'd say that if the weight was dead (not muscle) then it would slow you down.

20/03/2008 at 16:55

The thought of being under weight -  Oh like that is ever likely to happen to me.

Okay I understand how to lose a stone in weight.  Eat less, move more -  so why is it sooooo hard?

20/03/2008 at 17:58

So to break 2:00 hours in the marathon I need to lose

 4.30 @ 203lbs

 18 minutes per stone (over a mara)  =  116 lbs

 No problem there then. 

21/03/2008 at 09:38

Interesting stuff.  I've only got into running in the last couple of years after years of weight training and football.  I'm too heavily built to be a serious runner and recon I'm carrying about 10kg of unnecessary muscle on my arms, shoulders and chest (for vanity if I'm being honest)

I've done a 77min half and I'm targeting sub 2:45 on my first crack at the FLM but this has made me wonder what my absolute limits are. According to those formulas I could be looking at a circa 2:23 marathon if I quit the weights and shed 10Kg of upper body bulk!!  Surely that can't hold true can it?

21/03/2008 at 21:20

Biscuit tin... did someone mention a biscuit tin... now I have a story abouts biscuits...

I was on a course with a broad bunch of people from my company and I happened to mention I need to stay away from the biscuits at break time. One guy piped up and said that he used to work in biscuit factory and hasn't eaten biscuits since. I asked why, apparently floor sweepings, spit and nasal waste went into the vats. Quite flippantly I said urrgghhh I'll stick to the digestives then (I hope I don't get libelled for this) but he said that he worked for McVities. After a bit more of a chat apparently the practise is quite common even amongst the higher quality designer biscuit manufcaturers.

Now tell me you've just gone off the 3 bourbons you were planning to dunk with your next cup of tea!

21/03/2008 at 22:33
Thanks for that story Craig, don't suppose you have one about Cadburys too.....?
21/03/2008 at 22:42

No sorry but I used to work for an IT company that was right next door to the Bournville site in Birmingham. Some mornings I'd park up and could smell hot chocolate in the air. It was actually quite sickly.

22/03/2008 at 08:58

ah nevermind, willpower shall prevail until the easter eggs have disappeared from my house.

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