5k to 10k conversion

Hi all.

I've tried various calculators (runpaces software, mcmillan, fetcheveryone) and got different answers.

I ran 5k in 19:14 this weekend, and have a fairly long-standing target of sub 40 min 10k. Started in back running in Jan with 46 mins, ran 42:25 at Easter. Training has probably been more typical of 10k than 5k.

There are 2 races on the horizon - one in a fortnight and one in November. Both involve a fair travel, so would really only like to do one.

Be interested to know how peoples' times from 5k and 10k compare - the calculators I have used vary from 39:59 (yay!) to 40:36 (boo!). 

Hi EC, I recently ran a 39:49 10k off a 19:10 5k the week before so I would say you are pretty much right on the money.

I guess it depends which race you prefer and which is the quickest course. All things being equal you would probably be about 60/40 to do it in 2 weeks and probably 80/20 in November if you get a solid block of training in.

Good luck!

Probably depends if you have endurance for the extra distance.

I have 5k 18:57, 10k 38:47, and that should equate to a marathon of 3:01....but my marathon PB is 3:21, possibly because I don't do enough distance in my runs.

I reckon you're just about there (other things being equal, blah...) I see one of the predictors is McMillan with 39:57, which is obviously tight but I'm pretty sure the formula they use generates a looser relationship than it used to (i.e. plug in a strong 10k time for me and it will give me a very aggressive 5k target).  Might be worth doing some target pace tempo intervals to see how it feels - see if you can manage something like 4 x 2k or 6 x 1M off 90s recovery.  That'll get your heart going. 

Paul - predictors get a lot less reliable when you go from 5k/10k to 10k/marathon because there are different energy systems being used (working way above threshold vs. below threshold but for a very long time), plus so many things that need to go just right to convert up to the marathon distance.

McMillan gives you some tough times to hit in general when you go longer race to shorter race.

And seemingly gives you too soft a target when you key in a short distance to predict your 10m/half marathon

No idea on marathons...that's a different world of tricky calculations..

Cheers for the feedback guys.

I did a half marathon in July in 1:33:14, on a whim really, without really focusing training on it - longest run was 9 milesbefore it. Got quite a lot of miles in during August (teacher making use of the hols), so think the stamina is there.

Guess I'll give it a go in a couple of weeks.

Cheers.

Good luck Exile - I ran an 18.53 before my first sub 40 (I actually ran 39.59) but then I'm better at shorter distances. I did then go and knock a further minute and a bit off that 10k time the following month. I reckon you have a good chance if it all falls into place on the day.

Stevie – I’m not entirely convinced about the Macmillan bias. What makes you think that? IMO its reasonably accurate overall and I think the times it suggests are good equivalents (i.e. the same standard). Of course the conversion will depend upon what category of runner you fit into and speed/endurance bias. For instance its often the case that for older runners/women it’s easier to hit the longer distance times. But for younger guys who will often have more speed the shorter times are easier to hit than the longer ones.

Exiled, my 5k PB was 19:07 when I broke the 40-min barrier earlier this year (39:46), but that was on a pancake flat course on a perfect day for running. Saying that, my HM PB is a few minutes quicker than yours, but if you've been putting in the miles since your half and your endurance has improved you should be ok. If the race in a fortnight is on a fast, flat course, then I'd go for it as you're just about there. Good luck!