2010 - 10km < 38 minutes + 5km < 18 minutes (Read 3869 times)

I know there are a few other threads around like this - sub 18:36/sub 18 and converting marathon to shorter distances but they are on multiple sites. If people want to continue these threads I happy as less work for me. But I know that a number of runners have these or similar goals and I thought that if I could combine them for a new year of 2010 it would be easier to keep track of.

Dwane

You can put me down for both of those though my real goal for 10K is <37min.  I know my racing doesn't show it  but 37 is definitely doable with some work.

A 17:59 5K is MUCH more difficult than a 37:59 10K.  I think the equivalent 10K performance to a 17:59 5K is about 37:21!

Wow, good stuff there Jim.  You must have some kind of trick XL spreadsheet to do the calculations for all three equivalent calculators, eh? 

I used your spreadsheet to come up with my equivalent (though I eye-balled the average of the three)! 

A 17:59 5K is MUCH more difficult than a 37:59 10K.  I think the equivalent 10K performance to a 17:59 5K is about 37:21!

Ah, but are you forgetting that most people lack the endurance to run 'equivalent' times at longer distances?

Then there's the fact that no one said all goals should be equally difficult. And the fact that nice round numbers sound better.

Well anyway, count me in because I had these two goals in 2009 and didn't come close. I will try again in 2010, but will have to focus on them after Boston this April.

 

It seems that at least 80% of those who post on forums are way off on equivalent times.

Being part of that 80% this is something I've given some thought to and I don't believe that the obvious explanation (lack of endurance) tells the whole story. I'd be interested to see a similar analysis for other people but here's how I look at my own results for last year.

5k PR 18:06 (age grades at 78.33% for me) predicts a 10k of 37:40

10k PR 38:27 (age grades at 76.75%)

Both nice performances I'm happy with but there's definitely a discrepancy there. A big discrepancy, my 10k was 47 seconds slower than it 'should' have been. So I need to work on my endurance more?

Here's some more data. Last year I ran fifteen 5k races and one 10k race. (I'm excluding a couple of cross country/trail type races). I had 15 shots at a good 5k performance and 1 shot at a good 10k performance. I ran pretty much a full effort in all these races.

As I see it there's at least three explanations for the relatively better 5k performance:

1) Purely statistical - if you buy fifteen lottery tickets every week at store A and one at store B then the fact that you win more often at store A doesn't make it luckier.

2) Mental - the more you run a distance the better you get at pacing. The more you run a course the better you get at it - not just because you are getting fitter but because you know all the little ins and outs, how fast you need to go at the start to stay out of trouble, how to take the turnaround cones etc

3) Physical - maybe I'm just better at shorter distances for whatever reason.

It's hard to disentangle all these  but we can try and factor out 1) by comparing like with like. Instead of comapring my best performance at each distance compare the median. (I used the median rather than the mean because the median is much less sensitive to outliers than the mean and usually better represents a typical value - it's the number that half the values are bigger than and half are less than. My 10k median is easy, there's only 1 data point. If I rank my 15 5k times I get:

18:06

18:09

18:14

18:18

18:22

18:22

18:23

18:24

18:26

18:26

18:27

18:30

18:33

18:33

With a median of 18:23 - 17 seconds slower than my PR. Note also how the median is a much more 'typical' value - I actually had almost half my runs in a 5 second span from 18:22 to 18:27. If I picked one 5k race at random chances are it would be in this region. Note how the 18:06 'PR' is kind of lonely with only an 18:09 to keep it company. These were days when everything went right - good weather, felt good, didn't get boxed in at the start and perfect competition later on pushing me hard at just the right times. Chances of all these happening together are slim. Much more likely you get two or three out of four giving me an 18:23 or an 18:27.

18:23 5k predicts a 38:16 10k  (remember my actual 10k was 38:27 and my predicted was37:40).  The statistical explanation alone therefore explains 36 out of the 47 second discrepancy (that's over 75% of it). So, for me at least, there's really no need to explain this discrepancy as anything much more than a statistical artifact.

I have nothing against calculators/predictors - I think they can be very useful when used correctly (I like to believe I can run a 37:40 if it all goes right) but I'm sure I'm not the only one who runs many more 5k's than 10k's. I'm not suggesting we all go over to quoting our median times (!) but it's an interesting way of looking at things.

John

Well I would never argue with the likes of Jim, Ken and Dakota (too much experience, kilometres and racing )but there is definitetly something that seems to make a sub 18 5km more likely than a sub 38 10km.

Interesting debate guys, and I'm sure a lot of individual characteristics come into play.

But I'm also surprised that some of you would find the prospect of sub 18 more likely than sub 38.  I personally feel totally the opposite.  It could be a mileage thing but it doesn't seem to be the major factor to me as most people associated with these two goals are clocking 2000 miles a year and significantly more in some cases.

I reckon it's a lot more to do with types of training people do and natural abilities in particular events.

John's times match up well considering the amount of 5k's to 10k's he ran last year, and of course running 5k's week in week out is about as specific 5k training as you can get, giving his 5k performances the edge.

Dwane, I would hazard a guess that you do a fair amount of 5k or faster interval work, which is going to give you a significant performance edge in the 5k, over the 10k.  It strikes me that weekly stamina intervals (10k, 15k and half marathon paced) would probably pull your times closer in line.

I'm personally the opposite, I do a lot of stamina work and virtually no 5k paced work or faster (apart from a few striders).  So as an example I reckon I'd probably be able to run a 36:20 - 36:30 10k tomorrow but probably only a 17:45-17:50 5k, if that.  I'd need to do some weekly V02 work for a month to get my times to match up more accurately.