Couch to 5K
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The accuracy of these calculators

I have been using Jack Daniels racing/pacing calculator for some time now - firstly to know what pace to run at during training runs and secondly to estimate a time to aim at when running a 10K that I was training for ( and completed very recently)

However- my previous PB at Parkrun was 32: 30 and the calculator was telling me that the equivalent race time for a 10K was around 1hour 10 minutes - so I used the training paces to run a 1 hour 10 minute 10K and found them to be challenging but doable. BUT - when I did the 10K , I ran it in a time which was quicker than twice my 5K PB??? Have been wondering how that happened and even suspecting the time that I was given at the end of the race.

Now, after getting a new 5K PB yesterday of 30:34 . I put that into the calculator and get a projected 10K time of 1:03:36 , which is almost exact within 10 seconds!!!! Is all this merely coincidence, magic or Science??? :)

3 Replies

Who cares! They are both brilliant times, so clearly the training paid off!!



There is a lot more magic in the world than we care to imagine. If we took life less seriously we could certainly achieve more.

But in the cold light of day (LED actually) It's because we are just starting out. What you did a few weeks ago is old hat. You are getting fitter every day and it shows. I have gone on Parkrun from 33:22 which I was over the moon about to 29:39 which is magic, in seven weeks.

I predict that if you carry on doing your 10k training, that in a couple more parkruns you'll beat 30 minutes, and doing 10k under an hour should be doable as well.


It's little wonder that your pace isn't right if you've been using Jack Daniels to calculate it. Stick to the water mate!

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