Extrapolation

An interesting one, this.

I usually do a 10k a week or so before Snowdonia and find that I'm just over a minute a mile slower in the longer event. An international marathon runner who runs 5 minute miles for a marathon could expect to have a 10k time of about 28 minutes, at 4:30 mile pace. Not a dissimilar slowing, in percentage terms to mine.

But then I tend to be something of a one pace runner, so maybe others at my level would deteriorate more significantly. Borne out by me passing lots of folk in the second half.

Probably, the more of a fast twitcher you are, the more you would slow down, as you come to mobilise your white fibres. Also it's going to be affected by your miles. If someones really has done the distance work necessary for a marathon (and just how much is that? I hear you all ask) then there should be less of a slowing effect. If you haven't done the work, you can expect the classic "wheels falling off/all gone pear-shaped/hitting the wall" effect somewhere between 15 and 20 miles, with the consequent drastic impact on pace.

Come on, lets hear about your experiences (JtE, YJ, FSS, Mat); how about a bit of science, instead of my anecdotal viewpoint.

Back to the particular case in question, my prediction is that TF will run almost exactly two minutes and 15 seconds a mile slower at Snowdonia than she will at Sale.

EtU