Tanda Predictions for Marathon Times

With the Asics Stockholm Marathon just a few weeks away it’s time to take stock of a few things in my running year.

Although not documented on this blog, I’ve set myself a challenge of running every single day this year (at least 3.2k – two miles in old money). This was loosely inspired by Advent Running and the Tracksmith poster, but the origins are neither here nor there. So far I’ve hit it.

Doing a challenge like that has naturally impacted my traditional marathon build-up. I’ve followed a Garmin plan this time around and on rest days I’ve just done light runs but other than that I’ve tried to stick to tempo or threshold training on the selected session days. The big ‘but’ of all this has been the effect it’s had on my overall quality of session: tempo runs are often on tired legs, intervals are not even harder to complete and the long runs in recent weeks have seen some incredibly slow pace and high heart rates.

To make sense of this, or at least allow me to predict what this might all mean for Stockholm I have been fretting about the long runs in particular. In recent weeks, I’ve hit 32.1, 35, 31.1, 33.6 km each weekend. I’ve done 5 runs over 30k this year and a further 5 over 20k. All of which is much more than I’ve done in the past but I’ve been intentionally running them slower. I’ve tried to stick to Zone 2 Heart Rates, under 140bpm which means around 5:10-5:40 pace per km. It should feel easy but after a while it does fatigue you regardless and it begins to hurt as I run more heavily by slumping into slower cadences and mentally I struggle with the discipline of keeping the HR low especially now the days are 15-20 degrees warmer than those first runs of the year.

Today I stumbled across the Tanda discussions from Christof Schwiening‘s blog which I found via Charlie Wartnaby and the sub 3hr Facebook Group. I printed out this graph and started to plot my weekly distance against average pace to see where I sit. Fortunately, Strava’s log page gives me the weekly duration and distance figures so I did a few calculations on bane.info and plotted 12 weeks’ worth of data. To my amazement it had me sitting along the 3hr 15′ contour and, given the strength of this model, I’m quite encouraged by that.



Black x marks indicate my training weeks


There’s no question that the long runs have really frustrated me, on the days I’ve run slow I’ve wondered how I could even run at paces I was comfortable at in 2015, 2012 and 2011 for the full distance. But then this year I’ve also hit a parkrun PB of 19:03 and regularly go sub 3:45 on my commute runs and in interval sessions. My Garmin VO2 max has been as high as 60 and is currently hovering at 58/59. So I’m fit and, touch-wood, largely injury free. A niggling sciatic nerve, a bit of gluteus numbness and some hints of ITB all might flare up on the day but equally, could not, and if they don’t? Well, to hit 3:15 would be a dream and put me firmly on the road of my 5-year plan to sub 3 with a good opportunity to go quicker in York in October. However, that means averaging 4′ 37″ /km for the entire race and that is a pace which I exceeded for just 25 minutes on Sunday (after 2 hrs 20 mins of slower running). Even with adrenaline and a lighter few weeks ahead I’m not sure I’ve got that in me, and that in itself is a revelation: physiologically the data says I should be able to do it, but my own sense of perceived effort says it’s not.

screenshot-connect.garmin.com 2016-05-16 19-15-52.png

I’ve got time to set that goal, create the pace band and work out what I’ll go at. Keeping an eye on the temperature (average 18 C) and wind on the day will have a bearing but when you’ve spent a fair amount of coin flying out there, hotels and food, do you really want to risk having 4 hours of hell on the road because you took a risk and went out at a punchy pace?

On the 4th June, we’ll know…

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