Saturday, 3 December 2011

Kepler Challenge

Early in December my project manager Lester and myself travelled to my home town of Te Anau to compete in a mountain run on the Kepler Track. Being one of New Zealand’s Great Walks it is a very well formed track and has stunning views out across Lake Te Anau and deep into Fiordland. Lester did the gruelling “Luxmore Grunt” a 27km trip up Mount Luxmore and back. Having survived the grunt before ,I was slightly more crazy and signed up for the full Monty - the 60km round circuit!

Being an engineer I did a bit of thinking on efficient running and optimal race strategies. I read somewhere that below about 2m/s (7.2km/h) it is more energy efficient to walk. So when I’m going slowly ideally I’ll speed back up (duh) or stop pretending to run and walk for a bit. I planned to use this on any steep hills! If we ignore the moving legs and think of the runner as a rigid body we should try to minimise the acceleration to save energy - so when speeding up and slowing down it makes more sense to do it gradually. The rate of heat generated by a runner must be proportional to their muscle volume. The rate of heat loss must be proportional to their surface area. Hence runners with a lean build will stay cooler at a given ambient temperature... hmm not much I can do about this - hopefully it will be cold? It might be intuitive to keep a constant work output over the whole course. However imagine a course with three sections of 10km each, a runner who can run 10km/h constantly can finish the course in 3 hours. If there is one uphill section and one downhill section most runners will slow down on the uphill and speed up on the downhill. Lets assume that the difference in speed is 3km/h. The uphill section therefore is run at 7km/h and takes 85.7 minutes (25 minutes longer), the downhill section is run at 13km/h and takes 46.2m (13 minutes quicker). So there is a larger effect of not slowing down too much when going uphill than by speeding up for the downhill.

What do you mean I should have gone training more instead of thinking about race strategies? I was discussing this with a phd student working with the NZ cycling team while out running!

Anyhow 6am race day came far to quickly and I was off! I should mention that I had some family competition - both my mother and younger brother were entered in the challenge. My goals were very clear and simple: finish, ahead of Mum. If possible I wanted to cross the line in under 8 hours still able to cartwheel. After being running for a few hours and starting to feel a bit tired it was terrifying to see a sign saying “Only a marathon to go”! Getting off the mountain down to Iris Burn was a relief, until the cramp struck. Apparently my muscles just like staying in their rhythm, I found my steps getting smaller and smaller as the day went on and on. By the end although I could have walked faster than I was running the fear of not being able to start again kept me jogging along.

The drinks stations were amazing, all run by friendly dressed up volunteers. Leppin, oranges and jelly beans were my staples for the day with the occasional bit of chocolate or muesli bar from my bag.

Somehow I made it to the final 10km stretch up the river and that’s when the going really got unpleasant. I was seizing up every few steps and stumbling from tree to tree at points. I couldn’t help but question the motives for finishing, somehow I came to the conclusion that to continue to the finish would allow me to stop moving quicker. I did manage to suck it up and start running for the last few km and yes I did cartwheel over the finish line well ahead of my mother.

So will I do it again? You bet, 6 hours here we come! If you are up for a physical challenge and can devote some time to training I recommend you give it a go!