Effort v Running

We have a staff relay race after work next Tuesday (who says Actuaries don't know how to have fun?) - 5 x 1km. My team has entered a team of 5, of which I am 1 (and hopefully numbered 2, 3 or 4). Whilst running a single kilometre shouldn't pose me any problems per se (it will possibly the shortest distance I've run since I started running), I will have to do it faster than I normally run. I think to maintain any respect I need to record a time under five minutes. Even this shouldn't be too hard given that did 10km in about an hour in a race last year (ie 6 mins per km)

For some reason though it does seem hard. Despite only needing to increase my speed by 20% (for 5 minutes!) the extra effort is harder than I was expecting. I did a couple of sub 5 minute kms this evening and was really out of breath afterwards. But at least I can do it. And I still have 5 days left for training if I need it!

It did make me realise that there is clearly not a linear relationship between speed and effort. This is probably obvious but I've just not thought about it before:

- If I make no effort, I achieve a speed of zero km per hour and sit on my sofa
- If I make a small amount of effort I'm able to move to the kitchen and make a cup of tea.
- If I double that effort I'll probably make it to the corner shop to get a bag of Jelly Tots.
- Double again and I might start to make a speed of about 6 miles per hour (I'm not sure at which level of effort I switch to imperial units). Actually running now!
- Increase some more and I'm up to today's level. Hard work.
- Increase some more and the extra speed ain't coming.
- Increase some more and I drop dead, heart attack. Back to zero speed.

And that's that conclusively demonstrated. Effort not proportional to speed. Can I have a PhD now?