Sorry, but the physicist in me wants to do sums. Here is a quick go at calculating the total energy requirements for the Sprint (half Olympic distance) triathlon.
Assumptions
- Swim pace is 1000m in 22 min, which is what I have been doing in the pool.
- Cycle energy requirement is as per my heart rate monitor results (891 kCal, 3.7 MJ)
- Run pace is about 7 minute miles. I add the energy for me running to the equivalent for propelling the wheelchair, which I will assume is a bike for now.
Swim
I have a bit of trouble believing this - maybe that is true for someone with good swimming technique, but I think I do it very inefficiently.
Bike
Run
There is something to add for the wheelchair - using
http://www.gribble.org/cycling/power_v_speed.html suggests that about 20 W would be appropriate, which would be about 0.02 MJ. I think that that calculator calculates work done. If I am only 20% efficient, this would mean that I would need to consume 0.1 MJ to deliver that work.
This gives a total for the run of 1.4 MJ.
Total
- Swim - 0.6 MJ
- Cycle - 3.7 MJ
- Run - 1.4 MJ
- Total - 5.7 MJ
I am quite surprised that it appears that the cycle is so energy intensive compared to the swim and the run. I suppose it will take over twice the time of each of the other activities, which could account for it, but I thought the event may have been designed to balance the disciplines more. It could be that I have used inconsistent calculation methods - maybe the heart rate method for the cycle is over-estimating compared to the theoretical methods for the cycle and run. I think I may become a sport performance geek next.....
Summary
Using my new proposed SI unit of energy, the Mars Bar, the calculated energy requirement of 5.7 MJ equates to about 5 Mars Bars, which is quite a lot of stodge to eat!
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