Originally Posted by
base2
A watt is defined as a unit of expenditure in a certain amount of time. A watt is a watt is a watt.
I think you are meaning: Running requires more watts per mile. If so, that's true & no one disputes that.
But running 8 miles in one hour requires 1000 calories of total energy expenditure. Motivated cycling 1 hour requires the same 1000 calories in the same one hour. Ergo they are the same from an energy expenditure stand point.
The rub is in cycling, it is possible to expend, coast, repeat for a lower total. Cycling can made to be much more sustainable for a much longer period of time. The result is usually more time spent engaged.
Exactly. The amount of energy you expend in either activity depends on both intensity and time. It was widely report that Usain Bolt generated a peak power of 2600W during his WR 100 m sprint. Interestingly top level track cyclists generate 2400-2500W peak power. So in terms of absolute peak power output they are very similar.
But let's have a look at more sustainable power. A 70 kg runner needs to average around 440W to run a 4 minute mile and that would be a serious maximal effort. But a 70 kg elite cyclist would be able to hold 440W for the best part of an hour. So it seems apparent to me that cycling would expend more energy over any sustained length of time.