Originally Posted by
livedarklions
I think this misses the mark a bit. The runner is expending energy maintaining his/her upright position, which would not translate to power. I do a lot of elliptical training, and everything I've read indicates that it's nearly impossible to calculate accurately the actual energy expenditure because people vary so much in their muscle usage.
Yes, it's hard to differentiate between power output (which is relatively easy to measure) and energy consumed in producing that power (which is not easy to measure).