The energy cost of transport - that is, how much energy (note: not the *rate* of energy expenditure) must be expended to transport a given amount of body mass a given distance - is largely independent of running speed, but can and does vary between individuals (+/- 10-15%, maybe), and clearly tends to be lower in runners than in non-runners (e.g., cyclists) or untrained individuals.

IOW, by simply knowing body mass, speed (and grade), and duration, it is possible to come up with a *ballpark* estimate of your total energy expenditure. Such numbers, though, are less reliable than for cycling, but much more trustworthy than for, say, swimming.