Michael Bradley of the US team leads all athletes in "distance covered" during the group stage of the 2014 World Cup with 38 km (23.6 mi) in 270 minutes of play. That's about 8 mi per game (90 min), for an average speed of 5.33 mph.
How much more calories does football (soccer) burn per mile compared to running? Is it considerably more exhausting than running for 90 min straight at 5.33 mph?
I would think yes, considering Bradley and other players are in fact sprinting and resting (more tiring, I think, than medium-distance jogging), plus constantly shifting directions, which I assume requires more calories than running straight ahead (citation needed).
But is the "distance covered" metric measured this way actually analogous to running? Is 8 miles on the soccer pitch equivalent to some greater distance on a racetrack? What's the conversion rate for "distance covered" in soccer vs. running?
How much more or less calorically expensive is soccer than running?