Couple of tripwires placed appropriately (first on the ground to ensure that they're down at the start, and then the second one block higher and 2-3 blocks away to ensure that they're in the air for the second detection.) Might even want two tripwires at each spot to give them a little flexibility for the launch area and things like that. Main point though is to have the upper tripwire far enough away from the lower tripwire that its unlikely (or preferably impossible) to pick up as a normal walking jump.
Then put a repeater outside of the lower one.. probably only one or two ticks (players move pretty fast when they're sprinting!) and AND the two signals together. If everything is spaced and timed well enough, then you should have a sprinting jump detected when both signals are on simultaneously.
Of course that would be easily broken by just having two players, or a player and a mob or whatever so that each can trigger the other tripwire. Not much to be done for that I'm afraid. Lag may also be an issue if you're trying to build this on a server as some people will move faster than others depending on their individual latency.