Here we have a strong sample workout that can be adjusted in distances by as little as 200 meters per interval to as much as 2 miles. This is going to be abs and running period and if you are not in decent shape, drop two intervals and/or add recuperation time. You otherwise may be hurting all day or throwing up.
Ok this is an up then down pyramid with leg raise ab exercises. I have a video but it needs to be modified. At the top of the motion you need to thrust your legs up to raise your hips off of the ground and you need to do these as if you would with a partner, alternate your core movement medially and laterally. Basically, switch left to right and do 20-30 reps. The running is 400-800 meters, then a mile, then 2, then 3/4 ths of a mile and then an all out 400. Do the abs in between and take 5 minutes in between. This should be damn close to race pace or faster if you base it off of longer races.