I've cut nearly a minute off of my 2 mile run time by killing my legs, and my core. A good leg/core workout has always been on my plate at least twice a week. If you're like me, your running sucks after a hard workout involving weights. I usually workout with weights, even while working on my abs, to build strength and muscle endurance. I work with as much intensity as I can muster, to achieve total muscle failure. Once my muscles are good and tired, it's time to run. I can run about a mile after a hard workout before my muscles cry out for mercy, but just for good measure, I'll run one more mile after my body says no mas. If you get to the point where you're able to run with speed after you've reached muscle failure in the gym, give yourself a days rest, and then run when you're fresh, you'll surprise yourself. I don't recommend doing this more than twice a week, 3 times if you're hard core. Just remember to have fun. That's why we do it right?