Bad Wigins wrote:
20x100 in 15 seconds with 100m jog. Use flying starts and keep the jog fast enough that you don't recover breath or HR, and just slow enough to prevent acidosis.
You will want to give up after 5 reps, but if you keep going you'll realize just how fast you can go operating above sustained O2 capacity (V02max is not your absolute max O2 consumption) and your aerobic system, including muscle fibers, will adapt more quickly than it does to longer, slower repeats.
If 15 seconds is too fast, just hit the 100's in about your 800m goal pace.
Very similar to the diagonals that the Kenyans do.
A good one is 10 x 90 seconds at 2km pace, 90 seconds jog recovery at 50-60% of that pace. You've got to have decent background to be able to do this. So while longer, steadier running might not have much direct benefit for an 800 for example, it gives you the fitness to be able to do these workouts, which do give you more direct benefit.