Shorter hill intervals of 20 to 90 seconds are great for developing power, strength and speed. Slightly longer intervals of two to three minutes are great for VO2max development. To do a hill intervals workout, warm up with at least 10 minutes of easy jogging. Then run hard uphill for two to three minutes (choose your duration before you start), jog back down to your starting point and repeat.
If your fitness level is modest, start with a set of 4 x 2:00 or 3 x 3:00. Very fit runners can do as much as 10 x 2:00 or 7 x 3:00. Pace yourself so that you neither slow down through the workout due to early fatigue nor finish the workout feeling you could do more.
Lactate intervals are the toughest kind of VO2max training. Make sure you build up a fairly high level of fitness with 30/30, 60/60 and hill intervals before you move on to lactate intervals. It is best to do this type of workout on the track. Warm up with at least 10 minutes of easy jogging and then run hard for 800 (one-half lap) to 1200 meters (1.5 laps) around the track. Now reduce your pace to an easy jog for 400 meters.
Run shorter intervals (800m) in your first lactate intervals workout of a given training cycle and then move upward. Do a total of about 5000m of fast running in these workouts (6-7 x 800m, 5 x 1000m, 4 x 1200m). Again, try to run the fastest pace that you can sustain through the last interval without slowing down.
It cannot be denied: VO2max training is hard. That's why most runners do very little of it. But you're not like most runners, are you? Take advantage of your superior mental toughness and make a commitment to VO2max training. You will find the rewards to be well worth a little heavy breathing.