From: http://www.bicycling.com/training-nutrition/training-fitness/lactate-threshold-101
The following drills are designed to raise your LT. Choose one drill per workout, and do LT training no more than two days a week, preferably not on consecutive days.
Steady State Intervals (the most effective way to increase power at LT)
After a good warm-up, ride 10 minutes at a steady effort, keeping your heart rate three to five beats below your LT heart rate. Recover (ride at an easy pace) for 10 minutes, then repeat two more times. Once you’re comfortable at this level, do two 20-minute steady-state efforts, recovering for 20 minutes between. Eventually, work up to one 30-minute effort.
Up And Down Intervals
These intervals blend LT and VO2 max (your body’s ability to process oxygen) training to simulate the effort you need when racing on a hilly course, where you have to push beyond your lactate threshold for short surges then clear the acid and recover quickly. First, warm up. Then pick up the pace to your LT heart rate and hold that intensity for five minutes. Push it to about three to five beats above LT for one to two minutes, then drop it back down to LT. Continue for a total of three cycles, or about 18 to 20 minutes.
LT Tolerance Intervals
By training at an intensity where your body can’t clear the lactate, you’ll boost your ability to keep riding hard in the face of high lactate levels. After a thorough warm-up, increase your effort to about five beats above your LT heart rate. Hold it there for two to three minutes. Reduce your effort for 60 to 90 seconds, just long enough so you feel partially recovered, but not quite ready to go again. Repeat three times.
