The Basics of Lactate Threshold Interval Training

Lactate threshold (LT) is the primary area of developmental focus for competitive cyclists. It is the best predictor of race performance for many cycling events. Unlike aerobic capacity (i.e., VO2 max), lactate threshold is also highly trainable, which is one of the reasons training zones are often based on LT.

In the simplest terms, lactate threshold is the highest intensity a fit cyclist can maintain for 60 minutes. Any increase in intensity beyond this threshold level requires a reduction in effort because the body starts to produce lactic acid more quickly than it can remove it. The higher your lactate threshold, as a percentage of aerobic capacity, the faster you will be able to ride a bike.

More: What Does Lactate Threshold Mean?

Lactate threshold can be developed in several ways but one of the most effective is through intervals performed at or slightly below your LT heart rate. These intervals will boost your lactate threshold and functional threshold power (FTP), which is the highest average power, measured in watts, you can generate for one hour. Here are some guidelines for performing LT intervals:

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1. Find a relatively flat, low traffic road to perform your intervals. Your route should be free of traffic lights and stop signs. You cannot perform this workout effectively if you have to continuously slow down, stop or turn corners. If you can't find an ideal outdoor route, perform the workout on your indoor trainer.

More: Threshold Workouts to Improve Your Bike Speed

2. Select a gear that allows you to train at 98-105 percent of your LTHR (95-105 percent of your FTP) at a cadence of 85 to 95 rpm during the hard efforts. You can self-select your cadence, but remember that a high cadence with relatively small gearing will place greater stress on your cardiovascular system while big gears with a low cadence will stress your musculoskeletal system. You may want to diversify your training by doing some intervals with a high cadence and others with a lower cadence.

3. Your goal is to build up to 3 x 15 minutes with 5 minutes of recovery between hard efforts; however, this is not set in stone. You can build up to 2 x 20 minutes with 5 minutes of recovery. You can also increase the number of intervals you perform in a workout and make them a bit shorter such as 5 x 10 minutes with 5 minutes of recovery between hard efforts. In addition, you can boost your fitness by incrementally reducing the length of your recovery period from 5 minutes to 2.5 minutes. For instance, you could perform 3 x 15 minutes with 2.5 minutes of recovery between hard efforts for a really intense workout!

More: Does Lactate Threshold Speed Change in the Offseason?

4. Carve out a 12- to 15-week period where you will perform one lactate threshold interval workout per week. During this time, start with 3 x 5 minutes with 5 minutes of recovery. Add a minute each week to progressively overload lactate threshold volume (e.g., 3 x 6 minutes then 3 x 7 minutes then 3 x 8 minutes etc.). As you reach the last two or three weeks, you should arrive at your goal of 3 x 15 minutes. Also, recovery is very important when it comes to lactate threshold training so insert a rest period every three or four weeks (i.e., no intervals that week).

5. Your total workout time will vary between 60 and 90 minutes. Your early efforts will be closer to 60 minutes because your interval lengths will be shorter. Of course, as you increase the length of your hard efforts, total workout time will increase as well.

More: Power Up With Tempo Intervals

6. Theoretically, you can perform lactate threshold intervals year round; however, I recommend you perform them during the intensity and/or competition phases of a periodized training program. In other words, avoid this workout early in the year while you are building your aerobic and muscular endurance, and use it to help prepare for key events as you approach the competitive season.

More: The 3 Cycles of Periodization Training

7. When performing LT intervals, start by warming up for at least 20 minutes. If you currently compete in criteriums or time trials, use your race warm-up to prepare for this session. After your warm up, ride as hard as you can for the target duration of the interval. Remember to keep your cadence between 85 and 95 rpm, and your heart rate between 98 and 105 percent of your LTHR (95-105 percent of your FTP if you have a power meter). Don't overdo it, especially during the first two minutes! This is a common mistake. Slowly build your effort up to your target heart rate and then hold it for the duration of the interval.

More: High-Intensity Intervals: Hurts So Good

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