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.
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:
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.
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!