Triathlon Lactate Threshold: Interval Training for the Bike

When training for the bike leg of a triathlon, consistent stressing of the body’s lactate production mechanism is the key to achieving a faster race pace on the bike and a smoother transition from the bicycle to the run. If you don’t know too much about the lactate threshold, click here for a previous article on the topic. Unfortunately, it can be difficult to train at lactate threshold for long periods of time, such as the time required for completion of a 40K Olympic distance cycling time trial. This is because the body buffers lactic acid by combining lactic acid’s hydrogen ions with carbon dioxide (for subsequent transport in the bloodstream and removal as carbon dioxide at the lungs). To blow off this CO2 and retain a physiologically normal blood pH, you must maintain a level of ventilation that can be quite difficult. In addition, that acidic burn just *hurts*!

A good approach to this paradox is to spend small amounts of time at lactate threshold. By pushing at the proper intensity for 2-5 minutes, you can gradually increase the body’s tolerance to lactic acid and the body’s ability to utilize lactic acid as a fuel, while training the body to work at higher levels of energy output while producing less lactic acid.

As your lactate tolerance rises, the goal is to eventually “string together” these short lactic acid threshold intervals to produce one long race pace intensity effort. Here’s a sample interval training workout series that will allow you to achieve this adaptation:

Find a trail, route, or road that is relatively flat (occasional rolling hills are OK). Warm-up spin for 10 minutes.

At the first mile marker after completing the warm-up, increase by 2-3 gears and stand to sprint as hard as possible for 30 pedal strokes. This will initiate production of lactic acid.

After the standing sprint, sit and reduce the gearing so that 90RPM or more is possible. Maintain the “burn” in your legs, pushing at 85-95% all the way to the next mile marker. Depending on how fast you’re riding, this will be a 1.5 to 4 minute interval.

As you reach the next mile marker, gear down and maintain the same cadence, working at about 55-65% effort. This is your rest interval, and it will last all the way to the next mile marker.

Repeat the standing sprint to seated time trial effort for the next mile. Perform 4-10 intervals, switching back and forth from lactate threshold to easy pedaling every mile.

Do this workout once per week for 2 weeks. After 2 weeks, choose one of the intervals and perform a 2:1 work rest interval, meaning that you will push hard for 2 miles instead of just 1 mile (on only *one* of your intervals) and rest for the normal 1 mile. So, if you’ve been performing 8 intervals, with eight 1 mile sprints and eight 1 mile rests, you’ll now be performing one 2 mile sprint and six 1 mile sprints, with seven 1 mile rests.

The next week, reduce the interval count, again linking two 1 mile segments together. Continue to keep your rest intervals at just 1 mile.

Continue to “string together” your lactate threshold efforts every week. By the end of 2-3 months, you’ll be able to maintain a much higher race pace intensity, without burning out before the end of the time trial.
Remember to allow adequate rest and recovery after intense interval training, and you’ll see great performance results!

If you want more workouts, or want your entire season’s workouts for every single day of the entire year to be designed based on your personal schedule, limitations, or goals visit http://www.pacificfit.net, and check out the triathlon coaching options, or contact [email protected] for more information.