Thanks,
J.D.
A. Good question. Several years ago, I attended a presentation by the late Ed Burke where he talked about how lactate threshold changes for elite cyclists. When cyclists would begin their training programs at the Olympic Training Center in the preseason, their lactate threshold heart rates were an average of 13 beats lower than when they were in peak racing condition.
To find out about triathletes I contacted Randy Wilber, Senior Physiologist at the Olympic Training Center in Colorado Springs. Randy looked at power output on the bike and running velocity at lactate threshold (LT).
Here is Randy's response:
The data provided is from an Olympic triathlete (three Olympics) as well as a younger, very promising triathlete who is on track to make a future Olympic team. I've provided data for changes observed in LT parameters (Power Output and Velocity) across a single season and quad (span of four years). Listed below are the data along with the definitions for "season" and "quad".
Season: Greatest "preseason" vs. "competitive season" increase within a single racing season within the quad.
Quad: Increase from quad year 1 "competitive season" value to quad year 4 "competitive season" value.
Olympic Triathlete
Season — 10 percent increase in Bike LT Power Output
Quad — 8 percent increase in Bike LT Power Output
Season — 8 percent increase in Run LT Velocity
Quad — 6 percent increase in Run LT Velocity
Developmental Triathlete (novice to cycling)
Season — 23 percent increase in Bike LT Power Output
Quad — 16 percent increase in Bike LT Power Output
Season — 15 percent increase in Run LT Velocity
Quad — 11 percent increase in Run LT Velocity
Randy did not have specific heart rate changes that would have allowed me to compare the triathlete data with the cyclist data that Ed Burke had; however, I am assuming that threshold heart rates changed for the triathletes as well. That written, at some point in the training cycle it is possible to improve cycling power and running velocity with minimal to no changes in lactate threshold heart rate. I don't have specific data compiled on this, but I do see it with the athletes I coach.
So to answer your question directly, yes, I believe your lactate threshold heart rate and lactate threshold speed or power numbers are different in the offseason, preseason and competitive season.
Fine-Tuning Your Training Zones
Should you adjust your training zones?There at least three ways to deal with the situation. The first suggestion is to get tested each six to eight weeks to look for changes in lactate threshold parameters. This can be done at a laboratory or through self-testing. After you receive the results, adjust your training zones and training sessions accordingly.
Some athletes hate the idea of continuous testing and do not respond well to repeated tests. For these athletes, I suggest just two tests. Do one test in the preseason and one in the competitive season. You can also use race data to replace a competitive season test. Adjust your zones twice per season, based on these two tests.
For athletes that have been training and racing for quite some time, I will use their competitive season values to establish training zones that I use year-round.
For these athletes, I consider early-season lactate threshold training as high Zone 2, or low Zone 3. Which zone I use depends on what the athlete did in their transition time between seasons.
As the athlete gets fit I will move the training up into the next heart rate zone. For people that are progressing into the heart of the competitive season, at some point I will move to using specific speed or power numbers for the training session goals, and I'll also track heart rate response for each training session.
To see how the third suggestion works, take a look at the free download documents listed on this page. At the end of the Training Intensities document is a chart to help you figure out your training zones. Let's assume you have a LT heart rate of 175 for running in the competitive season. This places your training zones at:
Zone 1: 148 and less
Zone 2: 149 to 158
Zone 3: 159 to 167
Zone 4: 168 to 174
Zone 5a: 175 to 177
Zone 5b: 178 to 185
Zone 5c: 186 and over
If you are an experienced athlete, I suspect you will track similar to the cyclists and the experienced triathlete mentioned in the studies at the beginning of this column. That means 13 beats (taken from cycling) or 14 beats (taken from triathletes at an 8 percent change applied to heart rate rather than velocity—0.08 x 175). Taking your in-season LT of 175 and subtracting 13 or 14 beats puts your preseason LT at 161 to 162. This is low Zone 3.
If you look at my training plans that include work at lactate threshold (Zone 4 to 5a) intervals, most of the plans have a progression from Zone 3 work to Zone 4-5a. Of course the devil is always in the detail, but this is a general principle.
You don't mention your experience level, but know that inexperienced athletes can expect bigger changes in threshold heart rates and the resulting speed and power outputs. It may take you one or two seasons to hone in on your intensity zones.
No matter which method you decide to use, log the data you retrieve from your training session. Include heart rate response, speed and power data if available. Be sure to include rating of perceived exertion (RPE) data as well. Reviewing your body's response, over time, to the training stimulus you apply is important. If your training is not giving you the results you desire, then something needs to change.