As a triathlete, it seems we all have an addiction for reading up on the sport, whether it be on the Internets or in those papery substances that historians talk about on the Internets (I think they used to call them “books”). If there was only one book that you were allowed to read as a Triathlete, I think it would have to be the Triathlon Training Bible, by Joe Friel. (He actually just released a new updated 3rd edition this past month. If you already have the second edition, you can purchase just the comapnion edition which is a shorter version with only the new changes.) It contains tons of useful information about the sport, from coming up with a training plan, to determining what to eat during a race, and a ton of other topics. One thing he covers is how to determine what your training zones are, which are useful for knowing how hard to go during a workout.

Since training for Cyclocross begins in earnest next week (woohoo!), I figured it would be a good idea to get an accurate idea of what my training zones are in order to get the most out of my workouts. It had been a while since I last tested (ok, over a year) so I pulled out my copy of Joe’s book to brush up on the test. The recommended way to determine your training zones is actually by using a power meter, but since I don’t have $1,000+ to drop on one right now (I’ll gladly take a donation though ;)), that’s not an option. There is an alternative way to determine training zones by using your heart rate. It’s not quite as accurate as using a power meter but it will work for 99% of us out there. By performing a time trial in a controlled setting, we can determine what our lactate threshold is, and from there, determine our training zones.

“Why do we care about what our lactate threshold is?” or “What is our lactate threshold?” you ask? Excellent questions. Lactate acid is one of 3 limiters of endurance athletes (along with loss of carbohydrates/fuel and fatigue of muscles). As muscles work, they break down carbohydrates and lactic acid is produced as a byproduct. This seeps out of the muscles into the bloodstream and after combining with hydrogen, we end up with lactate. The body is able to remove lactate from the bloodstream and does so continually. As we exercise at low level of efforts, the body is able to remove the lactate as it is produced. However, at some higher level of intensity, we reach a point where more lactate is being produced than the body is able to remove from the bloodstream. This point is known as our lactate threshold. We also use this critical point as the marker from where our workouts go from aerobic (fairly easy and can be done for hours with appropriate fitness) to anaerobic (harder workout, labored breathing, can not continue at these intensities for hours).

With that knowledge, we can now go about to actually determining our lactate threshold. Using a heart rate monitor, you should perform a 30 minute time trial on your bike. It is ideal to do this on a flat road or a trainer/rollers. Begin the time trial, and after 10 minutes, hit the lap button on your watch. After 30 minutes have passed (20 minutes after hitting lap) stop your watch. Your average heart rate for those last 20 minutes of the time trial is a very good approximation of your lactate threshold. Now that you have this number, you can get very good estimations of your training zones (For those of you with the Triathlon Training Bible, you can use the table on page 42 to determine your zones). Again, it is worth pointing out that using a power meter would be more accurate for use of training zones, but for us common people, lactate threshold measurements will do!

I started the first 10 minutes of the ride in the 3rd chainring on my bike, and once I hit 10 minutes, hit the lap button and dropped down to the 4th chainring. I wasn’t sure if I would be able to hold this for the length of the time trial, but figured I had to give it my all and give it a go. I was able to hold this fairly consistently with a cadence of 90 for the length of the ride. When 30 minutes rolled around, I was eager to stop as I wasn’t sure how much longer I could hold that pace. After uploading my data to Garmin Connect (here it is) I found out that my average heart rate was 166bpm (with an average pace of 20.3mph). This gives me my training zones of:

         Zone 1 – 109-134
         Zone 2 – 135-148
         Zone 3 – 149-154
         Zone 4 – 155-165
         Zone 5A – 166-169
         Zone 5B – 170-175
         Zone 5C – 176-181

Once cyclocross training begins next week, I’ll use these numbers to ensure that I’m not going too easy or too hard for each workout. I plan on retesting every 4 weeks, during my “recovery” week, to see how my training is progressing and to adjust intensity levels for the next block of training. I might not post about each of my tests, but I’ll be updating the Performance Baselines section on the right with the latest numbers, and keeping a running history of all my baselines on my performance tests page.

One interesting thing will be to see how exactly my fitness does increase in these tests. I’m unsure whether I’ll see my average pace increase from 20.3mph, or my lactate threshold rise from 166bpm, or some combination of that. Once I’ve done a few and had time to study the numbers, I’ll be sure to let you know my thoughts on the issue! However, as with most things, I’m sure the results will vary by person so my findings might not be directly applicable to you!