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Training Zones and Specificity

Written by Dr. Skiba

The principle of specificity is one of the most important tenets of exercise physiology. It states that the body adapts precisely to the stimulus applied to it. For instance, if you wanted to get better at golf, you would head for the local course and hit a lot of balls. You would not (or at least, should not) believe that playing cricket would improve your golf game, even though this sport also uses your arms.

The cricket/golf example is rather obvious. Interestingly, it turns out that there is very little crossover between sports that share more similarity. For example, in well-trained athletes, there is little cross training effect between cycling and running, even though most triathletes have been brought up to believe otherwise. The logical corollary of this fact is that you must focus on all aspects of your race, and you should avoid the common feeling that an extra workout in one sport somehow makes up for a missed workout in another.

Specificity even applies to the various energy systems we discussed last time. A good rule of thumb might be as follows: To improve a particular aspect of fitness in the most efficient way possible, a workout must stress that aspect as directly as possible. One way of thinking about this is in terms of training zones, which is a concept familiar to most triathletes. The basic idea is simple enough. Each zone is demarcated by a high and low heart rate, power output, or pace, and training carried out within each zone is purported to focus on stressing one particular physiologic parameter (for instance, LT or VO2max).

While there is some factual basis to this conceptual framework, it is important for you to realize that these zones are purely artificial constructs. Each is man-made, and each is an oversimplification in some way. Furthermore, there is significant spillover between zones. For instance, 20 minutes at LT power would be expected to target LT. However, 40 minutes at tempo power might result in similar improvements to LT. Also, you would expect some improvement in VO2max from training in the tempo or threshold zone, even though each might be 10-25% beneath power output, pace, or heart rate at VO2max.

All this said, we could come up with some general guidelines regarding what sorts of workouts ought to target each particular aspect of physiology. Below, you will find a summary culled from several sources, which will give you an idea of where workouts fall on the continuum of physiology. You can find a much more in-depth chart in my book, Scientific Training for Triathletes, which you can refer to if you are so inclined. Another popular reference (although specific to cycling) is Dr. Andy Coggan’s chapter on training and racing with a power meter, which is available online as a free .PDF from several sources.

Recovery:
These workouts fall somewhere around 50% of your pace/power at LT (which you can guesstimate rather accurately by using your best 1 hour power on the bike, or the pace you maintain for a run that is longer than about 10k and less than about an hour). They are primarily to have rest without inactivity, and should not make up a substantial portion of your training regimen. An example might be an hour long, easy spin around the neighborhood.

Endurance:
These workouts might also be referred to as long, slow distance sessions. They focus primarily on the fatigue resistance of the slow twitch muscle units, though they do have some effect on LT and even VO2max. These fall between 65 and perhaps 75-80% of your power or pace at LT. You aren’t putting the hammer down, but you are riding or running with a purpose.

Tempo:
The tempo zone is often referred to as the no-man’s land of training, because it is not easy enough to be easy and not hard enough to be really obnoxious. These workouts fall in the 80-90% of power or pace at LT realm, and it should require some focus for you to remain at the appropriate level. They may focus on your ability to store more carbohydrates, and will tax your LT and VO2max to a greater extent than plain-jane easy riding. An example might be a two-hour ride with 2 x 30 minutes in this zone.

Threshold:
Threshold is probably where you get the biggest bang for your buck, at least in terms of the adaptations that will make you a better triathlete. These workouts will focus on your ability to burn fat and spare your limited carbohydrate stores. These workouts fall around 90-105% of your power/pace at LT, and can be quite taxing. An example might be one of Dr. Coggan’s favorite workouts: 2 x 20 minutes at LT power with a minute or two of recovery between. These workouts will also have a substantial effect on VO2max.

VO2max:
VO2max training is extremely difficult. This zone could be figured in a number of ways: 5 minute power output, about 5% faster than your 5k race pace, or 105-120% of your power/pace at LT. These intervals should only be a couple of minutes in length. They focus on improving the maximal pumping capacity of your heart, and may also help convert muscle fibers from fast-twitch to more slow-twitch characteristics (in other words, making them more fatigue resistant, but able to generate less gross force overall). These intervals are not quite long enough to cause optimal improvement in LT, but will still have an effect on LT.

Anaerobic Capacity:
Workouts carried out at greater than 120% of your power/pace at LT focus primarily on your ability to make short, hard surges. Triathletes should not spend too much time in this zone, unless they are involved in draft-legal racing, or race on courses with multiple short, hard climbs.

Of course, the proper mix of these various training levels is a question that falls squarely in the realm of coaching. However, all good coaching is founded in the principles of exercise physiology. If you are self-coached, take the time to educate yourself in these principles. If you have hired a coach, be sure that he or she is well versed in these matters. You owe it to yourself, and to your competition, to turn up in the best shape possible on race day. Anything less is a waste of your time and talent.

In my next column, I will discuss the limitations of heart-rate based training and the relative benefits of relying on power or pace. Until then, train smart!

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