Crucible Fitness | Triathlon Training Articles

Training Zones
By Rich Strauss

A heart rate monitor is a very valuable tool for the endurance athlete. For the new athlete, it can act as a rev limiter, placing a limit on how hard you work so that you avoid injury and overtraining. For the more experienced athlete, it can be used to train with greater and greater refinement.

Near the start of your training, you should do some testing to determine your Lactate Threshold Heart Rate (LTHR). You then use this LTHR to determine your training zones. The chart and explanation below are tools to help you better understand and use these training zones. You can use this chart as a guide until you perform your testing and can attach heart rate numbers to these training zones. Or, if you want, you can pitch the heart rate monitor and use this chart exclusively. However, for the longer races, training with a heart rate monitor is a necessity, in my opinion, until you become very experienced.

Training Zone Chart

Zone	Name	Use	Breathing
1	Recovery	Recovery days or between intervals.	Hardly noticeable
2	Extensive Endurance	Long endurance training, base building. Many desirable training adaptations are gained by spending considerable amounts of time in Zone 2. See Base Training for more details.	Slight
3	Intensive Endurance	In general, Z3 is either too hard or too easy and should be avoided in favor of Z2 or Z4-5a. However in early training periods, Base 1 and Base 2, it is sometime unavoidable. Expect this.	Aware of breathing a little harder
4-5a	Threshold	Z5a is your LTHR, and is usually marked by a sudden increase in breathing. Training at or just under this level is extremely useful. Improved lactate tolerance and economy. "Tempo" pace. For the run, this is about 10 secs per mile slower than 10k pace.	Starting to breathe harder (Z4) to breathing hard (5a)
5b	Anaerobic Endurance	Improved lactate tolerance and economy. Useful for Sprint and Olympic training, less useful for Half and IM training.	Heavy, labored breathing
5c	Power	Very short, max effort burst. Not very useful for endurance training	Maximal exertion

Training Zones Explained

A byproduct of the exercise process is lactic acid. At slower paces, your body is easily able to rid itself of this fatigue producing acid. This level of intensity is commonly referred to "aerobic" or "light breathing." As pace increases, so does your body's production of lactic acid. Lactate levels being to increase in the blood, causing fatigue. Breathing becomes labored and so this level of intensity is referred to "anaerobic." Eventually a point is reached where lactic acid is produced at exactly the same rate as your body is able to dispose of it. When measured by your heart rate at this level of exertion, this point is called your Lactate Threshold Heart Rate (LTHR). If you continue to increase your exertion above this point, lactic acid will begin to accumulate and will eventually cause you to fatigue, slow down, or stop. By exposing our bodies to increasing amounts of lactate, we train our ability to process this acid and to resist its fatiguing effects. Pace at all levels of effort is increased and we get faster. Thus LTHR provides us with a convenient measure of intensity.

Now think of your body as a car with an engine and a tachometer to measure its Rpm's. This gauge is numbered from Zone 1 to Zone 5, with the red line beginning at 5 and extending to what we will call 5c.

Zone 1 - Recovery: This is the zone most commonly used during recovery between intervals, or on easy "recovery" days. Intensity is well below LTHR, and your engine is basically idling.

Zone 2 - Extensive Endurance: This intensity is most commonly referred to as conversational effort. Because endurance is most effectively developed and maintained by training in this zone, most long endurance training sessions are done within Zone 2. Exercise in Zone 2 is measured in hours. You are now on the freeway in 5th gear, turning 2800-3000 rpms and going about 75mph, making the long drive to Vegas.

Zone 3 - Intensive Endurance: Because it is neither aerobic (Zones 1 and 2) nor anaerobic (Zones 4-5c), this intensity does not effectively train either energy system. With the exception of early base training, if you find yourself in Zone 3, its is more efficient either move down Zone 2 or up to Zone 4-5a.

Zone 4-5a - Threshold: In this zone, your body is at its maximally aerobic state. That is, this is the fastest you can go and not be anaerobic. Because you are still aerobic, to a degree, you can maintain this pace for several minutes, thus exposing your body to high levels of lactate and maximizing the adaptive response. The needle on your tach is just to the left or to the right of redline.

Zone 5b - Anaerobic Endurance: Training in this zone increases the body's tolerance of high levels of lactate. Because you can only maintain this effort for a few minutes, intervals are the most common Zone 5b workout. During interval training, intensity is maintained for a few minutes in Zone 5b, triggering an adaptive response. We then rest, allow the body time to flush out the lactate, and then repeat the exposure.

Zone 5c - Power: These are extremely short, maximum effort bursts of intensity. Their value to the multisport athlete is limited, with the exception of those severely lacking in force and power.

(Source: "Triathlete's Training Bible," by Joe Friel.)

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