Parts 1-5 of “Power” have outlined what power is, shown the advantages of training and racing with power, described the different types of power metering systems, defined common terms associated with power and explained how to properly set up power training zones.  Now it is finally time to get to the heart of the matter and explain how to train with power. Each power zone outlined in Power Part 5 describes a different physiological system, therefore each requires a different type of training gain adaptation. Here we will outline how to effectively train in each power zone in order to acquire the proper physiological responses for the demand of the event in which you plan to compete.

Zone 1 – Active Recovery 

(Less than 55% of FTP)

Zone 1 efforts consist of easy spinning with minimal effort. The exercise level is too low in and of itself to induce significant physiological adaptations. Zone 1 is typically used for warm-ups, cool-downs, recovery between interval efforts, or to help speed up recovery after a strenuous training day or race.

Zone 2 – Aerobic Endurance (55% to 74% of FTP)

Zone 2 is the classic long slow distance (LSD) training and race effort for most age group Ironman athletes. Sensation of leg effort and fatigue is generally low but may rise at the higher end of the zone or towards the end of a long training session. Zone 2 efforts should build up to, and in many cases exceed, the duration of the event in which you are training for. Because triathlon is an endurance sport it depends heavily on the aerobic system to deliver oxygen and fuel to the working muscles. For this reason, it is the most important physiological adaptation for triathlon. Until this system is fully developed, training in higher zones is of limited value.

Zone 3 – Tempo (75% to 89% of FTP)

Power Zone 3 consists of a moderate effort that usually involves rhythmic breathing and requires concentration to maintain over longer periods of time. This effort is typically “Half Ironman” effort for most age groupers. Zone 3 training is best done with long intervals ranging from 20-60 minutes with 5-15 minutes recovery. They are  intended to improve the athlete’s ability to use oxygen to produce movement. Training at this intensity will increase stroke volume (blood pumped per beat), aerobic enzymes, mitochondria, and capillarization.

Zone 4 – Lactate Threshold (90% to 104% of FTP)

Power Zone 4 will produce a continuous sensation of moderate to hard effort that can be very taxing. This would be considered race effort in an Olympic distance (lower end) or sprint distance (higher end) event for a typical triathlete. Because Zone 4 usually involves labored breathing workouts are usually given in interval form. Intervals given in the 6-20 minute range with recoveries lasting 90 seconds to 5 minutes (about a 4:1 ratio) improve muscular endurance. It’s best to get 20-60 minutes of total “work” time. Training at this intensity will improve your ability to process and remove acid build up, as well as lift your lactate threshold as a percentage of your aerobic capacity. We are not trying to rid the body of lactic acid (or lactate) but rather hydrogen ions which are what is actually causing the burning sensation in your muscles. This is a common misconception and it’s important to note that lactate is actually a beneficial substance used by the body to create more energy.

Zone 5 – VO2 Max (105% to 120% of FTP)

Power Zone 5 training yields a strong sensation of effort and fatigue and is intended to increase VO2 Max. Zone 5 power should rarely be produced during triathlon racing except by elite athletes in very short events. Anaerobic endurance training has been shown to boost aerobic capacity (VO2max), economy, and anaerobic threshold. It typically involves ragged breathing and short intervals. Training this system should incorporate work intervals that are 1-4 minutes long with recoveries that are of equal duration. The typical amount of total work time is between 10 and 30 minutes. Intervals typically last 6-12 seconds or near maximal effort and should include recovery that last 3-5min.

Zone 6 – Anaerobic  Capacity (More than 120% of FTP)

Zone 6 will produce a severe sensation of effort and fatigue. These maximal effort, short intervals are designed to increase aerobic capacity. They are most effective for sprinting power produced in non steady-state events and therefore are of little use to most triathletes. Intervals should be conducted at near maximal effort, typically lasting 5-20 seconds with 3-5 minutes of full recovery.

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Written by Kyle Visin
Santa Barbara Triathlon Club President
USAT Level 1 Coach
Certified CycleOps Power Coach
Co-Founder of KillerTri 

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