The ERacePlanner Zone Calculator requires that you enter your Lactate threshold Heart Rate, from which your HR Zones are based. You'll notice that the LT Heart Rate is at the top of Zone 3, meaning that Zone 3 and below are Aerobic (with sufficient oxygen) and Zone 4 and above are Anaerobic.
The easiest method to calculate power zones is to carry out a progressive (step) test on an indoor bicycle trainer, such as a magnetic or fluid trainer (with your power meter fitted to your bike) recording power and heart rate data at progressive workload levels;
1) Warm-up for 10 minutes at a low intensity - less that 50% RPE.
2) Increases in workload will be done by changing to harder gears and/or increasing pedal RPM's.
3) After 10 minutes, increase your workload by 10-20 watts (or by 1-2 km/hr if you have a speed computer) and hold for one minute). Use an RPM value of 90-100, or that at which you would normally ride.
4) During the last 10 seconds of that minute, record your power & heart rate values.
5) Repeat this procedure until you have reached a heart-rate level exceeding Zone 4.
6) You will now have a table from which you can transfer Power values for corresponding HR Zones.
Note: The Zone 5 Power Zone will be the Power level you achieved at the top of Zone 4 HR, and above.
Note: If you already know your LT Power (your power output at Lactate Threshold Heart Rate), you can insert that value at the top of Zone 3, but completing this test will also confirm that value, in a controlled environment.
- Using steps of 10, 15 or 20 watts, will keep the step in the range of 10-20 minutes, for most athletes.
- It is important to be well rested before carrying out such a test, so your pulse responds "normally" to workload increases. Also avoid stimulants such as caffeine prior to the test. Be well fueled and hydrated - a sports drink during the test is also practical.
- Your (power) zones may be 'rounded' to the nearest 10 watt increment - or similar.
- You may test the zones out on the road to confirm they correspond with your RPE and fit the workout descriptions, as provided in ERacePlanner.
Having used a Powertap extensively, you'll be aware of the instantaneous feedback and spontaneous fluctuations in power readings as you shift gears, ride over uneven terrain, and move from seated to standing positions on your bike. For this reason I advice keeping the Zones "practical" for normal use, in terms of their range.
Example: To ride in a 7 watt range (say 146-153) would be extremely difficult to control and the level of concentration required may be extremely distracting and mentally exhausting - in this case I would create a zone of 140-155 or 145-160. Adhering to the wider power zone would still provide the benefits of controlling your intensity by power and maintaining appropriate output levels, for the desired workout or race situation.
This Zone procedure may sound a little unorthodox or "loosely structured" at first, but once you've done the step test and have your Power/HR values in front of you, it will make more sense. Once testing the power zones in training, you'll also agree that a little discression is more practical than a set percentage calculation.
This procedure also personalizes your power zones. A direct percentage calculation may be accurate for one athlete, but way off, for another. This is why we decided to maintain manual entry of power/pace zones in ERacePlanner.
It is very important to remember that as your cycling improves these power zones will change. Your Lactate Threshold Heart Rate value may not change with improved cycling strength, but you will see your "Power at Threshold" - and power at other HR levels - improve, as you adhere to your training program. In that regard, the above mentioned procedure may be used as a periodic test for improvement.
Dave, with my comments above in mind, you may be able to transfer data from your previous VO2 Max test report, directly to your ERacePlanner Power Zone control, but unless the test was recent, the power zones may not reflect your current fitness level. The workload increases in a VO2 Max protocol are usually a little larger, as the physiologist needs you to be strong and powerful at maximum exertion levels.
Please let us know how the test procedure works for you and we'll then delve into some of the benefits of training by power and for those without a power meter; how we can use an indoor trainer and bike computer to gain the same results during winter.
CoachKev.
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