The ranges of pace, heart rate, and power for the Alp Fitness training zones are based on percentages of your lactate threshold pace, heart rate, and power, respectively. So, setting your zones first requires finding your functional threshold pace (FTPa), lactate threshold heart rate (LTHR), and/or functional threshold power (FTPw).
Each threshold value — whether pace, heart rate, or power — is sport-specific. Although it’s obvious that threshold pace will be different for running vs. cycling vs. swimming vs. cross country skiing, this is also true for threshold heart rate and power. This is because different activities have different metabolic costs associated with them. So your threshold heart rate for running will be different than your threshold heart rate for cycling, and so on — and the same is true for threshold power. If you train in different endurance sports, this means you should do a sport-specific field test to determine your training zones for each sport.
An important effect of endurance training is to raise your lactate threshold (LT). Whereas before training you could, for example, run a 7-minute mile while at LT, after training the same pace would represent an intensity level below your LT. This means that you are able to go faster at a lower level of effort. In other words, you are able to stay aerobic at that given pace whereas before you moved into anaerobic territory.
Those new to endurance training will see increases in their lactate threshold heart rate (LTHR) as they gain fitness. The LTHR of well trained endurance athletes, however, will remain fairly consistent over time. But the aging process does result in a gradual lowering of LTHR. The best way to stave off the effects of aging is to ensure you’re getting in higher intensity training — this means both threshold workouts and VO2max workouts — rather than spending all of your training time in the endurance zone.
Determining Pace, Heart Rate, or Power at Lactate Threshold
For any activity, exercising at your lactate threshold can generally be done for about an hour. As Hunter Allen, Andrew Coggan, and Stephen McGregor explain, “When power [pace, heart rate] exceeds FTP [lactate threshold], fatigue will occur much sooner (generally after approximately one hour in well-trained cyclists [runners, etc.]), whereas power [pace, heart rate] just below FTP can be maintained considerably longer.”
So, finding your pace, heart rate, or power at your lactate threshold starts with defining what we’re looking for in these functional terms:
- Pace. Your functional threshold pace (FTPa) is the maximal pace you can consistently sustain for 45 minutes to an hour.
- Heart rate. Your lactate threshold heart rate (LTHR) is the maximal heart rate you can consistently sustain for 45 minutes to an hour.
- Power. Your functional threshold power (FTPw) is the maximal power you can consistently sustain for 45 minutes to an hour.
But simply going out and running or skiing or swimming or cycling as fast as you can for an hour is not very practical — unless you’re in an actual race. So, shorter field tests are used to estimate FTPa, LTHR, and FTPw.
Shorter field tests are easier to perform, less disruptive to training, require shorter recovery times, and can be repeated more frequently than hour-long tests. Regardless of whether you’re looking to use them to set your training zones, they also make good benchmark workouts — repeatable workouts on a familiar course that allows you to compare efforts throughout your training year.
Common Field Test Options
Various testing protocols exist, but the options presented in the following sections are the more common ones. They can be done frequently and work well at estimating your threshold values. But since these are guides to estimating your threshold values (rather than precise lab measurements), you may need to adjust your results up or down based on your individual circumstances.
You can use the same sport-specific test to collect data for pace, heart rate, and/or power, allowing you to set zones for the various tools you’re using with a single test for that activity. Below is an overview of the four options presented in the following sections and what they tend to work best for.
The 30-minute time trial can be used to set:
- Pace zones (running, cross country skiing, uphill skimo)
- Heart rate zones (running, cycling, cross country skiing, uphill skimo)
- Power zones (running, cycling, cross country skiing, uphill skimo)
The 20-minute time trial can be used to set:
- Heart rate zones (running, cycling, cross country skiing, uphill skimo)
- Power zones (running, cycling, cross country skiing, uphill skimo)
Race results from a 5K or 10K can be used to set:
- Pace zones (running, cross country skiing)
- Heart rate zones (running, cross country skiing)
- Power zones (running, cross country skiing)
The 1,500-yd/m time trial for swimming can be used to set:
- Pace zones (swimming)
- Heart rate zones (swimming)
- Power zones (swimming)
These options are not exhaustive of the possibilities, so if you’ve used a different test in the past and it works for you, stick with it.
Estimating From One Sport to Another
If you train in different sports, remember that your threshold heart rate and, therefore, your heart rate zones will be specific to each sport. But, if you need to estimate heart rate from one sport to another until you’re able to perform a sport-specific test, here are some guidelines for doing so.
Your threshold heart rate for cycling is typically 5-10 beats lower than your threshold heart rate for running. If you do a field test for either running or cycling, you can use the results to estimate the heart rate zones for the other sport.
For cross country skiing and uphill skiing, threshold heart rate tends to be closer to threshold heart rate for running. But individual variability exists. If you’ll be running and skiing, it’s good to perform sport-specific tests to dial in your zones for each sport.
Remember, the most accurate way to determine your sport-specific training zones is to use sport-specific results. Several options are detailed in the upcoming sections.
