Assessments, Zones and RPE

August 29, 2023

If you train and race in endurance events, you have likely heard the words “zones,” “field assessments,” and “RPE” referenced with training. In this article, I want to refresh your memory on the importance of field assessments, zones, the RPE scale and how they all tie together to maximize your potential. For a deeper understanding of how to complete a field assessment and define zones READ HERE.

Typically, the first few weeks of your training and every 6-8 weeks thereafter, you should complete field assessments. Depending on your goals, these assessments are in the swim, bike and/or run. The goal of the field assessment is to push as hard as you can, maintaining as even of a pace as you can for the duration of the assessment. Ideally, the assessment is completed in the same modality (road vs treadmill, road vs trainer and swimming in the same distance pool), at the same time of day and following the same pre-workout nutrition with each occurrence. This offers reliable data to measure where your fitness initially started, to track improvements over time and to identify specific pace, power and/or heart rate zones to be used with training.

Zones are a way to apply and gauge intensity within your training and each zone is a percentage of your threshold from the field assessment. Depending on the modality, zones will either be set in power, pace, heart rate or rating of perceived exertion (RPE). I don’t typically recommend training solely with heart rate zones; however, it is worthwhile to understand where your heart rate typically sits within each zone. Heart rate can be affected by many different variables and has a somewhat delayed response, which is why you typically should not use this as the only measure of intensity.

Completing these field assessments is crucial to maximize gains. As you improve through your training and increase in speed or power, threshold changes. If you don't re-measure on a consistent basis, your zones may be wrong, possibly resulting in training at too low of an intensity. When training at too low of an intensity, improvements are minimized. While improvements are not always seen every 6-8 weeks (progress sometimes isn't seen for several months at a time) it's still important to reassess, gauge and document the data to know you are on the right track.

This is one reason why it's important to stay within the zones for each segment of your workouts in a well-designed training program. Research indicates generally the best training for endurance athletes to improve both speed and endurance while preventing overtraining and reducing the risk of injury is to apply the 80/20 rule. The 80/20 rule is where 20 percent of your training is done at a high intensity and 80 percent at a low intensity. Keep in mind, not all intensity levels are created equal. What I mean by this is you would never want to include 20% of training at zone seven in your week as your high intensity. Through this principle, and others, your training should be thoughtfully designed, unique and specific to you. You will make the most gains when you stay consistent with your workouts and apply what each workout demands. Focus on each segment of the workout. Push hard through the thresholds and intervals, dial it back on the easy intervals, recovery's and long rides, runs and swims.

When we think of RPE (rating of perceived exertion), this is another measure of intensity, solely based on how we feel. There are several different RPE scales, but the most basic is a scale of 1-10. On a scale of 1-10, one is a minimal effort and 10 is all out, how do you feel? At the end of each workout and within each workout. Each zone holds a specific RPE value, an indicator of how you should typically feel within that given zone. An image of this is above for the bike and run. It's wise to develop a good understanding of RPE to zone. When you're in a workout and hitting heavy winds, running on sand or even pushing a jogging stroller, you will over-reach on your intensity to hit the desired pace, so rather than aiming for that pace, you should aim for the RPE level associated with that pace.

Be cognizant of your fuel and hydration throughout each session and how that may be affecting your RPE. Are you well hydrated and fueled heading into the workout and how did that make you feel and perform? Did you stay well fueled and hydrated during the workout? How did that make you feel and perform? Recognizing the difference and then dialing in nutrition and hydration catalyzes growth.

For women, remember the phase of your menstrual cycle plays a big role in RPE and how your workouts will feel. The week before your period may be rough to find the motivation or you may struggle through the workouts. However, the week of your period, you are at an advantage and higher intensity levels will feel lighter. This is not to say you should keep high intensity workouts reserved for specific timeframes in the month, because you never know what you will get on race day. However, having an understanding of how this affects your RPE and overall outcomes is important.

Developing a good grip on zones and what each zone should feel like on the RPE scale will maximize your gains in training while leading to greater, more enjoyable performances on race day. So, get in the zone, sit in that discomfort and you will soon be stepping into new zones, faster speeds, higher power and greater performances.

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