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RPE vs. RIR: Mastering Training Intensity

A man is training with a barbell in a gym, monitoring his RPE and RIR.
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In fitness and strength training, athletes and coaches use many training principles, methodologies, and systems to optimize performance and achieve specific goals. Among these principles, two commonly discussed and utilized concepts are the Rating of Perceived Exertion (RPE) and Repetitions in Reserve (RIR). Both systems are valuable tools for monitoring training intensity, progress, and fatigue. This blog will delve into the history, comparison, and application of RPE and RIR to help you understand their importance and how to incorporate them effectively into your training.

History of RPE and RIR

Rating of Perceived Exertion (RPE)

The concept of RPE can be traced back to the early 1960s, when Swedish psychologist Gunnar Borg developed the Borg Scale, also known as the Borg Rating of Perceived Exertion. Borg’s research aimed to quantify subjective effort, discomfort, and fatigue during physical activity. The original scale ranged from 6 to 20, with 6 representing “no exertion at all” and 20 corresponding to “maximal exertion.” The scale was later adapted to a 1-10 version, which is now widely used in the fitness industry.

Repetitions in Reserve (RIR)

While the concept of RIR has been around informally for quite some time, it gained prominence in the early 2000s with the emergence of evidence-based fitness practices. As a self-regulated method to gauge training intensity, RIR estimates the number of repetitions one can perform before reaching muscular failure. This concept is closely related to RPE but provides a more objective measure of intensity.

RPE and RIR: A Comparison

Both RPE and RIR are helpful tools for gauging training intensity, but they have distinct differences:

Subjectivity vs. Objectivity

RPE is a subjective measure relying on an individual’s perception of their effort during a workout. In contrast, RIR is a more objective measure, referring to the number of repetitions left in the tank before reaching muscular failure.


RPE can be applied to various physical activities, including aerobic exercises, weightlifting, and stretching. On the other hand, RIR is primarily used for resistance training.

Learning Curve

RPE requires some self-awareness and experience to gauge one’s exertion level accurately. Beginners may need help with this concept initially. RIR, while still requiring some experience, offers a more straightforward approach to gauging intensity, making it more accessible to novice athletes.

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How to Use RPE and RIR in Your Training

Implementing RPE

  • Choose the appropriate RPE scale: Depending on your preference, you can use either the Borg Scale (6-20) or the modified 1-10 scale. Familiarize yourself with the exertion levels and what they represent.
  • Rate your exertion: During your workout, assess your perceived exertion level. Remember that this is subjective, and it may take some practice to become accurate in your assessments.
  • Adjust your training intensity: Use your RPE rating to guide your training intensity. If your goal is to train at a moderate intensity, aim for an RPE of around 12-14 on the Borg Scale or 5-6 on the 1-10 scale. Make adjustments as necessary to maintain the desired intensity.

Implementing RIR

  • Understand the concept: Familiarize yourself with “repetitions in reserve.” This refers to how many reps you could perform before reaching muscular failure.
  • Estimate your RIR: Assess how many reps you have left during your workout before reaching muscular failure. This may take some practice, and being honest with yourself is essential to avoid over- or underestimating your capabilities.
  • Adjust your training intensity: Use your RIR assessment to guide your training intensity. For example, if you aim to train with a higher intensity, aim for 1-2 reps in reserve. If you’re targeting a more moderate intensity, aim for 3-4 reps in reserve. Adjust your workout accordingly to maintain the desired intensity.

Pros and Cons of RPE and RIR

RPE Pros

  • Applicable to various activities: RPE can be used across various physical activities, making it a versatile tool for gauging intensity.
  • Easy to understand: RPE is a straightforward concept that is easy to grasp for most individuals, even those new to fitness.

RPE Cons

  • Subjective nature: RPE relies on an individual’s perception, which can be influenced by mood, fatigue, and motivation.
  • Requires experience: Accurate RPE assessments often require some experience in physical training, making it challenging for beginners to gauge their exertion accurately.

RIR Pros

  • Objective measurement: RIR offers a more objective way to gauge training intensity than RPE, focusing on the number of repetitions left before reaching muscular failure.
  • Straightforward for beginners: RIR is relatively easy for beginners to understand, making it more accessible to novice athletes.

RIR Cons

  • Limited applicability: RIR is primarily used for resistance training and may not be as applicable to other types of physical activities.
  • Requires honest self-assessment: Accurately estimating RIR relies on being honest about your capabilities, which can be challenging for some individuals.

Tips for Successfully Integrating RPE and RIR in Your Training

  • Start with one method: To avoid confusion and ensure accurate assessments, incorporate RPE or RIR into your training rather than using both simultaneously. Once you become proficient in one method, you may experiment with integrating the other if desired.
  • Practice makes perfect: RPE and RIR require practice and experience to become accurate in your assessments. Be patient and give yourself time to learn and refine your skills in gauging intensity.
  • Communicate with your coach: If you have a coach or personal trainer, inform them about your RPE and RIR assessments. This will help them tailor your training program to your needs and progress more effectively.
  • Use RPE and RIR to track progress: Over time, you may notice improvements in your performance, such as completing more repetitions at the same RPE level or maintaining a lower RIR during a workout. These changes can be valuable progress indicators, so track and monitor your assessments over time.


Incorporating RPE and RIR into your training can be highly beneficial for monitoring intensity, progress, and fatigue management. Understanding their history, differences, and applications lets you decide which method best suits your needs and goals. Remember that practice and experience are critical for accurately gauging RPE and RIR, so be patient and give yourself time to learn and refine these skills. With consistent effort and attention, these tools can be valuable aids in your pursuit of improved fitness and performance.

Editor’s note: The content on Base Strength is meant to be informative in nature, but it shouldn’t take the place of advice and/or supervision from a medical professional. The opinions and articles on this site are not intended for use as diagnosis, prevention, and/or treatment of health problems. Speak with your physician if you have any concerns. Please also see our disclaimers.

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