Your question was: What is RPE or "Rating of Perceived Exertion"
Our experts said: The Rating of Perceived Exertion (RPE) is a subjective rating of the amount of exertion someone experiences during an exercise. This measure helps identify the intensity of the exercise. There are 2 types of RPE scales: The Borg Scale and the OMNI scale. Each scale has been used in elastic resistance training studies. Visit www.humankinetics.com to find books on both scales.
View the OMNI scale here.
View the Borg scale here