RPE (Rate of Perceived Exertion) is a subjective scale used to measure exercise intensity, particularly in strength training. It helps athletes gauge how hard they are working during a set based on personal perception of effort. The scale typically ranges from 1 to 10, where 1 represents minimal effort and 10 represents maximum effort, or the point of failure where no more reps can be completed.
In strength training, RPE is useful for adjusting training loads, monitoring progress, and ensuring workouts are appropriately challenging. For example, an RPE of 7 indicates the lifter feels they could do 3 more reps before failure, while an RPE of 9 suggests they could only complete one more rep before failure.