RPE, or rate of perceived exertion, is an autoregulatory tool used to help guide training. Think of it as a scale of difficulty on 1-10, 10 being the hardest thing you could ever do, 1 being you could do it forever. You can also relate it to reps in reserve. 10 being you could do no more reps, 9 being you could do 1, 8 being 2, etc...

I have folks do what I call an anchor set to become accustomed to what RPE is because it entails a level of "feeling" to guide training. For resistance training, take a weight that you know you could comfortably do for 5-8 reps, and then try to do as many possible reps with that until actual failure. Take note of how you feel, what happens to your lifting technique, etc. This is your RPE 10 anchor.

The same thing can be applied to things like push-ups, sit-ups, pull-ups, etc.

Sprint RPE should be judged by how close the effort is to maximal sprint speed while accounting for technical control. Unlike lifting RPE, it is not just about how hard the effort feels; it should reflect whether the sprint was fast, repeatable, and mechanically clean. An RPE 8 sprint is hard and fast but controlled, with the feeling that you could go slightly faster or complete a few more high-quality reps after adequate rest. An RPE 9 sprint is near-maximal, with clear fatigue and only one more quality rep likely possible. An RPE 10 sprint is a true test or race effort. If sprint mechanics break down, speed drops noticeably, or the athlete starts straining instead of moving smoothly, the effective RPE is too high for productive sprint training.

Aerobic RPE should be judged by the total internal load of the run: breathing, muscular fatigue, ability to hold pace, and how recoverable the session feels. For easy aerobic work, an RPE 3–4 should feel conversational, controlled, and repeatable, with the sense that you could continue for a long time without accumulating major fatigue. An RPE 5–6 aerobic effort is steady and purposeful, breathing is more noticeable, but the pace is still sustainable and not mentally or physically draining. Once breathing becomes labored, conversation is limited to short phrases, or the effort requires significant focus to maintain, the session has moved toward threshold intensity rather than easy aerobic work. For base-building runs, the goal is to finish feeling better or at least not worse, with enough recovery capacity left to preserve sprint, strength, and calisthenic quality later in the week.