RPE stands for the Rate of Perceived Exertion - how hard an exercise feels at the time of doing it. It's a subjective measure/rating of difficulty of a set on a scale of 1 - 10 with 10 being the hardest and equivalent to a maximum effort set.
RPE allows us to regulate training based on an athletes current level of fitness, fatigue and performance - a valuable tool that percentage-based work alone often falls short on. It's often used in conjunction with Reps in Reserve (RIR) - another similar method of determining effort levels whereby an athlete estimates how many reps they had left in the tank.
This chart from Reactive Training Systems helps visualize the RIR method of RPE. (Source: https://articles.reactivetrainingsystems.com/2017/12/05/how-to-use-rpe-in-your-training-correctly/)
RPE is applied to a set and rep range. For example, if an athlete was programmed 4 X 6 at a 7-8 RPE, they would need to select a weight that allows them to do between two and four more reps than the set requires. RPE can also be used on time-based movements, but RIR won't be used and the definitions of the RPE scale are adjusted slightly to fit the movement.
Can I change load every set? Yes in short we want you to stick to the designated RPE within the sets if that means your 3x5 @ RPE 7 is 1st set: 120kg 2nd set:115kg 3rd set: 115kg. However if your coach is after a 7-9 then the weight should stay the same throughout. This often is answered initially as a no for complete beginners to RPE as too much variation can often cause a bit of confusion at first. And simplifying the method initially allows for a complete dial in on the understanding. If your coach has you doing progressive sets of 6-9 this could mean an increase of weight each set to hit the RPE but bare in mind of accumulative fatigue as the reps go on.
How to gauge RPE
Gauging RPE to begin with is sometimes a case of progress, not perfection. If an athlete can't rate RPE perfectly, they can still benefit from the thought process. Plus they'll get better with practice. Focus should be on the set and technique - rate the RPE once the set is done. If an athlete decides that a set is an RPE 8 at the time they shouldn't change it when looking back at it as they'll have the best idea of how hard they worked right after their set. RPE isn't based solely on feel and isnt entirely subjective, it's based on both perception of effort and performance of a lift i.e. a set may have felt like an RPE 7 for an athlete but form breakdown, and bar or body speed decrease may warrant it being classed as an RPE 8. On top of this, an RPE 7 for one athlete may look entirely different to another athlete's RPE 7.
It’s worth noting that over time an athletes ability to gauge RPE correctly will improve as they'll have familiarity with how a certain RPE on a movement feels.
Benefits of RPE
Allows precise communication for recording effort levels. It’s more precise than saying “easy weight” or “that felt heavy”.
Allows for autoregulation of load used. This means it allows for the load on the day to be adjusted to fit an athletes performance. If an athlete is getting stronger faster than expected, their coach can take advantage of this by increasing the load. If an athlete is having a bad day or isn't well recovered, the weight can be adjusted down to accommodate.
Allows for an estimated 1RM (e1RM) to be calculated. This is a really useful way to gauge progress during a training cycle as well as find out what types of training athletes respond best to.
Drawbacks of RPE
It’s difficult to rate low-RPE sets precisely. Because of this, it's sometimes easier to opt for a percentage based system for lower effort sets to ensure consistency.
RPE relies on honest assessments. If an athlete can’t rate it honestly because they have too much of an ego, then it won’t work until this is addressed.
RPE functions better when there's a familiarity with the movement - i.e. if you know what an RPE8 feels like on a squat you'll likely have more accurate records of effort.
Custom RPE Customised RPE charts can be used as a gauge or tool to determine target load. This can help accurately track progress of their lifts over time and calculate e1RMs.
In summary, RPE is a powerful tool for recording effort and intensity in training, tracking progress, and predicting 1RMs.