Rate of perceived exertion, or RPE, was created by “Borg to enable exercisers to estimate the given intensity of cardiovascular exercise on a scale running originally from 6-22.”1. Siff The original scale was 6-22 because the average heart rate is 60-220. The Borg scale as it’s known now is measured in 6-20. This scale equates to the perceived heart rate of the athlete post training by asking them “on a scale of 6-20 how hard was this?” For example on a VO2 max the athlete may answer 16-18 on a scale of 20. When a zero is added to 16, 17 or 18 we get 160, 170, or 180 which is typically around the heart rate achieved during one of these tests. This is a very common answer for a VO2 max test and is a reliable assessment.
Mike Zourdos and Eric Helms have further popularized the RPE scale for strength athletes and in particular power lifting using the numerical scale of 0-10. When we are dealing with the low end of the RPE scale anything below a 5 would be warm up weights or weights that are so sub-maximal for that set that they cannot be graded. Many training systems rely on sub-maximal sets in training to hone in technique and keep bar velocity high and fatigue low like CAT (compensatory acceleration training). Helms has created a single chart utilizing reps in reserve and RPE. For example means RPE 6 = 4 reps left, 7 = 3 reps left. 8= 2 reps left, 9= 1 rep left, 10 = no more reps could have been performed and no weight could have been added. Half numbers like 9.5 meaning more weights could have been added to the bar but another rep could not have been performed.
Below “is a conversion chart based on the mean RIR-based RPE scores reported by the experienced squatters for the single repetition sets at 90 and 100% 1RM, and the 8 repetition set at 70% 1RM in the publication by Zourdos et al.” 2 Helms. Eric Helms of 3D muscle journey has shared this graph from the studies conducted by him and Zourdos that I personally use as a reference chart. The chart works by the lifter performing a given number of repetitions, grading the RPE and then finding on the chart what percentage of a 1 rep max, this number of reps, at this RPE, correlates too on average. For example 5 reps @ 8 RPE is around on average 81% of a lifter 1RM.
Judging RPE accurately means paying attention to bar speed, as we discussed earlier. Bar speed is going to have an individually different look for everyone depending on the athletes body types and levers, exercise being performed, explosive strength VS ability to strain/grind, and if they technically executed the lift well or not. Assuming their form is on point (a major factor) we look at the universal trait in common with all of these potential variables – the velocity of the barbell at its slowest point during the lift. This is the “sticking point” and will be a signature for every individual lifter until they physically change that current sticking point by increasing strength in/below that ROM or they do not change their sticking point because they have adequate strength without disproportionately strong muscle groups. Meaning they just are failing at a leverage point that is the most disadvantageous to them regardless of individual muscular weaknesses. More advanced lifters will be able to grind heavier loads at slower velocities due to increased intramuscular adaptations. “For this reason, the ability to complete maximal lifts at very slow speeds can be viewed as a sign of neuromuscular efficiency, with regard to maximal strength, and indicative of an experienced lifter.”2 Helms. The legendary Chuck Vogelpohl of Westside Barbell knew this fact well and used to claim that incorporating heavy special exercises taught him how to think through a lift while straining. Meaning the bar velocity was so slow he had to optimize his positioning and leverages to place himself in the best position to finish the lift. “Deadlifting with lots of bands on the bar made it very hard and slow, I asked him what this did for him. He said something very important: it taught him how to think while straining.”3 Louie Simmons.
Judging RPE by viewing the slowest part of the repetition allows us to honestly asses the lift. If the lifter takes 2-3 seconds to get the barbell out of the bottom of the squat then the coach or athlete must rate the RPE by how many more reps can be performed with the same or a reduced velocity (accounting for fatigue) out of the hole and/or how much more weight they could add. You don’t rate it a 6 RPE because the barbell picked up velocity at the top and was snappy near lockout, disregarding the fact they had to put considerable effort into the bottom portion of the lift. Or vice versa, easy in the bottom but slow at the top.
Caveat, this is where knowing the lifter or knowing yourself comes into play. Some lifters reps always look slow! From working set weights to 1 rep maxes. So if this is a typical bar speed for that lifter and they can bang out 4 more reps at that painfully slow velocity then the athlete or the coach must know that! This is the individual velocity profile for that athlete and needs to be treated as such. Some lifters have the ability to grind slowly through reps repeatedly while others are highly explosive and as soon as they lose some of that speed and “pop” they miss their lift. All of their reps right up to maximum may appear fast and you may assume they can easily add 20 pounds on the bar, but as soon as they reach that sticking point with a slow enough velocity they miss the lift seemingly out of nowhere.
For example, my bench press sticking point is always around half way up or higher. I know I rely on speed off my chest and use that momentum to push through lockout, as soon as I feel that bar velocity slow down, I know I’m very close to missing a rep. If I go for another rep it may take everything I have (10 RPE) to lock the weight out and finish the lift or I just as easily might miss it entirely stuck in lock out limbo (it’s a weak bencher’s hell). This is an example of knowing myself as an athlete and you must do the same in your own training.
RPE is a great tool to use for major compound lifts and to help with fatigue management. With large compound skill lifts RPE should be kept at 6-8 for the majority of training utilizing 9-10 more sparingly due to accumulated fatigue. Smaller isolation exercises can use RPE as well. Isolation exercises can be taken closer to failure more often. Note that as the reps increase it becomes harder for athletes to guess how close they are to failure and they can often continue to perform repetitions while believing they are closer to failure than they actually are. A good rule of thumb for high repetition work is the further away you are from a 10 RPE the harder it is to know where failure actually is.
Variables in training that may appear with new exercises or executions of exercises like changes in barbells, tempo, angles, drop sets, super sets, the order or exercises, etc. may affect the weight the lifter used to perform with a given exercise previously. They will not have a clear idea where they stand until performing the exercise under the new criteria. Always err on the side of caution for the first couple sets and perform more warm up sets if need be to find the right weight for the day. Apply the same idea to the training block and start off slow as to leave room for improvement. Knowing what to look for (bar speed) and where to look (individual sticking points) will allow you to identify and objectively asses what the next move is in training in regards to bar weight and whether or not that last rep should be attempted.
RPE is a system of communication. It is a language. It is a tool in the tool box. I cannot be there to witness every single rep performed by clients due to distance and logistics. What we can do is watch footage and understand how difficult or challenging a lift and exercise should be on a set per set basis by prescribing RPE ranges and having the athlete communicating back the RPE range that was actually executed for the day. If they went under or over the prescribed RPE range you deal with it on a set by set and week by week basis. That’s what training is. Constant communication and feedback for what is working, while it’s working, and then attempt to figure out and understand why it’s working. I encourage everyone to learn the RPE scale simply by doing. Read the graph and just start recording, it will slowly help you better understand the weight room athlete inside you.
References
- Mel Siff- Facts and Fallacies of Fitness pg. 70
- Eric Helms- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4961270/
- Louie Simmons – https://www.westside-barbell.com/blogs/2016-articles/chuck-v
Pictures
- Borg Scale- http://exercise.trekeducation.org/assessment/borg-scale-rpe/
- Helms- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4961270/
- Sticking Point- https://www.t-nation.com/training/sticking-point-therapy
- Chuck Vogelpohl
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