RPE/RIR is mental masturbation

Chapters:

00:00 Intro

00:24 New study on training proximity to failure

03:37 Is RIR/RPE even reliable?

07:48 Caveat

08:54 Conclusion

Transcript:

If you train primarily to improve your physique, then using ratings of perceived exertion or reps in reserve is needless over complication in your training programs for two main reasons. First, you probably shouldn’t be leaving reps in reserve to begin with, at least not intentionally. And second, your ratings are not that accurate. Two new studies support these two arguments.

The first new study was a randomized control trial of 46 well-trained men that were squatting around 1.3x bodyweight, on average. Did it a squat specialization program with different proximities to failure. They did not use RPE or RIR values in this case to measure proximity to failure. They used velocity loss, which is very accurate, but a massive pain to set up in practice. Their velocity loss was either 0%, 10%, 20% or 40%. 0% basically was a control group doing only a single repetition, and 40% is training quite hard.

After eight weeks, the data were quite noisy, but they fit with the general trend of multiple recent studies, including multiple by the same Spanish research group: the closer they trained to failure, the more muscle growth they got. Strength gains, on the other hand, were not clearly affected by proximity to failure and seem to peak around 20% velocity loss with a trend for worse gains actually when going to a 40% velocity loss. The latest large scale meta analysis that looked at how close to failure to train came to similar conclusions. As people trained closer to failure, muscle growth improved quite linearly. In this graph you can see that as they stayed further away from failure, so they left more reps in reserve, muscle growth decreased quite linearly.

For strength, however, there was no clear relationship between proximity to failure and strength gains. For strength development a very important caveat is that most of these are very short term studies. In the short term strength development is largely a neural phenomenon. Most strength gains in the short term are not due to muscle growth, but due to improved intramuscular coordination. So your body learns to recruit the existing muscle fibers in a more efficient manner, rather than that it actually becomes better at producing more total raw force.

Engine for muscle growth, if you will, which is muscle mass, still limits long term strength development. So in the long run, the correlations between strength and muscle hypertrophy increase substantially. In the short term they are almost zero, in the long term they become very significant. So a good case can be made that these data underestimate the benefit of training closer to failure for strength development, as it’s clearly beneficial for muscle growth, which drives long term strength development.

Speaking of muscle growth, as you can see in the data, the effect is quite linear. In contrast to the effective reps model, the idea that only the last five repetitions of a set really contribute to effective muscle growth, the data show that many people, many studies, still have appreciable muscle growth when training more than five reps away from failure. However, in practice, if you train very far away from failure, you need to do a whole lot of sets to get a robust stimulus for muscle growth.

If you train closer to failure you need to do fewer sets. And this also explains the entire mechanism of proximity to failure, the effect is entirely mediated by training volume. Meaning, if we equate for repetition volume, so one group trains closer to failure, but they do fewer sets, one group trains further away from failure, but does more sets and ends up with the same total repetition volume – the gains are the same.

Even though the effect of training harder and closer to failure is driven by volume, and not by inherently being closer to failure, it’s still the most efficient to do as many reps as possible within every set. At the very least, it is the most time efficient. In theory, you could leave some reps in reserve and just do more sets, but, you know… Ain’t nobody got time for that.

The second major argument in favor of just doing as many reps as possible with good form is that it’s more reliable. These days, many people think that RPE ratings, ratings of perceived exertion, are the same as RIR ratings, just inverse. So if you have 1 rep in reserve that is the same as an RPE of 9. This is how most people use the scales these days. However, originally RPE was literally a rating of perceived exertion, as the name implies, and it was measured often on a BORG scale of 6 to 20, don’t ask me why they had an absurd scale like that, but that was the idea, and people quickly recognized that a rating of perceived exertion is highly subjective. What some people perceive as high effort is a warm up for others. “Look, you stupid bastard! You’ve got no arms left. – Yes I have. – Look! – Just a flesh wound.”

The solution to the subjectivity of RPE ratings was to invert the scale and basically just make it the inverse of reps in reserve. Reps in reserve are an objective scale but is this scale actually reliable because it’s still an internal estimate that we have to make? A new study found that even well trained lifters with an average of six years of training experience were systematically off in their estimates of reps in reserve. Even when training with only 1 rep in reserve, supposedly, during a set with 70% of their 1RM on squats, they were systematically off by at least 1 repetition.

On average, they were pretty good. Most lifters were only off by 1 repetition, but basically everyone underestimated how much more they could do. And interestingly, the group of trained lifters was no better than a group of untrained lifters doing the same test. Many lifters think that they get better at lifting in general with experience. Unfortunately, this is not true. You get better at doing something with experience and feedback. If you don’t have feedback, you don’t learn.

When we estimate a given proximity to failure and we don’t fact check ourselves by intentionally trying to go past it, we don’t actually learn. We just think it’s five reps away from failure, we assume that we are correct, and that’s what we know down in our logbook. But we don’t actually learn because we never fact check ourselves. The new studies findings are supported by a large scale meta analysis on studies on the effect of training proximity to failure. Trained lifters, on average, are no more accurate than untrained lifters.

The reason that most people think that they get better is probably because they just know how many reps they’re supposed to do. If you have a bench press workout coming up with a 100kg and you know that last time with 100kg you got 8, of course, this knowledge helps you with your RIR estimate. However, you don’t actually become better at feeling it. You just have the literal knowledge in this case. That’s why we see in studies when people do a new exercise that they’re not as familiar with, or they do an exercise with a weight that they’re not familiar with, they’re much worse than we are when looking at their own logbook. Overall, motivated lifters aren’t that bad at estimating their proximity to failure.

I’m not going to tell you that it’s just a horrible estimate and it doesn’t correspond with reality at all. However, the problem is that it gets systematically worse as you get further away from failure. So if you leave one rep in reserve, most people are off by about one repetition. However, when you do a higher rep set, when you do new exercises where you have less information, and in general, when you have more repetitions away from failure, which is exactly when you’re supposed to be using the scale. Otherwise you could just do as many reps as possible again, it gets progressively worse in accuracy.

This is a problem because we see in these studies that the average gym goer leaves some 6 to 7 reps in reserve. If you think that you’re leaving six reps in reserve, in reality that could easily be 10+. I acknowledge that as you get closer to failure, the stimulus to fatigue ratio deteriorates. However, based on these data, I think it’s very clear that the majority of people benefit much more from being empowered and just doing as many reps as possible, rather than worrying about overtraining and worrying about reps in reserve and being accurate, and all of these things. Most people, I think, are best off just training as hard as possible. It is the most time efficient, it is the most reliable, and it is the most simple.

Occasionally training to failure, whether intentional or not, also has the big benefit that it actually allows you to become better at estimating how close to failure you are. You need to fact check yourself, and you need to check that your “as many reps as possible” is actually as many reps as possible, even if you’re not intentionally leaving reps in reserve.

There is one big caveat, and that is lifters that are primarily interested in strength. So powerlifters, Olympic weightlifters, and other pure strength athletes. If you’re training primarily for strength the data are clear that at least in the short term, proximity to failure, going closer to failure specifically doesn’t improve strength development much, if at all, and it does induce more fatigue. So the stimulus to fatigue ratio is clearly worse, and a good case can be made to leave a few reps in reserve. However, beware that if you leave more than 2 to 3 reps in reserve, your estimate becomes progressively worse and most people can do more reps than they think. So your five reps to failure might actually be more like 7 or 8 reps to failure.

Moreover, because strength in the long term is still capped by your muscle mass, it’s still a good idea to just do as many reps as possible, because if it doesn’t hurt strength development and it does improve muscle growth and it is more time efficient, then that’s still a good default argument.

There are also certainly some other niche cases where stimulus to fatigue ratio actually becomes really important, in particular when someone is injured or if someone is doing a really high volume training and they really have to optimize the stimulus to fatigue ratio to even tolerate their volume to begin with. However, as a general rule of thumb, for most people, which is what I recommend, and also what my MH Physique App does is just do as many reps as possible with good form and full range of motion, assuming that you’re using full range of motion in the set to begin with. Doing as many reps as possible and not leaving any reps in reserve is the most simple, the most reliable, and the most time efficient method to gain muscle. I would argue that for serious lifters, tracking accuracy is massively underrated, while for less serious lifters effort trumps everything.

The average gym-goer is better off with simple advice that tells them to do as many reps as possible, as opposed to worrying about reps in reserve, overtraining and other complexities. If you’re interested in a no bullshit, evidence based training and nutrition app, check out the link in the description for the MH Physique App. The link should also be popping up on the screen right about now. See you next time.