Powerlifters widely use RPE to quantify how close to failure a set was taken. RPE – or Rating of Perceived Exertion – originates from aerobic training research, but was adapted to use in resistance training shortly thereafter.
As ubiquitous as RPE is within powerlifting, clear guidelines on the best RPE for gaining strength remain elusive. Fortunately for us, a recently published meta-analysis examined exactly this topic.
In their meta-analysis, Robinson and colleagues performed a meta-regression of all available studies on proximity-to-failure and size and strength gains. In total, they included and analyzed 55 studies.
Broadly speaking, there was no relationship between RPE and strength gains. There is one catch, though: this was a load-adjusted model. Since training at a higher RPE, all else being equal, will allow for higher loads to be used, this is worth noting. If you did a set of 5 at RPE 10, versus a set of 5 at RPE 5, all else being equal, you’ll lift quite a bit more at RPE 10. This model accounted for that, because using greater loads does consistently boost maximal strength gains, according to another large meta-analysis.
There’s another consideration to be had with RPE and strength: fatigue. Generally, training closer-to-failure is at least a bit more fatiguing than training farther from failure. In the case of training for strength, this means that training at higher RPEs is more fatiguing, but for no clear benefit.
To illustrate, the same group of researchers performed a follow-up study. Well-trained participants were divided into four groups, each performing the same sets and reps but differing in proximity to failure and %1RM used:
Group 1: Trained with 4–6 reps in reserve (4–6 RPE).
Group 2: Trained with 1–3 reps in reserve (7–9 RPE).
Group 3: Similar to Group 2 but took the final set of each exercise to failure (7–9+ RPE).
Group 4: Trained every set to concentric failure (10 RPE).
Bar velocity was monitored to ensure adherence to the prescribed RPE. All groups met expectations, except Group 1, which trained closer to 8 reps in reserve—more submaximal than intended.
The training program included squats, bench press, and accessory exercises (shoulder press, lateral raises, pulldowns, curls, tricep extensions). RPE adjustments applied only to squats and bench press; all accessory exercises were performed with 2 reps in reserve.
The participants tested their bench press and squat 1RM before and after the training intervention. The researchers also took a variety of measurements of fatigue throughout the study.
Strength gains in squat and bench press were highest in Groups 1 (4–6 RPE) and 2 (7–9 RPE), with slower progress in groups training closer to failure. Additionally, fatigue was generally highest in the RPE 10 group.
In line with their meta-regression, these results suggest that training to submaximal RPEs may be superior to training closer to failure, even in well-trained lifters.
So, where does this leave us? Well, for maximum strength gains, most of your training should probably take place between RPEs of around 5 to 8. This will give you a solid stimulus, allow for pretty heavy loads, while mitigating the impacts of fatigue from training too close to failure.
There are cases where you may be better off training a bit closer to failure, though. Specifically, if you’re in the off-season, and are seeking to fill out your frame to help you out long-term (since, in the long run, gaining more muscle should also help you gain more strength), training a bit closer to failure is wise.
Likewise, if you’re nearing a competition, it’s probably not a bad idea to throw in some high RPE singles (or sets of two to four reps). This will let you lift very heavy loads – which is good for strength – and give you a chance to feel out heavy loads before you head onto the platform. Practicing the skill of grinding out a heavy lift a few times before the meet is likely a good idea.
