Rating of Perceived Exertion
As far as subjective scales go RPE is most widely used. The rating of perceived exertion is a scale from 1 - 10 where an individual will rate the perceived difficulty of their set or exercise.
Proximity to failure is the most common approach to RPE implementation. The RPE value will correspond with reps left in the tank or reps in reserve (RIR) after the cessation of a set or exercise. For example, if one were to rate their set a RPE 6 they would have 4 reps in the tank.
Simple equation to calculate RPE:
10 - RIR = RPE RATING
Physical sensations that can have an effect on RPE are increased heart rate, increased breathing rate, increased sweating, and muscular fatigue.
At RPE 5 or below, the likelihood of accurately assessing reps remaining decreases significantly, so we recommend using the scale at or above RPE 5.5.
Percentage Based Training (PBT)
Ten years ago, autoregulation in strength training was much less common. PBT was the traditional approach to individualizing programming. PBT involves implementing training intensities based on a percentages of a tested 1 rep max or a projected 1 rep max.
The drawbacks of percentage based training are that changes in daily performance aren’t accounted for per session. Even though percentage based training has limitations, it is still a highly effective tool to implement.
Video footage can be used to visually examine the speed and quality of the set. Video is most valuable when RPE and footage is logged together to measure technical progress, ease of execution, and performance.