Rating of Perceived Effort (RPE) is a valuable, validated tool for measuring the effort of exercise. It can be used to determine exercise intensities within and across sessions. RPEs allow for autoregulation, accounting for the influences sleep, nutrition, environment, and other contextual factors have on training. One of the challenges with a 1-10 scale is determining what constitutes a 10. What is maximal effort?
This study assessed two ways of anchoring the upper limit and how they affect perceived effort. An imposed anchor is one based on a provided reference. In this study, they used opening a jar. If a jar was so tight you couldn't open it no matter how hard you twisted, that would be a 10. A self-selected anchor uses whatever reference the participant chooses. They would anchor a 10 to the hardest effort they can imagine. The researchers found the anchors made a large difference in perceived effort.
When performing isometric squat exercises, the mean RPE was 9.4 and 9.7 (non-fatiguing and fatiguing sets) for imposed anchors but only 5.5 and 6.9 for self-selected anchors. For grip, the RPEs were 9.4 and 9.7 compared to 3.9 and 4.5. In all conditions, force production was similar. The simple act of anchoring to an imposed task (opening a jar) made the perceived effort much greater than allowing the participant to self-select. How do you educate a patient on RPE scales and max effort tasks?