Effects of rest interval length on rating of perceived exertion during a multiple-set resistance exercise

This investigation analyzed the effect of rest interval length on the rating of perceived exertion (RPE) during a resistance exercise session. Nineteen males performed two experimental sessions: resistance exercise with 30-sec. rest intervals (E30) and 90-sec. rest intervals (E90). In both sessions, five exercises (bench press, knee extension, seated row, knee curl, and frontal rise) were performed at 50% 1RM in three sets of 12, 9, and 6 repetitions, respectively. In the E30 session, the RPE increased between sets in all exercises, while in the E90 session, the RPE increased from the first set to the second set in three exercises. RPE in the E30 session was higher than that in the E90 session in the third set. The results suggest that RPE increases for shorter rest intervals than for longer rest intervals. Therefore, the RPE could be considered an indicator of muscle recovery during resistance exercise.