Kraft, J. A., Green, J. M., & Gast, T. M. (2013). Work distribution influences session RPE during resistance exercise. Medicine & Science in Sports & Exercise, 45(5), Supplement abstract number 1229.

This study examined the influence of work distribution (varied load, set, and repetitions) on session-rating of perceived exertion in two resistance exercise trials matched for total work volume and work rate. Ss were tested for one repetition maximum (1RM) on the bench press, lat pull down, overhead press, upright row, triceps extension, and biceps curl. Ss then completed a low-load/high-repetition trial (2 sets x 12 repetitions x 3-minute recovery at ~60% 1RM) and a high-load/low-repetition trial (3 sets x 6 repetitions x 1.5 minute recovery at ~80% 1RM) of each exercise that differentiated work distribution but equated work volume and rate. One warm-up set of 12 repetitions at ~40% 1RM was completed prior to the bench press. A standard 2-minute recovery separated each exercise in both trials. Session-rating of perceived exertion and recovery heart rate were recorded 20 minutes after the exercises were completed.

Pre-set session-rating of perceived exertion and post-set session-rating of perceived exertion were significantly lower for the low-load/high-repetition trial when compared to the high-load/low-repetition trial despite matched total volume and work rate. Pre-set recovery heart rates and post-set recovery heart rates were significantly higher for the high-load/low-repetition trial when compared to the low-load/high-repetition trial. Session-ratings of perceived exertion results indicated the low-load/high-repetition trial was perceived as significantly easier than the high-load/low-repetition trial. No difference in recovery heart rate at 20 minutes post-exercise was observed between trials.

Implication. Session-rating of perceived exertion was sensitive to changes in work distribution and increased with increased load even when total volume and work rate were matched. Significantly higher preset ratings of perceived exertion and pre-set recovery heart rates in the high-load/low-repetition condition may indicate differences in recovery between sets. Significantly higher post-set rating of perceived exertion and post-set recovery heart rate in high-load/low-repetition indicated increased difficulty of individual sets in the high-load/low-repetition trial. Differences in recovery and individual set difficulty likely contributed to session-rating of perceived exertion differences. Differences in session-rating of perceived exertion, despite no difference in recovery heart rate, indicate that session-rating of perceived exertion is sensitive to variation in work distribution but is estimated independently of recovery heart rate.

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