Proximity to Failure and Total Repetitions Performed in a Set Influences Accuracy of Intraset Repetitions in Reserve-Based Rating of Perceived Exertion

Abstract

Zourdos, MC, Goldsmith, JA, Helms, ER, Trepeck, C, Halle, JL, Mendez, KM, Cooke, DM, Haischer, MH, Sousa, CA, Klemp, A, and Byrnes, RK. Proximity to failure and total repetitions performed in a set influences accuracy of intraset repetitions in reserve-based rating of perceived exertion. J Strength Cond Res 35(2S): S158–S165, 2021—The aim of this study was to assess the accuracy of predicting repetitions in reserve (RIR) intraset using the RIR-based rating of perceived exertion (RPE) scale. Twenty-five men (age: 25.3 ± 3.3 years, body mass: 89.0 ± 14.7 kg, height: 174.69 ± 6.7 cm, and training age: 4.7 ± 3.2 years) reported to the laboratory. Subjects performed a 1 repetition maximum (1RM) squat followed by one set to failure at 70% of 1RM. During the 70% set, subjects verbally indicated when they believed they were at a 5RPE (5RIR), 7RPE (3RIR), or 9RPE (1RIR), and then continued to failure. The difference between actual repetitions performed and participant-predicted repetitions was calculated as the RIR difference (RIRDIFF). The average load used for the 70% set was 123.10 ± 24.25 kg and the average repetitions performed were 16 ± 4. The RIRDIFF was lower (RPEs were more accurate) closer to failure (RIRDIFF at 9RPE = 2.05 ± 1.73; RIRDIFF at 7RPE = 3.65 ± 2.46; and RIRDIFF at 5RPE = 5.15 ± 2.92 repetitions). There were significant relationships between total repetitions performed and RIRDIFF at 5RPE (r = 0.65, p = 0.001) and 7RPE (r = 0.56, p = 0.004), but not at 9RPE (r = 0.01, p = 0.97). Thus, being farther from failure and performing more repetitions in a set were associated with more inaccurate predictions. Furthermore, a multiple linear regression revealed that more repetitions performed per set was a significant predictor of RIR prediction inaccuracy at the called 5 (p = 0.003) and 7 (p = 0.011) RPEs, while training age (p > 0.05) was not predictive of rating accuracy. These data indicate RIR predictions are improved during low to moderate repetition sets and when there is close proximity to failure.

“Just one more rep!” – Ability to predict proximity to task failure in resistance trained persons

“…The internal meta-analysis echoed the results of Experiment 2, excluding a zero effect and suggesting that participants under predicted. These results are mostly in line with previous findings (Steele et al, 2017a;Hackett et al, 2012;Hackett et al, 2016;Giessing et al, 2016a;Giessing et al, 2016b;Altoé Lemos et al, 2017;Zourdos et al, 2019). In contrast with prior research however, this study to our knowledge is the first to examine this predictive ability during the gestalt experience of RT task performance (where participants attempted to get as close to, but not reach MF i.e.…”

“…The overall results of these studies suggest that participants generally under predict the number of repetitions they can perform to MF whether predictions are made a priori to initiation of the exercise, or at varying degrees of proximity to actual MF. Indeed, Zourdos et al (2019) found that, despite improved validity of predictions with closer proximity to MF, participants still under predicted when they thought they were 5, 3, and 1 repetition away from MF (difference between predicted and actual of 5.15±2.92, 3.65±2.46, and 2.05±1.73 respectively). In the current study, participants were instructed to perform a single set to either sdRM or MF without making prior predictions or a repetition target whilst using a deception design.…”

“…Thus, in a sense, their ability to accurately perceive their effort as being 1 'repetition in reserve' (Helms et al, 2016) was examined. With the exception of Zourdos et al (2019), prior studies have not examined this context where it might be expected that predictive ability would be improved with greater proximity to MF. Furthermore, RT experienced (>1 year) participants were chosen following prior suggestions that subjects' predictive ability may improve with training experience (Steele et al, 2017a;Helms et al, 2016).…”

“…Indeed, there is some suggestion that prediction might be greater when using heavier loads, and thus where fewer repetitions are possible such that any given repetition is closer to MF than with lighter loads (Altoé Lemos et al, 2017;Steele et al, 2017a). However, only one study has examined varying proximities to failure (Zourdos et al, 2019), and indeed predictive ability when participants are attempting to get as close to, but not reach, MF. As noted, Steele et al, (2017b) have previously defined this as the sdRM.…”

“…As noted, Steele et al, (2017b) have previously defined this as the sdRM. Zourdos et al (2019) examined the validity of predictions of 5RIR, 3RIR, and 1RIR. They found that accuracy improved with proximity to MF (difference between predicted and Pre-print article (not peer reviewed) published on 24/05/2020 (doi: 10.31236/osf.io/af6dv)all authors confirm they are happy to share this work 6 actual of 5.15±2.92, 3.65±2.46, and 2.05±1.73 respectively), but that participants were still inaccurate even when only ~1 repetitions away from MF.…”