Ability to predict repetitions to momentary failure is not perfectly accurate, though improves with resistance training experience

Abstract

‘Repetitions in Reserve’ (RIR) scales in resistance training (RT) are used to control effort but assume people accurately predict performance a priori (i.e. the number of possible repetitions to momentary failure (MF)). This study examined the ability of trainees with different experience levels to predict number of repetitions to MF. One hundred and forty-one participants underwent a full body RT session involving single sets to MF and were asked to predict the number of repetitions they could complete before reaching MF on each exercise. Participants underpredicted the number of repetitions they could perform to MF (Standard error of measurements [95% confidence intervals] for combined sample ranged between 2.64 [2.36–2.99] and 3.38 [3.02–3.83]). There was a tendency towards improved accuracy with greater experience. Ability to predict repetitions to MF is not perfectly accurate among most trainees though may improve with experience. Thus, RIR should be used cautiously in prescription of RT. Trainers and trainees should be aware of this as it may have implications for the attainment of training goals, particularly muscular hypertrophy.

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

“…Hence, RIR scales might be more advantageous in these populations assuming they are able to accurately predict their repetition performance. Though, Hackett et al (2016) concluded that the ability to predict proximity to MF was not impacted by RT experience and Steele et al (2017a), though reporting improvement with experience, still found the most experienced were less than adequately accurate.…”

“…These RIR scales are designed as a way of assessing/controlling effort by participants estimating how many repetitions they can perform before reaching MF. RIR scales have been argued to be a more valid method of representing effort in close proximity to MF when compared to traditional RPE scales or the use of relative demands from a test of strength (i.e % of one repetition maximum [1RM]; Hackett et al, 2012;Helms et al, 2016;Steele, Endres, Fisher, Gentil & Giessing, 2017a). Indeed, traditional RPE scales often result in submaximal ratings even at MF (Steele, Fisher, McKinnon & McKinnon, 2017c).…”

“…Indeed, traditional RPE scales often result in submaximal ratings even at MF (Steele, Fisher, McKinnon & McKinnon, 2017c). Further, the numbers of possible repetitions prior to MF at the same relative loads (%1RM) vary between attempts and individuals (Steele, 2014;Steele et al, 2017a;Steele et al, 2017b). Thus, RIR scales might provide a more accurate way of controlling for effort during RT.…”

“…Steele and colleagues (2017a) for example examined the ability of participants with a range of prior RT experience to predict a priori how many repetitions they could perform to MF. They reported that participants under predicted with standard error of measurements (SEMs) between predicted and actual repetitions ranging from 2.36 to 3.83 (Steele et al, 2017a). Altoé Lemos et al (2017) examined participant's ability to predict repetitions to MF after they had performed an initial 2 repetitions of a set to MF across multiple sets with descriptive data suggesting that participants tended to under predict, though this improved with increased loads.…”

“…It thus seems that predictive 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 5 ability is less than accurate whether predictions are made a priori, or even at various points during the gestalt experience of performing a set of repetitions. The ability of predicting repetitions to MF might be better in experienced trainees and improve with training experience (Hackett et al, 2012;Helms et al, 2016;Steele et al, 2017a). Hence, RIR scales might be more advantageous in these populations assuming they are able to accurately predict their repetition performance.…”