(14) INTER-SESSION ACCURACY OF REPETITIONS-IN-RESERVE DURING THE BENCH PRESS AND BACK SQUAT IN FIREFIGHTER CADETS

Purpose: An emerging tool to help regulate load during resistance training is repetitions-in reserve (RIR) (1). RIR allows an individual to adjust their starting load based on number of repetitions they feel they could have performed before muscular failure, and then during subsequent sets perform only the number of repetitions until they hit this RIR target (e.g., 2 RIR). RIR has potential applications in the fire service, where the workload of a shift necessitates flexible load in exercise programming. While studies have investigated the accuracy of RIR for load-selection (2) and during sets of fixed repetitions (3), the repeatability of RIR between sessions under high load conditions in upper and lower extremity exercises remains unknown. The purpose of this study was to examine inter-session differences in RIR accuracy during the bench press and back squat exercises under high load conditions in FF cadets.Methods: 13 FF cadets (12 male, 1 female; 18.98 ± 0.54 yrs, 1.80 ± 11.04 m, 85.07 ± 21.69 kg) with mixed resistance training experience were enrolled from the same Midwestern fire training academy. Participants were randomly assigned to either the bench press or back squat group and completed three separate sessions, separated by 72 hours for recovery. The initial session included anthropometric measures, RIR instruction and familiarization, and concluded with 1RM testing using a submaximal approach (4) with integrated RIR estimation practice. Testing sessions 1 and 2 each included a warm-up set of 15 repetitions using 30% 1RM. After a 3-minute rest, the participants performed a testing set at 85% 1RM and were instructed to verbalize when they felt they had reached 2 RIR but were instructed to continue until failure. For testing sessions 1 and 2, an accuracy score (RIR_diff) was calculated by subtracting the sum of the repetitions at the point of verbalizing RIR plus the RIR target (i.e., 2 RIR) from the total repetitions performed. A repeated measures ANOVA determined significant differences in RIR_diff between the bench press and back squat. An alpha of 0.05 determined statistical significance.Results: There were no differences in RIR_diff within subjects across testing sessions (F = 0.28, p = 0.605) or between exercise groups (F = 0.66, p = 0.433). Further, 85% and 77% of participants scored within 2 repetitions of 2 RIR during testing session 1 and 2, respectively (Figure 1).Conclusions: Under high load conditions, the FF cadets are consistent in their ability to predict 2 RIR, regardless of upper or lower body exercise. This also suggests that a single familiarization session may have carryover into future sessions.Practical Applications: Implementing RIR into programming for FF cadets may be effective in regulating overall training load, though the familiarization process may benefit from including a set of exercise to failure. Future research should investigate accuracy when using various RIR targets under both high and low loads.Acknowledgements: None

References:
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