No abstract

Hackett, DA, Cobley, SP, Davies, TB, Michael, SW, and Halaki, M. Accuracy in estimating repetitions to failure during resistance exercise. J Strength Cond Res 31(8): 2162-2168, 2017-The primary aim of this study was to assess the accuracy in estimation of repetitions to failure (ERF) during resistance exercise. Furthermore, this investigation examined whether the accuracy in ERF was affected by training status, sex, or exercise type. Eighty-one adults (men, n = 53 and women, n = 28) with broad range of resistance training experience participated in this study. Subjects performed up to 10 sets of 10 repetitions at 70% 1 repetition maximum (1RM) and 80% 1RM for the chest press and leg press, respectively. At the completion of each set, subjects reported their ERF and then continued repetitions to failure to determine actual repetitions to failure (ARF). The accuracy (amount of error) of ERF was determined over an ARF 0-10. Significant differences were found for error of ERF among ARF (p < 0.001), with the error of ERF ∼1 repetition at ARF 0-5 compared with >2 repetitions at ARF 7-10. Greater accuracy was found for the chest press compared with leg press, with the error of ERF ≤1 repetition for ARF 0-5 and ARF 0-3, respectively (p = 0.012). Men were found to be more accurate than women at specific ARFs for the leg press (p = 0.008), whereas no interaction was found for the chest press. Resistance training experience did not affect the accuracy in ERF. These results suggest that resistance trainers can accurately estimate repetitions to failure when close to failure and that ERF could importantly be practically used for prescription and monitoring of resistance exercise.

In this study, we examined the validity of a novel subjective scale for assessing resistance-exercise effort. Seventeen male bodybuilders performed five sets of 10 repetitions at 70% of one-repetition maximum, for the bench press and squat. At the completion of each set, participants quantified their effort via the rating of perceived exertion (RPE) and novel estimated-repetitions-to-failure scales, and continued repetitions to volitional exhaustion to determine actual-repetitions-to-failure. There were high correlations between estimated- and actual-repetitions-to-failure across sets for the bench press and squat (r ≥ 0.93; P < 0.05). During sets 3, 4, and 5, estimated-repetitions-to-failure predicted the number of repetitions to failure for the bench press and squat, as indicated by smaller effect sizes for differences (ES = 0.37-0.0). The estimated-repetitions-to-failure scale was reliable as indicated by high intraclass correlation coefficients (≥0.92) and narrow 95% limits of agreement (≤0.63 repetitions) for both the bench press and squat. Despite high correlations between RPE and actual-repetitions-to-failure (P < 0.05), RPE at volitional fatigue was less than maximal for both exercises. Our results suggest that the estimated-repetitions-to-failure scale is valid for predicting onset of muscular failure, and can be used for the assessment and prescription of resistance exercise.

We conclude that the questionnaires were successfully translated and show acceptable measurement properties, and, as such, are suitable for use in clinical and research applications.

Overall, the results suggest that despite statistically significant effects on muscular strength being found for non-failure compared with failure training, the small percentage of improvement shown for non-failure training is unlikely to be meaningful. Therefore, it appears that similar increases in muscular strength can be achieved with failure and non-failure training. Furthermore, it seems unnecessary to perform failure training to maximise muscular strength; however, if incorporated into a programme, training to failure should be performed sparingly to limit the risks of injuries and overtraining.

No abstract

This review and the results of the meta-analysis have demonstrated that positional groups have varied kinematic and metabolic demands. During match play, forwards sustain the greatest number of collisions and RHIE bouts, outside backs participate in more high-speed running and cover the greatest distance, and adjustables work at high intensity covering the greatest relative distance with the highest metabolic cost. Therefore, specific training for each positional group should address their match requirements. In addition, sub-elite players exhibit lower intensity of play compared with elite players, as indicated by lower relative distance and less number of efforts per RHIE bout despite similarities in total distance covered and number of RHIE bouts. To prepare them for elite-level play, their training should incorporate higher intensity drills in which greater relative distance and number of efforts per RHIE bout are performed. Furthermore, the lack of consistency in the definition of speed zones, high-intensity movement, collisions and impacts, underscores the difficulties encountered in meaningful comparisons of player activity profiles between studies. Consensus of these definitions would facilitate direct comparisons within rugby league.

Overall, the results suggest that fast and moderate-slow resistance training improve dynamic muscular strength similarly in individuals within a wide range of training statuses and ages. Resistance training performed at fast movement velocities using moderate intensities showed a trend for superior muscular strength gains as compared to moderate-slow resistance training. Both training practices should be considered for novice to advanced, young and older resistance trainers targeting dynamic muscular strength.