Validation of equation based on repetitions to failure to adjust the training load in women undergoing resistance training

Validação de equação baseada em repetições até a falha para ajuste da carga de treinamento em mulheres submetidas ao treinamento de força

Abstract

Abstract  The objective of this study was to analyze the validation of the equation based on repetitions to failure for training load adjustment in middle-aged women undergoing resistance training (RT). Ten women (35.5 ± 5.0 years, 67.8 ± 11.6 kg, 165.9 ± 4.5 cm, 24.5 ± 3.8 m/kg2) with previous experience in RT of at least one year were selected to participate in this research. The participants performed two resistance exercise sessions, separated by intervals of at least 48 h. In the first session, the participants completed the maximum repetition test to determine the load for the following session. The equation based on repetitions to failure aimed to adjust the load for 8-12 RM load was applied. The second session was conducted with the load adjusted according to the equation, in which the participants performed three sets to failure. The eight exercises tested showed averages within the 8-12 RM repetition zone. Leg press 45^o = 11.3 (8.8-13.6), seated row = 11.3 (8.9-13.7), knee extension = 9.3 (8.5-10.0), bench press = 9, 2 (8.2-10.1), leg curl = 7.5 (6.5-8.4), lat pulldown = 8.6 (7.4-9.8), standing calf raise = 13.6 (11.3 -15.9), and triceps pushdown = 11.6 (9.8-13.3). Results suggest that the equation based on repetitions to failure is a valid strategy for adjusting the training load intensity in resistance exercises in women with previous experience in RT.

Key words:
Strength training; Predictive equations; Repetition maximum

Resumo

Resumo  O objetivo deste estudo foi analisar a validação da equação baseada em repetições até a falha para ajuste da carga de treinamento em mulheres de meia-idade submetidas ao Treinamento Resistido (TR). Dez mulheres (35,5 ± 5,0 anos, 67,8 ± 11,6 kg, 165,9 ± 4,5 cm, 24,5 ± 3,8 m/kg²), com experiência prévia em TR de pelo menos um ano, foram selecionadas para participar desta pesquisa. As participantes realizaram duas sessões de exercício resistido, separadas por intervalos de pelo menos 48 h. Na primeira sessão, as participantes realizaram o teste de repetições máximas para determinar a carga para a sessão seguinte. A equação baseada em repetições até a falha teve como objetivo ajustar a carga para carga de 8-12 RM. A segunda sessão foi conduzida com a carga ajustada de acordo com a equação, na qual as participantes realizaram três séries até a falha. Os oito exercícios testados apresentaram médias dentro da zona de repetições de 8-12 RM. Leg press 45° = 11,3 (8,8 - 13,6), remada sentada = 11,3 (8,9 - 13,7), extensão de joelhos = 9,3 (8,5 - 10,0), supino reto = 9,2 (8,2 - 10,1), flexão de pernas = 7,5 (6,5 - 8,4), puxada alta = 8,6 (7,4 - 9,8), elevação de panturrilhas em pé = 13,6 (11,3 - 15,9) e tríceps pushdown = 11,6 (9,8 - 13,3). Os resultados sugerem que a equação baseada em repetições até a falha é uma estratégia válida para ajustar a intensidade da carga de treinamento em exercícios resistidos em mulheres com experiência prévia em treinamento resistido.

Palavras-chave:
Treinamento de força; Equações preditivas; Repetições máximas

INTRODUCTION

Resistance training (RT) has been widely recommended due to the benefits of this type of physical exercise in promoting healthy morphological, functional, and metabolic adaptations, reducing the risk of developing diseases and premature death¹,². The benefits provided by RT depend on the appropriate manipulation of the variables that make up a training session, such as training intensity and volume, and the selection and organization of exercises².

Specifically, the intensity of the load is related to the amount of weight mobilized in an exercise. It can influence the metabolic³ and hemodynamic responses⁴, muscle protein synthesis⁵,⁶, motor units recruitment⁷, and psychophysiological responses, such as the perception of effort, pleasure/displeasure, and discomfort⁸,⁹. In addition to the acute effects, the intensity of the load is also associated with chronic adaptations, being the primary moderating variable of strength gains, in which there is a dose-response relationship between the intensity used and the increase in maximum strength⁹,¹⁰. Therefore, an adequate prescription of the training load is of fundamental importance to guarantee the necessary intensity to reach the planned goals.

The greatest load that can be lifted in a specific repetition zone is a method often applied to determine the intensity of load¹. This strategy is suitable from a practical point of view, as it has excellent ecological validity, precision, applicability, and effectiveness in promoting muscular adaptations¹. Of note, estimating repetitions to failure is a very useful strategy to find the desired load for the repetition zone. This approach of adjusting the load according to the number of repetitions performed has been used in some scientific experiments, making training load adjustment entirely objective¹¹-¹³ and, briefly, it represents a valid and accurate procedure to determine if changes on training load are necessary.

However, no experiment has verified this equation's validity in determining the load for a specific zone of repetitions. In addition, most experiments were conducted with young or older adults; therefore, there is a gap related to middle-aged individuals, especially women. Considering the scarcity of information oriented to the professional responsible for prescribing the RT program regarding the parameters used to determine the training load, the purpose of this study was to analyze the validation of the equation based on repetitions to failure for training load adjustment in middle-aged women undergoing RT.

METHODS

Experimental design

The participants made two visits to the laboratory, separated by 48 h. Anthropometric measurements and individual interviews were performed on the first visit. In addition, on the first visit, the participants performed the maximum repetition test to determine the load for the following session. On the second visit, the equation was validated, in which the participants performed three sets to failure with the load adjusted according to the equation in eight exercises. All sessions were conducted at the same time of the day to avoid possible confounding effects of the circadian cycle and to reduce possible climatic interference on the evaluation days.

Participants

A convenience sample of 10 women with at least one year of previous experience with RT was selected to participate in this research. All participants completed a detailed health history questionnaire, were free of orthopedic injuries that could prevent or hinder the exercise performed, and reported not being on hormone replacement therapy. All participants were informed about the research procedures and signed an informed consent form to participate in the study. The investigation was carried out according to the principles described in the Declaration of Helsinki and was approved by the Research Ethics Committee of the local university.

Anthropometry

Body mass was measured to the nearest 0.1 kg using a calibrated electronic scale (Balmak, Laboratory Equipment Labstore, Curitiba, PR, Brazil), with participants wearing light workout clothing and no shoes. Height was measured to the nearest 0.1 cm by a stadiometer attached to the scale with participants standing and no shoes. Body mass index (BMI) was calculated as body mass in kilograms divided by the square of height in meters.

Procedures

The 8-12 RM repetition zone was used as the reference standard for test validation. Therefore, the equation adjustment was applied to find the load corresponding to 8-12 RM. The order of the exercises performed in the two sessions was: 1) leg press 45º, 2) seated row, 3) knee extension, 4) bench press, 5) leg curl, 6) lat pulldown, 7) standing calf raise, and 8) triceps pushdown.

In the first experimental session, the participants performed three sets. In the first two sets, they performed eight repetitions, and in the third set, the participants performed as many repetitions as possible. Muscle failure for the third set was defined as the moment when the participant tried to perform the concentric action but could not complete the repetition or maintain proper technique during the repetition. In the second experimental session, the participants performed three sets per exercise until momentary concentric failure, with the load adjusted according to the following equation.

• Upper limb exercises: $FL=TL+ER/2$

• Lower limb exercises: $FL=TL+ER$

Where FL is the final load (kg) used in the experimental session (second session), TL is the load (kg) used in the test (first session), and ER is how many repetitions exceeded eight repetitions in the third set of the first session. Therefore, for upper limb exercises, 1 kg was added for every two repetitions that exceeded eight repetitions of the third set in the first session. For the lower limb exercises, 1 kg was added for each repetition that exceeded eight repetitions of the third set in the first session. Thus, the ratio between load increase and repetitions was 1:2 for upper limb exercises and 1:1 for lower limb exercises.

The procedures described above were repeated for the eight exercises that made up the RT sessions. The load used in the sets of the first session was based on previous information provided by the participants and the perception of the researchers. The rest interval between sets and exercises was two minutes in both experimental conditions. Participants were instructed to perform concentric and eccentric actions at one and two seconds, respectively. Figure 1 displays the experimental design adopted for this investigation.

Figure 1
Experimental design of the study.

Statistical analysis

Normality was checked by the Shapiro-Wilk’s test. The data were expressed as means, standard deviations, and 95% confidence intervals. The 8 and 12 repetitions values were adopted as standard reference parameters for comparison. The comparison between the total number of repetitions performed with the reference values was carried out using the 95% confidence interval; thus, it was possible to analyze when the repetitions performed were different from the reference values. The data were stored and analyzed using the statistical program SPSS version 21.0 (IBM Corp., Armonk, NY, USA).

RESULTS

Table 1 presents information regarding the general characteristics of the participants. The number of repetitions performed in each set according to the exercise is shown in Table 2. In the leg press 45^o, seated row, and standing calf raise exercises, the three sets had repetitions greater than eight repetitions; however, they were similar to 12 repetitions. For the knee extensor, bench press, knee flexor, and lat pulldown exercises, the three sets showed results similar to eight repetitions; however, less than 12 repetitions. In the triceps pushdown, the first two sets presented values greater than eight repetitions; however, similar to 12 repetitions, in the third set, an average of 10.5 repetitions was observed, and the 95% confidence interval was greater than eight and less than 12 repetitions.

Table 1
General characteristics of the participants (n = 10).

Variables	Mean	SD	95% CI
Age (years)	35.5	5.0	31.9 – 39.1
Body mass (kg)	67.8	11.6	59.4 – 76.1
Height (cm)	165.9	4.5	162.6 – 169.1
BMI (m/kg2)	24.5	3.8	21.8 – 27.3
Resistance training experience (months)	85.2	66.3	37.7 – 132.6

• Note: BMI = body mass index. Data are presented as mean, standard deviation (SD) and 95% confidence interval (95% CI).

Table 2
Maximum number of repetitions to failure in each set according to the exercise in women (n = 10).

Exercises	Sets	Mean	SD	95% CI
Leg press	1	12.1#	5.4	8.2 – 15.9
	2	10.6#	2.5	8.7 – 12.4
	3	11.0#	2.8	8.9 – 13.0
Seated row	1	11.8#	3.9	8.9 – 14.6
	2	11.4#	3.2	9.0 – 13.7
	3	10.8#	3.3	8.7 – 13.2
Knee extension	1	10.7*	1.5	9.5 – 11.8
	2	9.0*	1.0	8.2 – 9.7
	3	8.2*	1.3	7.2 – 9.1
Bench press	1	10.5*	1.5	9.3 – 11.6
	2	9.1*	1.5	8.0 – 10.1
	3	8.0*	2.0	6.5 – 9.4
Leg curl	1	7.9*	1.3	6.9 – 8.8
	2	7.5*	1.7	6.2 – 8.7
	3	7.1*	1.4	6.0 – 8.1
Lat pulldown	1	9.8*	2.4	8.0 – 11.5
	2	8.6*	1.7	7.3 – 9.8
	3	7.5*	1.9	6.4 – 8.8
Standing calf raise	1	13.8#	3.8	11.0 – 16.5
	2	13.5#	3.2	11.1 – 15.8
	3	13.7#	3.4	11.2 – 16.1
Triceps pushdown	1	12.5#	3.9	9.6 – 15.3
	2	11.9 #	3.4	9.4 – 14.3
	3	10.5*#	1.2	9.5 – 11.4

• Note: *difference from 12 repetitions. ^#difference from 8 repetitions. Data presented as mean, standard deviation (SD) and 95% confidence interval (95% CI).

Figure 2 shows the average of repetitions performed in the three sets according to the exercise. The leg press 45^o, seated row, standing calf raise, and triceps pushdown exercises presented a 95% IC that indicated similarity with 12 repetitions; however, superior to eight repetitions. In turn, knee flexion and lat pulldown exercises showed results of less than 12 repetitions, however, similar to eight repetitions. In the knee extensor and bench press exercises, the average was between eight and 12 repetitions, not crossing the confidence intervals for 12 and eight repetitions.

Figure 2
Average repetitions of three sets according to the exercise in middle-aged women (n = 10). Data presented as mean and 95% confidence interval.

DISCUSSION

The objective of this study was to verify whether the equation based on repetitions to failure is a valid tool for adjusting the training load intensity for the 8-12 RM in women practicing resistance training. The main finding was that the equation could adjust the load to the 8-12 RM zone.

Training intensity, specifically based on the load applied to the exercises, is one of the most important RT variables to promote muscular adaptations¹. Generally, specific zones of repetitions can express the load intensity; thus, finding a load that leads the practitioner to a specific number of repetitions is needed. Our results indicate that the equation based on repetition to failure is a valid alternative for training load adjustment to the 8-12 RM zone since, in all sets of all exercises, the repetitions did not differ from 8 RM or 12RM.

The repetition zone of 8-12 RM was chosen as a comparison parameter since this zone is suggested to promote muscle hypertrophy¹. In addition, this specific repetition zone may also promote an increase in maximum strength and localized muscular endurance¹⁴. Still, it is a repetition zone that promotes better sensations of pleasure and less discomfort than other intensities¹²,¹⁵.

The equation applicability suggests that the load needed to increase at a ratio between repetition exceeded and load of 1:2 for upper limb exercises and 1:1 for lower limb exercises. This means that it is necessary to perform two repetitions above eight repetitions to add 1 kg in the upper limb exercises, while for the lower limb exercises, the load is added by 1 kg for each repetition exceeding eight repetitions. The American College of Sports Medicine, in its position on the prescription and progression of RT, suggests that load progression should occur in greater magnitude for the lower limbs compared to the upper limbs¹. Therefore, increasing the absolute load in the upper limbs is more difficult than in the lower limbs.

Another performance-based method to adjust the training load for a specific number of repetitions was proposed by Mann et al.¹⁶, which consists of adapting the load based on the number of repetitions performed in the last two sets of a given exercise. In the proposed model, participants perform four sets per exercise, the first set with 50% of the load for 6RM, the second set with 75% of the load for 6RM, and the third set with 100% of the load for 6RM. The repetitions are performed until muscle failure in the third set. Then, the load for the fourth set is adjusted based on the number of repetitions achieved during the third set, and the fourth set is also performed until muscle failure and, according to the number of repetitions performed in the fourth set, the load will be adjusted for the next session.

A traditional method for adjusting training intensity is based on the percentage of maximum strength obtained through the 1RM test¹. However, although the 1RM test has wide acceptance in the scientific community, a wide range of studies have observed that to obtain a reliable measurement, more than a single session of evaluations would be necessary to guarantee load stabilization¹⁷-¹⁹. Furthermore, load stabilization in the 1RM test depends on the type of exercise involved¹⁸. In addition, the number of repetitions performed at the same percentage of maximum strength, based on 1RM estimates, may differ among exercises¹⁹, between men and women¹⁴, and among individuals with different levels of training²⁰. Regarding the effectiveness of load intensity prescription methods on muscle adaptations, Nóbrega et al.²¹ reported that the repetition zone is superior in promoting hypertrophy than the percentage of 1RM and similar for strength increase. Considering all these factors, the prescription of load by percentages of 1RM is limited in the practical field.

Scales to determine the rate of perceived effort (RPE) are also used to determine the training load, mainly because it is a low-cost method with easy applicability²². However, it may present great heterogeneity among participants²³, therefore being more susceptible to variability. Since RPE is a translation of internal load into representative scores, this report can be affected by factors that vary from individual to individual, such as training level and psychological and genetic factors, resulting in distinct experiences during exercise when exposed to the same external load. In addition, the RPE scale presents limitations in identifying the point of maximum effort since many studies have observed that RPE values are not always maximally reported, even when the maximum number of repetitions is performed⁹,²⁴.

In this sense, the repetition in reserve is also a suggested tool to measure how far the muscle failure point is. This approach aims to determine how many repetitions the individual could perform beyond those achieved. Therefore, this may help to determine how much weight will be increased. However, the prediction error is greater with lighter loads, and the amount of sets²⁵ is dependent on the level of training²⁶ and the type of exercise²⁷.

Studies indicate that it is unnecessary to perform sets to muscular failure to maximize muscle hypertrophy and strength gains²⁸,²⁹, and training near muscle failure (approximately 2-3 repetitions in reserve) will be enough to optimize muscular adaptations³⁰. However, our findings indicate that performing the final set until muscle failure is an interesting strategy to adjust the training load and verify the moment of load progression. Meantime, future studies should address the timing of testing application to adjust training load.

Our study has some limitations, such as the small number of participants. Furthermore, the results are specific to the exercises, session configuration, and population studied. Therefore, caution must be taken in extrapolating the results to different training session configurations and populations. As strong points of our study, we highlight the employment of a typical RT training program; the sample was composed of women with previous experience in RT, so they probably performed the exercises at an optimal technique, which altogether reinforces the ecological validity of this research.

CONCLUSION

Results suggest that the equation based on repetitions to failure is a valid strategy for adjusting the training load intensity in RT program. From a practical point of view, the equation presents a viable strategy due to its validity, low financial cost, easy application, and versatility concerning exercises since it can be applied in practically all resistance exercises.

Data Availability Statement

Research data is only available upon request.

How to cite this article

Ainhagne M, Martinho DV, Nascimento MA, Salles BF, Oliveira MR, Santos L, Ribeiro AS. Validation of equation based on repetitions to failure to adjust the training load in women undergoing resistance training. Rev Bras Cineantropom Desempenho Hum 2025, 27:e99657. DOI: https://doi.org/10.1590/1980-0037.2025v27e99657

COMPLIANCE WITH ETHICAL STANDARDS

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. This study was funded by the authors. L.S. is supported by National Council of Technological and Scientific Development (CNPq/Brazil) with a postdoctoral fellowship (CNPq process: 152781/2024-2).

Ethical approval

Ethical approval was obtained from the local Human Research Ethics Committee – 99306718.1.0000.0108 and the protocol (no. 3.145.335) was written in accordance with the standards set by the Declaration of Helsinki.

REFERENCES

• ¹ American College of Sports Medicine. Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2009;41(3):687-708. http://doi.org/10.1249/MSS.0b013e3181915670 PMid:19204579.
  » http://doi.org/10.1249/MSS.0b013e3181915670
• ² Fragala MS, Cadore EL, Dorgo S, Izquierdo M, Kraemer WJ, Peterson MD, et al. Resistance training for older adults: position statement from the national strength and conditioning association. J Strength Cond Res. 2019;33(8):2019-52. http://doi.org/10.1519/JSC.0000000000003230 PMid:31343601.
  » http://doi.org/10.1519/JSC.0000000000003230
• ³ Gjovaag T, Hjelmeland AK, Oygard JB, Vikne H, Mirtaheri P. Acute hemodynamic and cardiovascular responses following resistance exercise to voluntary exhaustion: effects of different loadings and exercise durations. J Sports Med Phys Fitness. 2016;56(5):616-23. PMid:27285350.
• ⁴ Gjøvaag TF, Mirtaheri P, Simon K, Berdal G, Tuchel I, Westlie T, et al. Hemodynamic responses to resistance exercise in patients with coronary artery disease. Med Sci Sports Exerc. 2016;48(4):581-8. http://doi.org/10.1249/MSS.0000000000000811 PMid:26559450.
  » http://doi.org/10.1249/MSS.0000000000000811
• ⁵ Kumar V, Selby A, Rankin D, Patel R, Atherton P, Hildebrandt W, et al. Age-related differences in the dose-response relationship of muscle protein synthesis to resistance exercise in young and old men. J Physiol. 2009;587(1):211-7. http://doi.org/10.1113/jphysiol.2008.164483 PMid:19001042.
  » http://doi.org/10.1113/jphysiol.2008.164483
• ⁶ Burd NA, West DWD, Staples AW, Atherton PJ, Baker JM, Moore DR, et al. Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men. PLoS One. 2010;5(8):e12033. http://doi.org/10.1371/journal.pone.0012033 PMid:20711498.
  » http://doi.org/10.1371/journal.pone.0012033
• ⁷ Schoenfeld BJ, Contreras B, Willardson JM, Fontana F, Tiryaki-Sonmez G. Muscle activation during low- versus high-load resistance training in well-trained men. Eur J Appl Physiol. 2014;114(12):2491-7. http://doi.org/10.1007/s00421-014-2976-9 PMid:25113097.
  » http://doi.org/10.1007/s00421-014-2976-9
• ⁸ Elsangedy HM, Machado DGDS, Krinski K, Nascimento PHD, Oliveira GTA, Santos TM, et al. Let the pleasure guide your resistance training intensity. Med Sci Sports Exerc. 2018;50(7):1472-9. http://doi.org/10.1249/MSS.0000000000001573 PMid:29432325.
  » http://doi.org/10.1249/MSS.0000000000001573
• ⁹ Pritchett RC, Green JM, Wickwire PJ, Kovacs M. Acute and session RPE responses during resistance training: bouts to failure at 60% and 90% of 1RM. S Afr J Sports Med. 2009;21(1):23-6. http://doi.org/10.17159/2078-516X/2009/v21i1a304
  » http://doi.org/10.17159/2078-516X/2009/v21i1a304
• ¹⁰ Lopez P, Radaelli R, Taaffe DR, Newton RU, Galvão DA, Trajano GS, et al. Resistance training load effects on muscle hypertrophy and strength gain: systematic review and network meta-analysis. Med Sci Sports Exerc. 2021;53(6):1206-16. http://doi.org/10.1249/MSS.0000000000002585 PMid:33433148.
  » http://doi.org/10.1249/MSS.0000000000002585
• ¹¹ Ribeiro AS, Santos ED, Nunes JP, Schoenfeld BJ. Acute effects of different training loads on affective responses in resistance-trained men. Int J Sports Med. 2019;40(13):850-5. http://doi.org/10.1055/a-0997-6680 PMid:31499564.
  » http://doi.org/10.1055/a-0997-6680
• ¹² Pereira LC, Nunes JP, Kassiano W, Aguiar AF, Ribeiro AS. Acute effect of different resistance training loads on perceived effort and affectivity in older women: a cross-over and randomized study. Aging Clin Exp Res. 2022;34(6):1333-9. http://doi.org/10.1007/s40520-021-02062-z PMid:35023050.
  » http://doi.org/10.1007/s40520-021-02062-z
• ¹³ Ribeiro AS, Avelar A, Schoenfeld BJ, Fleck SJ, Souza MF, Padilha CS, et al. Analysis of the training load during a hypertrophy-type resistance training programme in men and women. Eur J Sport Sci. 2015;15(4):256-64. http://doi.org/10.1080/17461391.2014.940559 PMid:25068761.
  » http://doi.org/10.1080/17461391.2014.940559
• ¹⁴ Ribeiro AS, Avelar A, Schoenfeld BJ, Trindade MCC, Ritti-Dias RM, Altimari LR, et al. Effect of 16 weeks of resistance training on fatigue resistance in men and women. J Hum Kinet. 2014;42(1):165-74. http://doi.org/10.2478/hukin-2014-0071 PMid:25414750.
  » http://doi.org/10.2478/hukin-2014-0071
• ¹⁵ Shimano T, Kraemer WJ, Spiering BA, Volek JS, Hatfield DL, Silvestre R, et al. Relationship between the number of repetitions and selected percentages of one repetition maximum in free weight exercises in trained and untrained men. J Strength Cond Res. 2006;20(4):819-23. PMid:17194239.
• ¹⁶ Mann JB, Thyfault JP, Ivey PA, Sayers SP. The effect of autoregulatory progressive resistance exercise vs. linear periodization on strength improvement in college athletes. J Strength Cond Res. 2010;24(7):1718-23. http://doi.org/10.1519/JSC.0b013e3181def4a6 PMid:20543732.
  » http://doi.org/10.1519/JSC.0b013e3181def4a6
• ¹⁷ Ribeiro AS, do Nascimento MA, Mayhew JL, Ritti-Dias RM, Avelar A, Okano AH, et al. Reliability of 1RM test in detrained men with previous resistance training experience. Isokinet Exerc Sci. 2014;22(2):137-43. http://doi.org/10.3233/IES-130530
  » http://doi.org/10.3233/IES-130530
• ¹⁸ Ribeiro AS, Nascimento MA, Salvador EP, Gurjão ALD, Avelar A, Ritti-Dias RM, et al. Reliability of one-repetition maximum test in untrained young adult men and women. Isokinet Exerc Sci. 2014;22(3):175-82. http://doi.org/10.3233/IES-140534
  » http://doi.org/10.3233/IES-140534
• ¹⁹ Nascimento MA, Ribeiro AS, Souza Padilha C, Silva DRP, Mayhew JL, Campos MGA Fo, et al. Reliability and smallest worthwhile difference in 1RM tests according to previous resistance training experience in young women. Biol Sport. 2017;3(3):279-85. http://doi.org/10.5114/biolsport.2017.67854
  » http://doi.org/10.5114/biolsport.2017.67854
• ²⁰ Ribeiro AS, Avelar A, Nascimento MA, Mayhew JL, Campos MGA Fo, Eches EHP, et al. What is the actual relative intensity of a resistance training program for men and women? Isokinet Exerc Sci. 2014;22(3):217-24. http://doi.org/10.3233/IES-140542
  » http://doi.org/10.3233/IES-140542
• ²¹ Nóbrega SR, Scarpelli MC, Barcelos C, Chaves TS, Libardi CA. Muscle hypertrophy is affected by volume load progression models. J Strength Cond Res. 2023;37(1):62-7. http://doi.org/10.1519/JSC.0000000000004225 PMid:36515591.
  » http://doi.org/10.1519/JSC.0000000000004225
• ²² Scott BR, Duthie GM, Thornton HR, Dascombe BJ. Training monitoring for resistance exercise: theory and applications. Sports Med. 2016;46(5):687-98. http://doi.org/10.1007/s40279-015-0454-0 PMid:26780346.
  » http://doi.org/10.1007/s40279-015-0454-0
• ²³ Gomes RL, Lixandrão ME, Ugrinowitsch C, Moreira A, Tricoli V, Roschel H. Session rating of perceived exertion as an efficient tool for individualized resistance training progression. J Strength Cond Res. 2022;36(4):971-6. http://doi.org/10.1519/JSC.0000000000003568 PMid:32304519.
  » http://doi.org/10.1519/JSC.0000000000003568
• ²⁴ Helms ER, Cronin J, Storey A, Zourdos MC. Application of the repetitions in reserve-based rating of perceived exertion scale for resistance training. Strength Condit J. 2016;38(4):42-9. http://doi.org/10.1519/SSC.0000000000000218 PMid:27531969.
  » http://doi.org/10.1519/SSC.0000000000000218
• ²⁵ Halperin I, Malleron T, Har-Nir I, Androulakis-Korakakis P, Wolf M, Fisher J, et al. Accuracy in predicting repetitions to task failure in resistance exercise: a scoping review and exploratory meta-analysis. Sports Med. 2022;52(2):377-90. http://doi.org/10.1007/s40279-021-01559-x PMid:34542869.
  » http://doi.org/10.1007/s40279-021-01559-x
• ²⁶ Zourdos MC, Klemp A, Dolan C, Quiles JM, Schau KA, Jo E, et al. Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. J Strength Cond Res. 2016;30(1):267-75. http://doi.org/10.1519/JSC.0000000000001049 PMid:26049792.
  » http://doi.org/10.1519/JSC.0000000000001049
• ²⁷ Hackett DA, Cobley SP, Davies TB, Michael SW, Halaki M. Accuracy in estimating repetitions to failure during resistance exercise. J Strength Cond Res. 2017;31(8):2162-8. http://doi.org/10.1519/JSC.0000000000001683 PMid:27787474.
  » http://doi.org/10.1519/JSC.0000000000001683
• ²⁸ Grgic J, Schoenfeld BJ, Orazem J, Sabol F. Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: a systematic review and meta-analysis. J Sport Health Sci. 2022;11(2):202-11. http://doi.org/10.1016/j.jshs.2021.01.007 PMid:33497853.
  » http://doi.org/10.1016/j.jshs.2021.01.007
• ²⁹ Vieira AF, Umpierre D, Teodoro JL, Lisboa SC, Baroni BM, Izquierdo M, et al. Effects of resistance training performed to failure or not to failure on muscle strength, hypertrophy, and power output: a systematic review with meta-analysis. J Strength Cond Res. 2021;35(4):1165-75. http://doi.org/10.1519/JSC.0000000000003936 PMid:33555822.
  » http://doi.org/10.1519/JSC.0000000000003936
• ³⁰ Refalo MC, Helms ER, Trexler ET, Hamilton DL, Fyfe JJ. Influence of resistance training proximity-to-failure on skeletal muscle hypertrophy: a systematic review with meta-analysis. Sports Med. 2023;53(3):649-65. http://doi.org/10.1007/s40279-022-01784-y PMid:36334240.
  » http://doi.org/10.1007/s40279-022-01784-y

Corresponding author

Leandro dos Santos. State University of Londrina – UEL Rua Agostinho Feijó Sanches, 155, 86079-429, Santa Mônica, Londrina (PR), Brasil. E-mail: [e-mail]

Scientific Editor:

Diego Augusto Santos Silva

Conflict of interest statement

The authors have no conflict of interests to declare.

Publication Dates

• Publication in this collection
  16 June 2025
• Date of issue
  2025

History

• Received
  16 July 2024
• Accepted
  03 Apr 2025