Journal of Exercise Physiologyonline

91 Journal of Exercise Physiologyonline June 2015 Volume 18 Number 3 Editor-in-Chief Official Research Journal of Tommy the American Boone, PhD, Society MBA of Review Exercise Board Physiologists Todd Astorino, PhD Julien Baker, ISSN 1097-9751 PhD Steve Brock, PhD Lance Dalleck, PhD Eric Goulet, PhD Robert Gotshall, PhD Alexander Hutchison, PhD M. Knight-Maloney, PhD Len Kravitz, PhD James Laskin, PhD Yit Aun Lim, PhD Lonnie Lowery, PhD Derek Marks, PhD Cristine Mermier, PhD Robert Robergs, PhD Chantal Vella, PhD Dale Wagner, PhD Frank Wyatt, PhD Ben Zhou, PhD Official Research Journal of the American Society of Exercise Physiologists ISSN 1097-9751 JEPonline Multi-Joint and Single-Joint Exercise Performance and Perceived Exertion with Several Different Recoveries Gilmar Senna 1,2, Estevão Scudese 2,3, Felipe Carneiro 2, Juliana Torres 2, Cristiano Queiroz 4, Estélio Dantas 1,2 1 Nursing and Biosciences Post-Graduation Program, Doctorate of Federal University of State of Rio de Janeiro, Brazil, 2 Biosciences Laboratory of Human Movement, Tiradentes University, Brazil, 3 School of Physical Education and Sports, Federal University of Rio de Janeiro, Brazil, 4 Health Center Science, Catholic of Petrópolis University, Brazil ABSTRACT Senna G, Scudese E, Carneiro F, Torres J, Queiroz C, Dantas E. Multi-Joint and Single-Joint Exercise Performance and Perceived Exertion with Several Different Recoveries. JEPonline 2015;18(3):91-100. The purpose of this study was to compare repetition performance and rate of perceived exertion (RPE) with different rest periods for multi-joint and single-joint exercises. Fourteen trained men (20.93 ± 2.40 yrs; 75.23 ± 9.37 kg; 176.64 ± 7.53 cm; 24.03 ± 1.62 kg m -2 ) completed 8 sessions with 3 sets of 10 RM loads. Barbell bench press (BP) or machine chest fly (MCF) were alternated (one each day) with different rest periods for each day (1-min, 2-min, 3-min, or 5-min). The results indicated that the shorter rest length presented greater reductions in repetition number for the BP (1-min < 2-min < 3-min, P 0.0001), but no differences were observed between the 3-min and the 5-min rest conditions. For MCF, significant differences were evidenced for rest periods of 1-min, 2-min, and 3-min compared to 5 -(P 0.0001). No significant differences were found between 1-min, 2-min, and 3- min. Both exercises presented progressive declines in repetition performance over consecutive sets. Increases in RPE were evident over the course of the consecutive sets for both exercises, with significant exertion values at the lower smaller rest conditions. In conclusion, the findings indicate that both exercises presented similar patterns in repetition performance and RPE. Key Words: Muscle Strength, Weight Lifting, Physical Fitness

92 INTRODUCTION According to the American College of Sports Medicine (1), the rest interval between sets can influence the outcome of resistance training programs. The most recent position statement (1), indicates that when emphasis is placed on strength development, power or hypertrophy, a 2-min to 3-min rest period is recommended for multi-joint exercises and recoveries of 1-min to 2-min between sets seems to be sufficient for single-joint exercises. Recently, several experiments have demonstrated that different rest lengths could promote distinct repetition performance for multiple sets of multi-joint exercises or over the course of a training session (7,11-15,17-19). However, after a rigorous search, the authors found few studies that verified the influence of rest interval length between sets for multi-joint and single-joint exercises (14,15). Of these studies, the authors have observed similar patterns over the reduction of repetition number in multi-joint and single-joint exercises, regardless of the rest length investigated. Additionally, Senna et al. (15) observed lower elevations in blood lactate concentrations caused by long intervals between sets for single-joint exercise. Further, the perceived exertion (RPE) values were significantly increased over successive sets for both the multi-joint and single-joint exercises with significantly greater values for the 1-min rest condition (14,15). However, given the current recommendations, there is little credible evidence regarding the 2-min rest length window especially for multi-joint and single-joint exercises in regards to repetition performance (14,15). This specific length (2-min) appears to be fundamental effort to consolidate the current rest recommendation (1). In addition to the importance of adding to the current body of knowledge for future recommendations, the purpose of this study was to compare the repetition performance and RPE with 1-min, 2-min, 3-min, and 5-min rest intervals between sets for multijoint and single-joint exercises. We hypothesized that multi-joint and single-joint exercises would reveal a similar pattern of repetitions performance output and RPE values. METHODS Subjects Fourteen trained men (20.93 ± 2.40 yrs; 75.23 ± 9.37 kg; 176.64 ± 7.53 cm; 24.03 ± 1.62 kg m -2 ; relative strength in BP: 1.57 ± 0.30 kg kg -1 body mass) participated in the study. All subjects indicated that they had 1-yr experience in resistance training with a minimum of 3 times wk -1 frequency. Also, each subject confirmed the absence of any medical condition that could influence the training program. None was using anabolic-androgenic steroids, ergogenic substances or drugs that could influence the subject s exercise performance. In addition, the subjects were instructed to avoid regular physical activity during the study period. Before data collection, all subjects responded negatively to the PAR-Q (16). The experimental procedure was approved by the Ethics Committee of the Federal University of Rio de Janeiro. Anthropometric variables and body composition were taken to determine the subjects height (cm) and weight (kg) for calculation of body mass index (BMI-weight/stature²), using a digital scale, Filizola, model PL 180 (Brazil) with accuracy of 0.01 kg and a stadiometer accurate to 0.1 cm, Sanny, model ES 2020 (Brazil). All procedures followed the recommendations of the International Society for the Advancement of Kinanthropometry (6). Ten Repetition Maximum After two familiarization sessions (similar to the test procedures), the 10 RM load was assessed for all subjects over four non-consecutive days with a randomized design. At the first-day, the subjects performed the 10 RM test for the bench press exercise (BP). During the second visit, the subjects

performed the 10 RM test on the machine chest fly (MCF). Two addition visits with similar procedures were necessary to determine the reproducibility of the 10 RM. For all testing sessions, each subject performed a maximum of three attempts for each exercise with 10 RM loads and 5 min of rest between attempts. The greatest load successfully lifted between the two testing visits was considered as the 10 RM value. Standard techniques were used for each exercise (2). To minimize errors in data collection, the following conditions were followed: (a) standardized instructions concerning testing procedures were given to the subjects; (b) all subjects were properly instructed on the techniques for each exercise; (c) body position was held constant; (d) verbal encouragement was provided during all testing procedures; and (e) mass of all free weights and barbell were determined using a precision scale. Experimental Procedures Seventy-two hrs after the last 10 RM test, the subjects completed the first of eight different experimental sessions (2 sessions wk -1 ). For each visit, 3 sets with 10 RM loads were performed on a random cross-over design in order to determine the exercise (BP or MCF) in combination with a given rest length (1-min, 2-min, 3-min, or 5-min) implemented for each experimental session. The warm-up before each exercise consisted of 2 sets of 12 repetitions with 40% of 10 RM loads. A recovery time of 3-min was allowed between the warm-up and the experimental procedure. The subjects were verbally encouraged to perform 3 sets until volitional exhaustion. No attempt was made to control the repetition velocity, however, the subjects were told to use a smooth, controlled movement. All visits were conducted at the same time of day in order to avoid any circadian accumulation effects. The number of repetitions and the RPE (verified by Omni Res Scale) were recorded to each set for purposes of later interpretation (4,5). Statistical Analysis The number of repetitions was presented by mean ± standard deviation (SD) and by the median for Omni Res Scale (RPE). An intra-class correlation coefficient was used for verify the load reproducibility between 10 RM tests and retest sessions. The ANOVA (one-way) for repeated measures was used to analyze repetitions performance data between sets and between different rest conditions for each exercise. When necessary, a Bonferroni post-hoc test was applied for pairwise comparisons. Additionally, to determine the magnitude of the findings, Effect Sizes (ESs) were calculated for each exercise set of each rest condition. The thresholds proposed by Cohen (3) were applied to determine the magnitude of the treatment effects. The Friedman test was used to detect differences in relation to RPE between sets and rest intervals conditions. When necessary, a Dunn post-hoc was implemented for pair-wise comparisons. The level of significance was set at P<0.05. Statistical software 10.0 version was used for statistical analyze (Statsoft, Inc, Tulsa, OK, USA). RESULTS Excellent reproducibility for 10 RM loads was observed between test and retest in both exercises (BP, r = 0.97; MCF, r = 0.94; P<0.0001). For BP, 1-min rest protocol resulted in significant reductions for the total number of repetitions compared with the other rest conditions (2-min, 3- min, and 5-min; P<0.002). Similarly, the 2-min protocol showed important decreases in total repetition number when compared with the longer 3-min and 5-min rest intervals (P<0.0001). However, no differences were identified between the 3-min and the 5-min rest conditions. For MCF, 1-min, 2-min, and 3-min of rest triggered significant reductions at the total number of repetitions compared to the longer 5-min rest condition (P<0.0001). Repetitions values per set and the total number of repetitions for both exercises for each rest protocol are presented in Table 1. 93

Figures 1 and 2 represent the curve pattern of reductions in the number of repetitions of each set different conditions in the interval exercises multi-joint and single-joint exercises, respectively. Table 1. Number of Repetition in Each Set and the Total Number of Repetitions with 1-Min, 2-Min, 3-Min, and 5-Min Rest Intervals. Data are means ± standard deviation. 94 Exercise and Rest Conditions Set 1 Set 2 Set 3 Total Number of Repetitions Bench Press 1-min 10.07 ± 0.26 7.00 ± 1.11* 5.21 ± 1.12* 22.28 ± 1.12# 2-min 10.71 ± 1.13 8.07 ± 1.14* 6.43 ± 1.22* 25.21 ± 2.86 3-min 10.21 ± 0.57 9.36 ± 0.93 8.07 ± 0.92* 27.64 ± 1.86 5-min 10.14 ± 0.36 9.42 ± 0.75 8.50 ± 0.65* 28.07 ± 1.31 Machine Chest Fly 1-min 10.57 ± 0.93 7.35 ± 1.01* 5.86 ± 0.66 * 23.78 ± 1.25 2-min 10.28 ± 0.61 8.35 ± 1.27* 6.35 ± 1.39* 25.00 ± 2.85 3-min 10.21 ± 0.69 8.35 ± 1.08* 7.21 ± 1.05* 25.78 ± 2.45 5-min 10.50 ± 0.65 9.85 ± 0.66 9.50 ± 1.09* 29.85 ± 1.95 Values are Expressed in Repetition maximum (RM). *Significant difference compared with set 1; Significant difference compared with set 2; #Significant difference compared with 2-min; Significant difference compared with 3-min; Significant difference compared with 5-min. Figure 1. Number of Repetitions in Each Set with Rest Intervals for Bench Press of 1-Min, 2- Min, 3-Min, and 5-Min. *Significant difference compared with Set 1; Significant difference compared with Set 2; #Significant difference compared with 2-min (P<0.05); Significant difference compared with 3-min (P<0.05); Significant difference compared with 5-min (P<0.05).

95 Figure 2. Number of Repetitions in Each Set with 1-Min, 2-Min, 3-Min, and 5-Min Rest Intervals for Machine Chest Fly. *Significant difference compared with Set 1; Significant difference compared with Set 2; #Significant difference compared with 2-min (P<0.05); Significant difference compared with 3-min (P<0.05); Significant difference compared with 5-min (P<0.05). The effect size data presented large magnitude for repetition reduction on both exercises and rest conditions (Table 2). The magnitude of reductions was more evident over the completion of the consecutive sets for all exercises in all rest interval conditions. Table 2. Effect Size from the Second Set of Each Exercise with the 1-Min, 2-Min, 3-Min, and 5-Min Rest Intervals. Exercise and Rest Conditions Set 2 Set 3 Bench Press 1-Min 3.42 (large) 5.02 (large) 2-Min 1.22 (large) 2.48 (large) 3-Min 0.80 (large) 1.23 (large) 5-Min 1.98 (large) 1.53 (large) Machine Chest Fly 1-Min 3.42 (large) 5.02 (large) 2-Min 3.15 (large) 6.42 (large) 3-Min 2.65 (large) 4.29 (large) 5-Min 0.98 (large) 1.53 (large) For the RPE data, significant increases were observed over the course of sets completion independently of the exercise modality. Moreover, higher values were found for the 1-min and the

2-min rest intervals starting as soon as the second set for the BP exercise (Table 2). For all other rest conditions in both exercises, significant values in RPE were evident only at last set. 96 Table 3. Rating of Perceived Exertion (RPE) for Each Set and Exercise for 1-Min, 3-Min, 5-Min Rest Interval (Median). Exercise and Rest Conditions Set 1 Set 2 Set 3 Bench press 1-Min 7 7.5* 8* 2-Min 6.5 7* 8* 3-Min 6 7 8* 5-Min 6 7 7* Machine Chest Fly 1-Min 6 7 8* 2-Min 6 6.5 8* 3-Min 6 6 7* 5-Min 6 6 7* *Significant difference to set 1; Significant difference to set 2; Significant difference to 5-min rest interval. DISCUSSION The findings in this study indicate that with regards to multi-joint BP exercise, longer rest periods (such as 3-min and 5-min) promote better consistency and a higher number of repetitions when compared with the shorter intervals (such as the 1-min and 2-min rest periods). Also, in regards to the MCF exercise, the 1-min, 2-min, and 3-min rest intervals resulted in significant reductions in total number of repetitions compared with the 5-min rest period. As to RPE, significant increases were shown over the succession of sets independent of the exercise modality. These findings can contribute for future recommendations due to the scarce multiple rest comparisons performed between multi-joint and single-joint exercises (BP and MCF). The American College of Sports Medicine (1) recommends a minimum of a 2-min to 3-min recovery between sets for multi-joint exercises and a minimum of 1-min to 2-min rest between sets for single-joint exercise. However, our data do not support the ACSM statement due to the very similar performance reduction pattern that we found on repetition number for both exercises modalities (multi-joint and single-joint). While ACSM recommends the 2-min rest condition when the goal is the development of strength or hypertrophy (1), the present study showed dramatic performance reductions with 2-min of recovery between sets for both exercises (multi-joint and single-joint exercise). Number of Repetitions Recently, only two studies investigated the influence of different rest intervals between sets for multi-joint and single-joint exercises (14,15). Senna et al. (14) compared repetition performance between multi-joint and single-joint exercises and analyzed the same muscles (pectoralis major and quadriceps femoris) for both methods. Fifteen trained men completed 12 sessions (4 exercises x 3 rest intervals). Each session consisted of 5 sets of 10 RM loads for the BP, leg

press, MCF, and leg extension exercises with 1-min, 3-min, and 5-min rest periods between sets. The results indicated a significantly higher value with 3-min and 5-min versus 1-min between sets for the BP. No significant differences were evident between 3-min and 5-min rest conditions. For other exercises (i.e., leg press, MCF, and machine leg extension), significant differences were reported between all rest conditions (1-min < 3-min < 5-min). For all exercises, consistent decreases in repetition performance (relative to the first set) were observed for all rest conditions, starting early from the second set for 1-min rest condition and late by the third set for the 3-min and 5-min rest periods. Senna et al. (15) compared the influence of different rests on multi-joint and single-joint exercises on repetition performance, perceived exertion, and blood lactate. All subjects completed four different experimental sessions. During each session, five sets of each exercise were executed with 10 RM loads to failure with the 1-min or 3-min rest interval. The authors found that 3-min rest protocol promoted greater total number of repetitions for BP and MCF compared to the shorter 1- min rest condition. Regarding the RPE, progressive elevations occurred after the third set of all conditions tested. For blood lactate concentrations, the multi-joint exercise (BP) elicited significant elevations immediately after and 15 min post-exercise compared to the baseline condition for both rest conditions (1-min and 3-min). As for the single-joint exercise (MCF), the authors found higher blood lactate values with the 1-min rest interval compared to the 3-min rest interval. The studies conducted by Senna et al. (14,15) partially corroborate the findings in the current study due to the similar pattern of repetitions performance found for different exercises with either the 1-min, 3-min, and 5-min recovery. Several rest periods were verified (1-min, 2-min, 3-min, and 5-min) and no important differences were observed in the performance patterns between both exercises (BC and MCF). However, we did found that the 3-min rest condition did not trigger a significant reduction in total number of repetitions for the single-joint exercise, which contrasted with Senna et al. (14,15). This outcome might have occurred due to the accumulated fatigue effect found by the previous 5 set protocol compared to the much shorter 3 set protocol from the current investigation. Several other previous studies focused on analyzing distinct rest periods on multi-joint exercises (8-12,17-19). The majority of these investigations found significant reductions in performance for several different recovery times (i.e., 1-min, 2-min, 3-min, and 5-min). For instance, Ratamess et al. (9) examined the effects of different rest periods on intensity, volume, and metabolic responses in the BP exercise. Eight trained men performed 10 randomized protocols with 5 BP sets at 75% or 85% of 1 RM for 10 repetitions and 5 repetitions, respectively. The authors then implemented several rest periods between sets (30-sec, 1-min, 2-min, 3-min, and 5-min) and found that the 30- sec and 1-min rest periods resulted in 15 to 55% reductions in the subjects intensity and volume (fifth < fourth < third < second < first set). For the 2-min rest period, the performance was maintained during the first and second sets, but decrease 8 to 29% from the third, fourth, and fifth sets. For the 3-min rest period, a volume reduction was noted in the fourth and fifth sets, (~21% lower than the first, second, and third sets). At 5-min, a reduction was observed only for the final fifth set. The authors found that the greatest reductions in performance occurred with the shortest recoveries and performance was maintained during third to fourth sets when a longer 3-min to 5- min rest period was conducted. These data are in accordance with the overall result of the present study when taking into account the multi-joint exercise outcomes. Moreover, a very similar pattern was found for the single-joint exercise, allowing for the observation of the same performance pattern between exercise modalities. 97

Rating of Perceived Exertion (RPE) The use of RPE to check the relative intensity of resistance exercise (4,5) has been shown to be helpful in understanding metabolic work of consecutive sets for the short 1-min rest interval for both multi-joint and single-joint exercises (14,15). In agreement with the earlier work, we found a significant increase in RPE values with consecutive sets for both multi-joint and single-joint exercise with significantly increased values for the shorter 1-min and 2-min rest conditions independently of the exercise mode (BC and MCF). Thus, short rest periods of 1-min and 2-min appears to enhance anaerobic glycolysis to compensate for the incomplete phosphocreatine resynthesis. The resulting feedback from this biochemical reaction may have an affect the muscle nociceptors with increased soreness sensation and effort perception (4,5). CONCLUSIONS The ability to maintain a high training intensity and volume is very important for strength development. Coaches and trainers must comprehend and apply scientific knowledge regarding the correct manipulation of resistance training variables in order to achieve specific goals throughout the sessions. The present study brings new understanding regarding rest interval and enhances the tools for professionals to manipulate this variable in order to achieve different training goals, directly affecting the number of repetitions during consecutive sets for both multi and single-joint exercises. These results indicate that repetition performance can be significantly affected and present reduced values by implementing shorter rest periods independently of the multi-joint and single-joint exercise modality. Although, the ideal rest between sets for multi-joint and single-joint exercise is still a controversial theme in the literature, we strongly recommend more studies that further investigate the relationships between different rest intervals on multi-joint and single-joint exercise on hormonal, metabolic and neural responses to better understand the associated phenomena as well as the pursuit of the optimal rest period length to achieve different training goals (i.e., strength and hypertrophy). 98 Address for correspondence: Gilmar Senna, Federal University of State of Rio de Janeiro, Xavier Sigaud, 290/401, Praia Vermelha, Rio de Janeiro, RJ, Brazil, 22290-180. Email: sennagw@gmail.com. REFERENCES 1. American College of Sports Medicine. Position stand on progression models in resistance exercise for healthy adults. Med Sci Sports Exerc. 2009;41:687-708. 2. Baechle TR, Earle RW. Essentials of Strength Training and Conditioning. (2nd Edition). Champaing, IL: Human Kinetics, 2000. 3. Cohen J. Statistical Power Analysis for the Behavioral Sciences. (2nd Edition). Hillsdale, NJ: Lawrence Erlbaum, 1988. 4. Lagally KM, Amorose AJ, Rock B. Selection of resistance exercise intensity using ratings of perceived exertion from the OMNI-RES. Percept Mot Skills. 2009;108:573-586.

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19. Willardson JM, Burkett LN. The effect of rest interval length on the sustainability of squat and bench press repetitions. J Strength Cond Res. 2006b;20:396-399. 100 Disclaimer The opinions expressed in JEPonline are those of the authors and are not attributable to JEPonline, the editorial staff or the ASEP organization.