IMPACT OF SHORT AND MODERATE ON THE ACUTE IMMUNOMETABOLIC EXHAUSTIVE STRENGTH EXERCISE: REST INTERVALS RESPONSE TO PART II JOSE GEROSA-NETO,1 FABRI´CIO E ROSSI,1 EDUARDO Z CAMPOS,1 BARBARA M.M ANTUNES,1 JASON M CHOLEWA,2 AND FABIO S LIRA1 Exercise and Immunometabolism Research Group, Department of Physical Education, Univer Estadual Paulista (UNESP), Presidente Prudente, SP, Brazil; and 2Department of Kinesiology, Recreation, and Sport Studies, Coastal Carolina University, Conway, South Carolina ABSTRACT Gerosa-Neto, J, Rossi, FE, Campos, EZ, Antunes, BMM, Cholewa, JM, and Lira, FS Impact of short and moderate rest intervals on the acute immunometabolic response to exhaustive strength exercise: Part II J Strength Cond Res 30(6): 1570–1576, 2016—The purpose of this study was to investigate the influence of short and moderate recovery intervals during heavy strength exercise on performance, inflammatory, and metabolic responses in recreational weightlifters Eight healthy subjects (age = 24.6 4.1 years) performed randomized sequences with different rest intervals: short = 90% of 1RM and 30 seconds rest allowed between sets; moderate = 90% of 1RM and 90 seconds rest allowed between sets All sequences of exercises were performed over sets until movement failure in the squat and bench press exercises, respectively Glucose, TNF-a, IL-6, IL-10, IL-10/TNF-a ratio, and nonester fatty acid concentrations were assessed at the baseline, immediately postexercise, post-15 and post-30 minutes We observed a statistically significant decrease after 30 seconds on maximum number of repetitions (p = 0.003) and total weight lifted (p = 0.006) after the bench press, and there was a marginal decrease in the squat (p = 0.055) The glucose concentrations showed a significant increase post15 minutes in the 30-second condition (pre-exercise = 86.1 9.1, immediately = 85.3 8.2, post-15 = 97.0 9.0, post30 = 87.1 5.3 mg/dl; p = 0.015); on the other hand, IL-10 increased post-30 minutes in the 90-second condition (preexercise = 18.2 12.7, immediately = 16.4 10.7, post-15 = 16.8 12.2, post-30 = 35.0 13.1 pg/ml; p , 0.001) In addition, the 90-second condition showed anti-inflammatory effects (as indicated by IL-10/TNF-a ratio: pre-exercise = Address correspondence to Fabrı´cio E Rossi, rossifabricio@yahoo com.br 30(6)/1570–1576 Journal of Strength and Conditioning Research Ó 2016 National Strength and Conditioning Association 1570 the 1.08 1.32, immediately = 1.23 1.20, post-15 = 1.15 1.14, post-30 = 2.48 2.07; p = 0.020) compared with the 30-second condition (pre-exercise = 1.30 2.04, immediately = 0.99 1.27, post-15 = 1.23 1.82, post-30 = 1.28 1.28; p = 0.635) Thus, we concluded that a moderate interval of recovery (90 seconds) during heavy strength exercise allowed higher workload, IL-10 levels, and IL-10/TNF-a ratio in recreational weightlifters KEY WORDS interval of recovery, inflammation, metabolism INTRODUCTION T he stimuli generated in strength training protocols cause changes in the production and release of hormones and cytokines because of an increase in energetic demand and skeletal muscle injury (3) The acute immunological response to training plays a role in energy metabolism (10), skeletal muscle repair and remodeling, and the anabolic/catabolic response, and may respond differently according the type of exercise, intensity, volume and recovery between exercise bouts (9,13) Philips et al (12) compared strength training sets on the same exercises with different intensities (2 sets of 12 repetitions followed by a third set to fatigue at 65% repetition maximum [1RM], and sets of repetitions and with a third set to fatigue at 85% 1RM) and observed increases in IL-6 concentrations after both intensities When the load volume is matched, IL-6 elevation is similar between different intensities (15) Recently, our group demonstrated the influence of interval length on immunometabolic responses in recreational weightlifters (13) Pooled IL-6 concentrations (i.e., cluster of all periods in each variable) were higher after sets at 70% of 1RM performed until exhaustion with 90-second recovery compared with 30-second recovery However, no increase was observed in TNF-a, IL-6, or IL-10 Thus, because muscle IL-6 release might be related with anti-inflammatory TM Journal of Strength and Conditioning Research Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited the TM Journal of Strength and Conditioning Research status and muscle protein synthesis (12), moderate intervals may be better to induce positive adaptations (13) The immunometabolic response to more intense strength training sets (i.e., 90% of 1RM) requires further investigation; however, especially because total volume (an important variable to immunometabolic alteration) decreases with higher intensities (15) and a higher metabolic demand may modify the anti-inflammatory status (3) Moreover, understanding the immunometabolic response in terms of substrate availability and adaptation during sets of heavy strength exercise is important to adjust/modify the strength training periodization to ensure the correct adaptation is being pursued because 90% of 1RM and 30–90 seconds of recovery interval is extensively used during strength training Thus, the purpose of this study was to investigate the influence of short (30-second) and moderate (90-second) recovery intervals during sets of heavy strength exercise performed until exhaustion on inflammatory and metabolic responses in recreational weightlifters Our hypothesis is that a high-intensity strength exercise session with moderate recovery intervals (90-second) can induce a positive inflammatory response compared with short recovery intervals (30-second) because of higher IL-10 levels that result from the higher metabolic demands METHODS Experimental Approach to the Problem To investigate the effect of different rest periods between sets (30 and 90 seconds) on the immunometabolic response, data were collected using a randomized and counterbalanced within-subjects design Subjects performed the exercise sessions at 72 hours intervals The test of 1RM was determined on nonconsecutive days, week before the exercise protocols for all subjects The blood samples were collected pre-exercise, immediately after exercise, and post15 minutes and post-30 minutes into recovery (Figure 1) Subjects Eight male subjects with strength training experience (.6 months) (1) voluntarily participated in this study All subjects performed weight training with a mean frequency of Figure Study design | www.nsca.com sessions per week for approximately hour per session Inclusion criteria for participation in the study were the following: age between 20 and 32 years, and no contraindications involving the cardiovascular system, muscles, joints, or bones of the lower limbs with regard to the practice of strength training This study was conducted in accordance with the Helsinki Declaration Approval for the study was obtained from the appropriate Institutional Review Board (IRB) Informed consent was obtained from all participants before their participation The study conforms to the Code of Ethics of the World Medical Association (approved by the ethics advisory board of Swansea University) and required players to provide informed consent before participation Procedures Anthropometric Measurements and Dietary Intake Assessment Anthropometry consisted of body weight and height measurements Height was measured on a fixed stadiometer of the Sanny brand with an accuracy of 0.1 cm and a length of 2.20 m Body weight was measured using an electronic scale (Filizola PL 50; Filizola Ltda., Brazil), with a precision of 0.1 kg Diet was not standardized; however, participants were required to eat hours before all testing sessions Participants were instructed by a nutritionist how to complete the food records and were required to record all foods consumed on the day of each testing session Nutrition data were analyzed for energy intake and macronutrient distribution using the NutWin software, version 1.5 (Programa de Apoio a` Nutric¸a˜o, Universidade Federal de Sa˜o Paulo, Brazil, 2002) Test of One Repetition Maximum One week before testing, the participants performed sets of 10–12 repetition in each exercise, times per week (Monday, Wednesday and Friday) for familiarization with equipment The test of 1RM was performed using the squat and bench press exercises The 1RM test consisted of minutes of warm-up (jogging), followed by the performance of set of 10 repetitions of each exercise at approximately 50% of the 1RM The load was increased gradually (10–15%) during the test until the participants were no longer able to perform the entire movement, and 3–5 attempts were allowed (1) For recovery, an interval of 3–5 minutes between attempts was given (1) No rest was allowed between the concentric and eccentric phases of the movement, and the participants were encouraged verbally to exert a maximum effort In addition, for better VOLUME 30 | NUMBER | JUNE 2016 | 1571 Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited Heavy Strength Exercise and Inflammatory Responses each half-squat repetition Two fitness professionals supervised all testing sessions TABLE Subject characteristics Variables Age (yr) Height (cm) Weight (kg) Fat mass (%) Fat free mass (%) Mean SD (n = 8) 25.2 178.1 76.4 18.3 77.2 6 6 4.1 10.4 7.7 6.1 5.7 control of the 1RM test procedures, a wooden seat with adjustable heights was placed behind the participant to keep the bar displacement and knee angle (;908) constant on Experimental Protocol At 72 hours after the 1RM test, subjects performed randomized exercise sessions separated by 72 hours interval Before the exercise sessions, minutes of warm-up (jogging) was performed During the exercise sessions, subjects were verbally encouraged to perform all sets until exhaustion in each exercise The exercise order for all sessions was squats followed by bench press In both conditions, subjects performed sets of squat and then sets of bench press using 90% of the 1RM In the short interval, 30 seconds (30-second) of rest was allowed between sets and exercises; whereas in the moderate interval, 90 seconds (90-second) of rest was allowed between Figure Comparison of the maximum number of repetitions at the squat (A), bench press (B), total weight lifted at the squat (C), bench press (D), and maximum number of repetitions in each series at the squat (E) and bench press (F) a = Tukey’s post hoc test with p-value # 0.05 compared with series-1; b = Tukey’s post hoc test with p-value # 0.05 compared with series-2 Student’s t-test for independent samples was performed and repeated measurements were conducted for the analyses when necessary 1572 the TM Journal of Strength and Conditioning Research Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited the TM Journal of Strength and Conditioning Research | www.nsca.com Figure Comparison of the IL-6 (A), IL-10 (B), TNF-a (C), and IL-10/TNF-a ratio (D) immediately after exercise (immediately), post-15 minutes, post30 minutes into recovery Two-way analysis of variance (condition time) with repeated measurements of the second factor sets and exercises All the sequences of exercises were performed for sets until movement failure for each exercise with normal speed (1-second eccentric and 1-second concentric actions with 1-second pause between each repetition) (16) The total number of repetitions performed was recorded for each set of each exercise and for all sequences and used to analyze workload and performance All the sequences of exercises were performed hours after prandial Blood Samples and Analysis Blood samples were collected at rest, immediately, 15 and 30 minutes after acute exercise sessions The blood samples (10 ml) were immediately allocated into two ml vacutainer tubes (Becton Dickinson, Juiz de Fora, Brazil) containing EDTA for plasma separation and into one ml dry vacutainer tube for serum separation The tubes were centrifuged at 3,000 RPM for 15 minutes at 48 C, and plasma and serum samples were stored at 2208 C until analysis Glucose was assessed through a commercial enzymatic kit (Labtest, Sa˜o Paulo, Brazil) Nonester fatty acid (NEFA) was assessed by a colorimetric method with a commercial kit (Wako Diagnostics, CA, USA) Cytokines (IL-6, IL-10, and TNF-a) were assessed using ELISA commercial kits (Affymetrix/eBioscience, Ambriex S/A, Brazil) IL-6, IL-10, TNF-a, and glucose were assessed using serum, and NEFA was assessed using plasma To eliminate interassay variance, all samples were analyzed in identical runs resulting in an intra-assay variance of ,7% Standard curve range for TNF-a (7.81–500 pg/ml), IL-6 (3.12–200 pg/ml) and IL-10 (4.68–300 pg/ml), NEFA (0.01–4.00 mEq/L), and for glucose reference standard was 100 mg/dl Statistical Analyses The data normality was verified using the Shapiro–Wilk test The comparison of the total weight lifted the maximum number of repetitions under the different conditions and food intake was analyzed using the Student’s t-test for independent samples The comparison of the maximum number of repetitions in each series was conducted by repeated measurements analyses and the differences in the glucose, NEFA and cytokines were calculated performing a 2-way repeated measure of ANOVA (group time) When a significant difference in group or interaction was observed, a Tukey’s post hoc test was conducted For all measured variables, the estimated sphericity was verified according to Mauchly’s W test, and the Greenhouse– Geisser correction was used when necessary Statistical significance was set at p # 0.05 The data were analyzed using the Biostat (version 5.0) RESULTS The mean SD values of the subjects’ characteristics are presented in Table Total food intake and macronutrient distribution hours before the test (expressed in kcal) were similar between conditions (30-second = 870.5 525.6 Kcal vs 90-second = 836.2 593.8 Kcal; p = 0.906) (carbohydrates: 30-second = 123.7 118.3 vs 90-second = 124.3 6.4 grams, p = 0.992; protein: VOLUME 30 | NUMBER | JUNE 2016 | 1573 Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited Heavy Strength Exercise and Inflammatory Responses post-15 = 16.8 12.2 pg$ml21, and post-30 = 35.0 13.1 pg$ml21; p , 0.001) but without significant differences in the 30-second condition (preexercise = 17.0 10.0 pg$ml21, immediately = 16.6 10.9 pg$ml21, post-15 = 15.3 10.0 pg$ml21, and post-30 = 23.1 15.1 pg$ml21; p = 0.091) In addition, the IL-10/ TNF-a ratio showed increases only at post-30 in the 90second condition (pre-exercise = 1.08 1.32, immediately = 1.23 1.20, post-15 = 1.15 1.14, post-30 = 2.48 2.07; p = 0.020), but not in the 30second condition (pre-exercise = 1.30 2.04, immediately = 0.99 1.27, post-15 = 1.23 1.82, post-30 = 1.28 1.28; p = 0.635) Glucose increased in the 30-second condition at 15 minutes after exercise (pre-exercise = 86.1 9.1 mg$dl21, immediately = 85.3 8.2 mg$dl21, post-15 = 97.0 9.0 mg$dl21, and post-30 = Figure Comparison of the glucose (A) and NEFA (B) immediately after exercise (immediately), post87.1 5.3 mg$dl21; p = 15 minutes, post-30 minutes into recovery Two-way analysis of variance (condition time) with repeated 0.015) but there were no sigmeasurements of the second factor nificant differences in the 90-second condition (preexercise = 84.2 8.5 mg$dl21, immediately = 89.6 13.1 mg$dl21, post-15 = 30-second = 45.0 27.7 vs 90-second = 38.1 32.8 90.6 11.4 mg$dl21, and post-30 = 86.3 13.2 mg$dl21; grams, p = 0.657; lipids: 30-second = 18.1 10.1 vs p = 0.758) There were no significant differences between 90-second = 24.9 11.1 grams, p = 0.210) time and condition for TNF-a and NEFA, but there was Figure presents the maximum number of repetition and a tendency in IL-6 during 30-second condition There total weight lifted during squat (Figures 2A, C) and bench were no interactions (time condition) for any of the press (Figures 2B, D) in both conditions Figures 2E, F variables analyzed (Figure 4) showed the volume decrement during the sets of squat and bench press during 30-second and 90-second, respecDISCUSSION tively There were significant differences between conditions The aim of the present study was to investigate the effects of for maximal number of repetitions (30 seconds = 8.6 2.7 short (30 seconds) and moderate (90 seconds) recovery 90 seconds = 14.4 3.8 repetitions) and total weight lifted intervals during sets of heavy strength exercise on inflam(30 seconds = 650.4 224.9 90 seconds = 1.080.5 matory and metabolic responses in recreational weightlifters 305.3 kg) in the bench press; however, there was a marginal The main findings of the present study were that (a) both decrease in squat for maximal number of repetitions (30 exercise sessions did not change IL-6, TNF-a, and NEFA; seconds = 19 9.7 90 seconds = 32 14.5 repetitions) (b) 30-second induced a greater increase in glucose concenand total weight lifted (30 seconds = 3.253.5 1.577.8 90 trations 15 minutes after exercise; and (c) 90-second proseconds = 5.926.8 3.255.4 kg) moted an increase in IL-10 concentrations and the IL-10/ The cytokines are presented in Figure IL-10 increased TNF-a ratio in relation to baseline during heavy strength at post-30 in the 90-second condition (pre-exercise = 18.2 exercise in recreational weightlifters 12.7 pg$ml21, immediately = 16.4 10.7 pg$ml21, 1574 the TM Journal of Strength and Conditioning Research Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited the TM Journal of Strength and Conditioning Research When analyzing the inflammatory responses, neither condition affected the IL-6 or TNF-a concentrations Lira et al (6) analyzed repeated efforts of high intensity (Wingate test) for upper and lower limbs in judo athletes and did not find significant changes in IL-6 and TNF-a The absence of change in IL-6 and TNF-a in the present study and Lira et al (6) may be attributed, in part, to low exercise volumes Thus, it seems that IL-6 increase is dependent on exercise volume since we found that IL-6 was enhanced after a similar exhaustive protocol at 70% of 1RM (2,13) Muscle-derived IL-6 exerts both a metabolic and immunological effect, increasing glucose uptake and anti-inflammatory function, and decreasing TNF-a concentration (11) Steensberg et al (14) tested if infusion of plasma IL-6 induces an antiinflammatory status in young, healthy individuals and did not observe enhanced levels of the proinflammatory cytokine (TNF-a) but did observe increased plasma levels of anti-inflammatory cytokines (IL-1 receptor agonist [IL-1ra] and IL-10) compared with saline infusion The same study also found IL-6 induced an increase in cortisol Given the low volume in both conditions (30 and 90 seconds) and high intensity (90% of 1RM), there may not have sufficient volume to stimulate IL-6 in this study compared with the higher volumes used in our 70% study This may also explain the difference in the glucose response observed between studies Contrary to our previous findings (13) that used sets at 70% of 1RM performed until exhaustion with the same interval recovery as in this study (90- against 30-second), the 30-second condition exhibited greater glucose levels than 90-second The anaerobic metabolic pathways of phosphocreatine (ATP-CP) and glycolysis are predominantly used to support the contractile activity of the muscles in this type of exercise; however, short intervals of recovery not provide sufficient time for complete creatine phosphate resynthesis leading to a higher glycolytic contribution, elevations in intracellular [H+], and great utilization of glycogen stores, stimulating its liberation Moderate rest intervals (90-second) increased IL-10 and IL-10/TNF-a ratio after 30 minutes when compared with pre-exercise values These results disagree with our previous findings because no difference was found in IL-10 and IL10/TNF-a ratio (13) Izquierdo et al (3) demonstrated IL-10 concentrations increased following sets until movement failure to 10 RM with 120 seconds of rest between the sets in male subjects when compared with pretraining condition Because the 90-second condition performed a higher exercise volume than 30-second (Figure 2), the higher metabolic demand during the exercise session likely influenced the IL10 response (2) Currently, the IL-10/TNF-a ratio has been adopted as an inflammatory status indicator, and low levels are associated with poor prognoses and increased susceptibility to various morbidities (4,5) Nikseresht et al (8) compared the changes of this ratio in obese subjects after 12 weeks of training using high-intensity intermittent exercise (treadmill, 4 minute; | www.nsca.com 80–90% of maximum heart rate) and strength training with nonlinear periodization (40–65 minutes, 3 week; mild, moderate, and severe) They showed that a significant increase in the IL-10/TNF-a ratio was accompanied by significant reductions in fat mass and serum insulin concentrations and also improved the sensitivity to insulin’s action (HOMA-IR) Our group recently found that sets of 70% 1RM with 30-second and 90-second recovery did not increase IL-10 concentrations or the IL-10/TNF-a ratio (13) This may reflect that within high-intensity exercise (90% of 1RM) and moderate recovery interval (90-second), there is an increased anti-inflammatory response The higher IL-10 concentration blocks the possible effects of TNF-a, whereas the IL-10/TNF-a ratio is increased more in the trained subject compared with the sedentary subject (7) This regulation favors the anti-inflammatory environment, and it can be one of the mechanisms through which chronic exercise increases anti-inflammatory response Although the present study adds data regarding the antiinflammatory response (higher IL-10 levels and IL-10/ TNF-a ratio) during heavy strength exercise, some limitations in this study should be considered, such as the volume discrepancy between conditions It is possible that if repetition volume was the same, the immunometabolic response would be also similar; however, this is yet to be tested Further research should evaluate the effects of short and moderate rest intervals on the immunometabolic response when the volume is matched between conditions In summary, differing rest intervals promotes diverging immunometabolic responses in recreational weightlifters, with 90-second promoting an anti-inflammatory environment More research is needed to investigate the interaction between heavy chronic training, the immunological response, and adaptation PRACTICAL APPLICATIONS This study demonstrates to coaches and trainers who employ heavy strength exercise that moderate recovery intervals between sets promote an increased antiinflammatory response (IL-10 and IL-10/TNF-a), and together with a higher overall volume achieved may better promote the hypertrophic and adaptive process when training with heavy loads ACKNOWLEDGMENTS Fabio Santos Lira thanks Fapesp for their support (2013/ 25310–2) The authors declare that they have no conflict of interest REFERENCES American College of Sports Medicine L Kaminsky, ed ACSM’s Guidelines for Exercise Testing and Prescription 7th ed Baltimore, Maryland, 2006 Gleeson, M Immune function in sport and exercise J App Physiol 103: 693–699, 2007 VOLUME 30 | NUMBER | JUNE 2016 | 1575 Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited Heavy Strength Exercise and Inflammatory Responses Izquierdo, M, Iban˜ez, J, Calbet, JA, Navarro-Amezqueta, I, Gonzalez-Izal, M, Idoate, F, Haăkkinen, K, Kraemer, WJ, PalaciosSarrasqueta, M, Almar, M, and Gorostiaga, EM Cytokine and hormone responses to resistance training Eur J Appl Physiol 107: 397–409, 2009 Kaur, K, Sharma, AK, Dhingra, S, and Singal, PK Interplay of TNFa and IL-10 in regulating oxidative stress in isolated adult cardiac myocytes J Mol Cell Cardiol 41: 1023–1030, 2006 Leonidou, L, Mouzaki, A, Michalaki, M, DeLastic, AL, Kyriazopoulou, V, Bassaris, HP, and Gogos, CA Cytokine production and hospital mortality in patients with sepsis-induced stress hyperglycemia J Infect 55: 340–346, 2007 Lira, FS, Panissa, VL, Julio, UF, and Franchini, E Differences in metabolic and inflammatory responses in lower and upper body highintensity intermittent exercise Eur J Appl Physiol 115: 1467–1474, 2015 Lira, FS, Rosa, JC, Zanchi, NE, Yamashita, AS, Lopes, RD, Lopes, AC, Batista, ML Jr, and Seelaender, M Regulation of inflammation in the adipose tissue in cancer cachexia: Effect of exercise Cell Biochem Funct 27: 71–75, 2009 Nikseresht, M, Agha-Alinejad, H, Azarbayjani, MA, and Ebrahim, K Effects of nonlinear resistance and aerobic interval training on cytokines and insulin resistance in sedentary men who are obese J Strength Cond Res 28: 2560–2568, 2014 Paulsen, G, Mikkelsen, UR, Raastad, T, and Peake, JM Leucocytes, cytokines and satellite cells: What role they play in muscle 1576 the damage and regeneration following eccentric exercise? 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