Publications by authors named "Tacito P Souza-Junior"

16 Publications

  • Page 1 of 1

Rest-pause and drop-set training elicit similar strength and hypertrophy adaptations compared to traditional sets in resistance-trained males.

Appl Physiol Nutr Metab 2021 Jul 14. Epub 2021 Jul 14.

Federal University of Parana, 28122, Metabolism, Nutrition and Resistance Training Research Group (GPMENUTF), Department of Physical Education, Curitiba, PR, Brazil.

The present paper aimed to compare the effect of drop-set (DS) and rest-pause (RP) systems versus traditional resistance training (TRT) with equalized total training volume on maximum dynamic strength (1RM) and thigh muscle thickness (MT).Twenty-eight resistance-trained males were randomly assigned to either RP (n = 10), DS (n = 9) or TRT (n = 9) protocols performed twice a week for 8 weeks. 1RM and MT of the proximal, middle and distal portions of the lateral thigh were assessed at baseline and post intervention.A significant time x group interaction was observed for 1RM (P = 0.025) in the barbell back squat after 8-weeks. Post hoc comparisons revealed that RP promoted higher 1RM than TRT (P = 0.001); no statistical differences in strength were observed between the other conditions. A significant main effect of time was revealed for MT at the proximal (P = 0.0001) and middle (P = 0.0001) aspects of the lateral thigh for all training groups; however, the distal portion did not show a time effect (P = 0.190). There were no between-group interactions for MT. Our findings suggest that RP promotes slightly superior strength-related improvements compared to TRT, but hypertrophic adaptations are similar between conditions. Novelty bullets • Rest-pause elicited a slightly superior benefit for strength adaptations compared to traditional resistance training. • Resistance training systems do not promote superior hypertrophic adaptations when total training volume is equalized. • Muscle thickness in distal portion of thigh are similar to baseline. Although modest, effect sizes tended to favor rest-pause.
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http://dx.doi.org/10.1139/apnm-2021-0278DOI Listing
July 2021

Effects of Creatine Supplementation on Properties of Muscle, Bone, and Brain Function in Older Adults: A Narrative Review.

J Diet Suppl 2021 Jan 27:1-18. Epub 2021 Jan 27.

Research Group on Metabolism, Nutrition and Strength Training, Federal University of Paraná, Curitiba, PR, Brazil.

Aging is associated with reductions in muscle and bone mass and brain function, which may be counteracted by several lifestyle factors, of which exercise appears to be most beneficial. However, less than 20% of older adults (> 55 years of age) adhere to performing the recommended amount of resistance training (≥ 2 days/week) and less than 12% regularly meet the aerobic exercise guidelines (≥ 150 min/week of moderate to vigorous intensity aerobic exercise) required to achieve significant health benefits. Therefore, from a healthy aging and clinical perspective, it is important to determine whether other lifestyle interventions (independent of exercise) can have beneficial effects on aging muscle quality and quantity, bone strength, and brain function. Creatine, a nitrogen containing organic compound found in all cells of the body, has the potential to have favorable effects on muscle, bone, and brain health (independent of exercise) in older adults. The purpose of this narrative review is to examine and summarize the small body of research investigating the effects of creatine supplementation alone on measures of muscle mass and performance, bone mineral and strength, and indices of brain health in older adults.
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http://dx.doi.org/10.1080/19390211.2021.1877232DOI Listing
January 2021

Association study of performance-related polymorphisms in Brazilian combat-sport athletes highlights variants in the gene.

Physiol Genomics 2021 02 21;53(2):47-50. Epub 2020 Dec 21.

Laboratory of Applied Nutrition and Metabolism, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.

Combat sports are an intermittent sport, with mixed anaerobic and aerobic energy production. Here, we investigated whether the polymorphisms that have been previously suggested as genetic markers for endurance or power phenotypes were associated with combat-sport athletic status. A total of 23 previously reported performance-related polymorphisms were examined in a cohort of 1,129 Brazilian individuals (164 combat-sport athletes and 965 controls), using a case-control association study. We found that the GA-binding protein transcription factor subunit beta 1 () gene (also known as nuclear respiratory factor 2; ) was associated with athletic status, with the minor G (rs7181866) and T (rs8031031) alleles overrepresented in athletes ( ≤ 0.003), especially among world-class athletes ( ≤ 0.0002). These findings indicate that single-nucleotide polymorphisms (SNPs) within the gene increase the likelihood of an individual being a combat-sport athlete, possibly because of a better mitochondrial response to intermittent exercises.
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http://dx.doi.org/10.1152/physiolgenomics.00118.2020DOI Listing
February 2021

Training Programs Designed for Muscle Hypertrophy in Bodybuilders: A Narrative Review.

Sports (Basel) 2020 Nov 18;8(11). Epub 2020 Nov 18.

Metabolism, Nutrition and Resistance Training Research Group, Federal University of Paraná, Curitiba 81531-980, Brazil.

Bodybuilding is a sport that requires adequate training strategies in order to maximize skeletal muscle hypertrophy. The purpose of the present review was to perform a narrative assessment of the training routines designed for muscle hypertrophy used by bodybuilders. A search was carried out in the databases Pubmed/MEDLINE, Scielo, EBSCO, LILACS, SportDiscus, Web of Science, and CINAHL with the words "Resistance training" and "hypertrophy" in bodybuilders and their variations that involve the respective outcomes. Fourteen studies were identified that investigated the long-term training routines of bodybuilders. These studies demonstrate a pattern in the training organization, whereby there is a separation of training into four distinct periods: off-season, pre-contest, peak week, and post-contest. Each period has a specific spectrum of intensity load, total training volume, and exercise type (multi- or single-joint). We conclude that bodybuilding competitors employed a higher intensity load, lower number of repetitions, and longer rest intervals in the off-season than pre-contest.
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http://dx.doi.org/10.3390/sports8110149DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7698840PMC
November 2020

Effect of 12 Weeks of Resistance Training on Motor Coordination and Dynamic Balance of Older Woman.

Rejuvenation Res 2021 Jun 11;24(3):191-197. Epub 2020 Dec 11.

Research Group on Metabolism, Nutrition and Strength Training, Federal University of Paraná, Curitiba, Brazil.

Resistance training (RT) is considered a viable strategy to enhance the autonomy and functionality of older populations. We randomized 49 older women (64.2 ± 3.8) into one of two groups: an intervention group (IG) ( = 29) that performed regimented RT or a nontraining control group (CG) ( = 20). The RT protocol was carried out three times a week for both the upper and lower limbs over a 12-week study period. A 30-second arm flexion test was used to test upper limb endurance and a 30-second chair stand test was used to analyze lower limb endurance. Dynamic balance was tested by a Y balance test normalized by leg length. A Soda Pop test was employed to analyze coordination. Results showed significant improvements in IG versus CG in both upper limb (19.50 ± 1.52 vs. 11.40 ± 2.87,  = 0.001) and lower limb muscular endurance (14.90 ± 3.10 vs. 26.56 ± 3.17,  = 0.001). Moreover, the training group showed superior improvements in anterior and posterolateral balance compared to CG (63.9% ± 3.1% to 70.2 ± 2.1 and 88.1 ± 3.9 to 94.2 ± 2.7 with  = 0.001, respectively). There were no significant differences in coordination outcomes between groups. In conclusion, we demonstrate that RT is effective in developing muscular endurance and dynamic balance in postmenopausal women, but does not influence muscular coordination in the measures studied. Study registered in the Brazilian Registry Clinical Trials Registry (No. RBR-7MZ2KR).
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http://dx.doi.org/10.1089/rej.2020.2339DOI Listing
June 2021

Reduced Dose of Beta-Alanine Is Sufficient to Maintain Performance in Repeated Sprints.

J Strength Cond Res 2020 Aug 21. Epub 2020 Aug 21.

Research Group on Metabolism, Nutrition and Strength Training, Federal University of Paraná, Curitiba, Brazil.

Zandona, BA, Ramos, RA, de Oliveira, CdS, McAnulty, SR, Ferreira, LHB, Smolarek, AC, Enes, AAN, Urbinati, KMdSS, Aragon, AA, Schoenfeld, BJ, and de Souza Junior, TP. Reduced Dose of Beta-Alanine Is Sufficient to Maintain Performance in Repeated Sprints. J Strength Cond Res XX(X): 000-000, 2020-Beta-alanine (BA) supplementation has been shown to be effective in improving physical performance by increasing carnosine concentration. However, it is still necessary to know the effect of a maintenance dose on performance. Thus, this study aimed to investigate the effects of a maintenance dose of BA supplementation on performance. Forty-four anaerobically trained men with 23.9 ± 3.8 years of age, 176.0 ± 0.05 cm height, 81.2 ± 7.5 kg body mass, and 15.5 ± 2.9% of body fat performed a cycle ergometer test consisting of 4 sprints of 30 s with 4 minutes of active recovery. The study comprised 3 phases: (a) presupplementation, (b) supplementation with 6.4 g·d BA or placebo, and (c) postsupplementation with a maintenance dose of 1.2 g·d of BA or interruption of supplementation. Data were analyzed using generalized estimated equations with a priori 0.05 level of significance. The placebo group and interruption group presented a lower power (7.28 ± 0.66 and 7.71 ± 0.42 W·kg vs. 8.04 ± 0.84 and 9.25 ± 1.18 W·kg, respectively; p < 0.05) during the third sprint in postsupplementation, whereas the maintenance group maintained the required power (7.47 ± 1.03 vs. 8.74 ± 1.07 W·kg; p > 0.05). The placebo group also presented higher percentage of fatigue (44.5% ± 12.3 and 44.8% ± 7.7 vs. 37.6 ± 7.2%; p = 0.021) and higher subjective perception of exertion (8.92 ± 0.90 vs. 8.00 ± 1.60; p = 0.028). Therefore, the maintenance dose of 1.2 g·d BA was effective in maintaining performance, whereas a reduction in performance was observed after supplementation interruption.
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http://dx.doi.org/10.1519/JSC.0000000000003715DOI Listing
August 2020

Immunological Responses to a Brazilian Jiu-Jitsu High-Intensity Interval Training Session.

J Hum Kinet 2019 Nov 30;70:115-124. Epub 2019 Nov 30.

Faculty of Biomedical Sciences, Metrocamp College, Campinas, SP, Brazil.

The objective of the study was to characterize immunological responses to a Brazilian Jiu-Jitsu high-intensity interval training session. Neuromuscular function, blood, and salivary samples were obtained after a Brazilian Jiu-Jitsu high-intensity interval training session. Saliva and blood samples were collected at Pre- (before the warm-up) and immediately Post-training. Neuromuscular function was evaluated by lower body muscle testing. The horizontal countermovement jump was performed at Pre (after the warm-up) and immediately Post blood and saliva collection, and approximately 5 minutes Post-training. The horizontal countermovement jump performance did not present any significant changes Post-training, while blood leukocytes, urea, IgA and salivary alpha-amylase showed a significant increase. Salivary alpha-amylase activity increased more than six times immediately Post compared to Pre-training. Saliva volume, secretion rate, and uric acid were not significantly different between Pre and Post condition. A Brazilian Jiu-Jitsu high-intensity interval training session elicited an increase in the blood cells responsible for antibody production and muscle damage adaptation after exercise. On the other hand, neuromuscular performance was not significantly affected Post-training, suggesting that immunological and performance responses were not necessarily associated.
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http://dx.doi.org/10.2478/hukin-2019-0051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6942484PMC
November 2019

High doses of sodium bicarbonate increase lactate levels and delay exhaustion in a cycling performance test.

Nutrition 2019 04 13;60:94-99. Epub 2018 Oct 13.

Research Group on Metabolism, Nutrition and Strength Training, Department of Physical Education, Federal University of Parana, Curitiba, Brazil; Appalachian State University, Department of Health and Exercise Science, Appalachian State University, Boone, North Caroline, USA.

Objectives: It is well established that ingestion of sodium bicarbonate (NaHCO) causes metabolic alkalosis. However, there is no consensus in terms of optimal NaHCO doses leading to enhanced performance. This study aimed to determine the effects of different NaHCO doses on performance and lactate clearance in non-professional cyclists.

Methods: Twenty-one cyclists performed the following three double-blind trials: 1) ingestion of 0.3 g · kg body weight (BW) of placebo; 2) ingestion of 0.1 g · kg BW NaHCO plus 0.2 g · kg BW placebo (0.1 BC); and 3) ingestion of 0.3 g · kg BW NaHCO (0.3 BC). Performance was evaluated after warm-up on the bike followed by a performance test until exhaustion. Lactate levels were monitored in blood samples before and immediately after performance tests.

Results: Lactate levels in the blood were significantly higher after exercise in 0.3 BC and 0.1 BC (15.12 ± 0.92 versus 10.3 ± 1.22 and 13.24 ± 0.87 versus 10.3 ± 1.22 mmol/L; P < 0.05) compared with control. Significant improvements in performance were only identified in 0.3 BC group (76.42 ± 2.14; P = 0.01).

Conclusions: The present study found that 0.3 g · kg BW NaHCO is effective in improving performance and improving blood lactate levels in cyclists compared with control and 0.1 g · kg BW NaHCO
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http://dx.doi.org/10.1016/j.nut.2018.09.018DOI Listing
April 2019

Effect of low dose, short-term creatine supplementation on muscle power output in elite youth soccer players.

J Int Soc Sports Nutr 2017 7;14. Epub 2017 Feb 7.

Department of Physical Education, Research Group on Metabolism, Nutrition and Strength Training, Curitiba, Brazil.

Background: To determine the effects of a low dose, short-term Creatine monohydrate (Cr) supplementation (0.03 g.kg.d during 14 d) on muscle power output in elite youth soccer players.

Methods: Using a two-group matched, double blind, placebo-controlled design, nineteen male soccer players (mean age = 17.0 ± 0.5 years) were randomly assigned to either Cr ( = 9) or placebo ( = 10) group. Before and after supplementation, participants performed a 30s Wingate Anaerobic Test (WAnT) to assess peak power output (PPO), mean power output (MPO), fatigue index (FI), and total work.

Results: There were significant increases in both PPO and MPO after the Cr supplementation period ( ≤ 0.05) but not the placebo period. There were also significant increases in total work, but not FI, after the Cr supplementation and placebo periods ( ≤ 0.05). Notably, there were differences in total work between the Cr and placebo groups after ( ≤ 0.05) but not before the 14 d supplementation period.

Conclusion: There is substantial evidence to indicate that a low-dose, short-term oral Cr supplementation beneficially affected muscle power output in elite youth soccer players.
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http://dx.doi.org/10.1186/s12970-017-0162-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5296953PMC
January 2018

Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity.

Appl Physiol Nutr Metab 2017 Jul 9;42(7):694-699. Epub 2017 Feb 9.

a Department of Health and Exercise Science, Appalachian State University, 111 Rivers Street, Boone, NC USA.

Dehydration is a common event associated with exercise. However, few studies have examined the effects of dehydration on plasma redox status in humans. Eighty-two athletes were recruited and baseline anthropometrics and blood samples were obtained. Athletes then engaged in a dehydration protocol, training until 3% of preweight body mass was lost. Athletes returned to the lab and had postdehydration blood collected. Athletes then consumed an isotonic drink until pre-exercise body weight was reestablished. Blood was then recollected (1 h post full rehydration (PFR)). Samples were centrifuged and the plasma snap frozen in liquid nitrogen and stored at -80 °C. Lipid and protein oxidative stress was determined by measuring F-isoprostanes and protein carbonyls (PC), respectively. Antioxidant capacity was determined by the ferric reducing ability of plasma (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. Plasma osmolality was determined using an osmometer. Statistical analysis utilized a 1-way ANOVA with posthoc testing. Values are reported as mean ± SD. Plasma osmolality was significantly elevated immediately postdehydration (p ≤ 0.001) but decreased to baseline at PFR. Plasma TEAC increased immediately postdehydration and at PFR (p ≤ 0.001). FRAP increased immediately postdehydration (p ≤ 0.001) and decreased to below baseline at PFR (p ≤ 0.05). Conversely, F-isoprostanes declined significantly from baseline to immediately postdehydration and then significantly rose at PFR (p ≤ 0.001), whereas PC declined at PFR (p ≤ 0.01). This study indicates that dehydration and exercise cause a significant increase in plasma osmolality and antioxidant potential immediately postexercise. We propose dehydration significantly elevates antioxidant concentration which suppresses F-isoprostanes and PC.
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http://dx.doi.org/10.1139/apnm-2016-0701DOI Listing
July 2017

Effect of 1 Repetition Maximum, 80% Repetition Maximum, and 50% Repetition Maximum Strength Exercise in Trained Individuals on Variations in Plasma Redox Biomarkers.

J Strength Cond Res 2017 Sep;31(9):2489-2497

1Institute of Physical Activity and Sports Science (ICAFE), Cruzeiro do Sul University, São Paulo, Brazil; 2Department of Physical Education, Research Group on Metabolism, Nutrition and Strength Training, Federal University of Parana, Curitiba, Brazil; 3Department of Health and Exercise Science, Appalachian State University, Boone, North Carolina; and 4Free Radical Metabolism Group, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina.

Polotow, TG, Souza-Junior, TP, Sampaio, RC, Okuyama, AR, Ganini, D, Vardaris, CV, Alves, RC, McAnulty, SR, and Barros, MP. Effect of 1RM, 80%RM, and 50%RM strength exercise in trained individuals on variations in plasma redox biomarkers. J Strength Cond Res 31(9): 2489-2497, 2017-For decades, scientists have examined the participation of oxygen/nitrogen species in anaerobic-like exercises, especially weightlifting and resistance exercises. The balance between the production of oxyradicals and antioxidant responses during anaerobic-like exercises is essential to assure adaptation to the physiological benefits of strength training and to prevent chronic harmful effects. The aim of this study is to examine the hypothesis that different weight loads (1 repetition maximum (RM), 80%RM, and 50%RM) lifted until exhaustion could impose distinct oxidative insults and elicit diverse antioxidant responses in plasma of young trained subjects. Glucose (+10%), lactate (+65%), urea (+30%), free iron (+65%), reduced/oxidized glutathione (+14 and +23%, respectively), and xanthine oxidase activity (2.2-fold) significantly increased after the 1RM test, whereas plasma antioxidant capacity dropped by 37%. When lower weight loads were applied (80%RM and 50%RM tests), heme-iron (+15 and +20%, respectively) became the prevalent pro-oxidant, although glutathione responses were only detected after 80%RM (+14%). Lactate concentration in plasma continuously increased, by 2.9-fold (80%RM) and 3.6-fold higher (50%RM test). We demonstrated that 1RM tests significantly diminish the antioxidant capacity of plasma because of iron overload, whereas 80%RM tests require higher involvement of glutathione molecules to counteract heme-iron oxidative insult. Mild redox imbalances promoted by heme-iron were found in plasma after 50%RM. Although we did not observe overall changes in muscle damage in young trained subjects, we cannot exclude the need for specific antioxidant supplementation depending on the strength protocols applied, especially for less responsive groups, such as sedentary and elderly populations.
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http://dx.doi.org/10.1519/JSC.0000000000001703DOI Listing
September 2017

The effects of strength training on cognitive performance in elderly women.

Clin Interv Aging 2016 1;11:749-54. Epub 2016 Jun 1.

Research Group on Metabolism, Nutrition and Strength Training, Department of Physical Education, Federal University of Parana, Curitiba, Brazil; Department of Health and Exercise Science, Appalachian State University, Boone, NC, USA.

Aging is a degenerative process marked by recognized functional, physiological, and metabolic impairments, such as dynapenia and diminished cognitive capacity. Therefore, the search for innovative strategies to prevent/delay these physiological and cognitive disorders is essential to guarantee the independence and life quality of an elderly population. The aim of this work is to verify the effect of a 12-week resistance exercise program on the general physical aptitude and cognitive capacities of elderly and sedentary women. Twenty-nine women (65.87±5.69 years) were divided into two groups. The control group was composed of eight elderly women who met the same inclusion criteria of the study and the strength training group was composed of 29 elderly women who were subjected to a resistance exercise program defined by 12 upper and lower limb exercises combined in 3×10 repetitions with 1-minute interval between repetitions and two resting minutes between exercises (three times/week). Weight loads were fixed between 60% and 75% of the apparent 1 repetition maximum, which was estimated by the test of 10 maximum repetitions. The direct curl was performed for upper body strength evaluation with 2.3 kg dumbbells for 30 seconds, whereas the chair test was used for lower body evaluation (total sit-stand movements in 30 seconds). The cognitive capacities of subjects were evaluated by "The Montreal Cognitive Assessment" questionnaire. After 12 weeks, the elderly group showed significant increases in the average upper body strength (58%), lower body strength (68%), and cognitive capacity (19%). The present study demonstrated that regular resistance exercises could provide significant gains on the upper and lower body strength concomitant to positive improvements on cognitive capacities of elderly women, bringing enhanced life quality.
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http://dx.doi.org/10.2147/CIA.S102126DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4896469PMC
February 2017

Tai Chi and Kung-Fu practice maintains physical performance but not vascular health in young versus old participants.

Phys Sportsmed 2016 17;44(2):184-9. Epub 2016 Mar 17.

a Department of Health, Leisure, and Exercise Science , Appalachian State University , Boone , NC , USA.

Objectives: Kung-Fu and Tai Chi along with other martial arts are gaining popularity but studies examining the benefits of martial arts on physical fitness, vascular health, nutrition, and psychological wellness are limited. Aging is associated with declines in these health components. The objectives of this study were to examine whether Tai Chi and Kung-Fu training would maintain physical fitness, vascular health, and psychological wellness components on older versus younger practitioners.

Methods: Seventeen subjects were recruited and divided into Young (age <40 years, n=9) and Old (age 40 years and above, n=8). Participants reported twice for health screens, vascular and nutrition assessment, and fitness tests. Mean differences were compared between groups for all tests using Student's t-tests.

Results: Age, months of practice, systolic blood pressure, and cardiovascular augmentation index were significantly greater in Old versus Young (p=0.001, p=0.007, p=0.049, and p=0.011, respectively). Psychologically, old practitioners experienced greater sleep interference (p=0.035) and overall pain (p=0.036). No other differences existed for any variable.

Conclusion: Our study indicates that the practice of Tai Chi and Kung-Fu maintains physical fitness in older compared to younger practitioners. However, age associated changes in cardiovascular stiffness, systolic blood pressure, and pain were not prevented.
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http://dx.doi.org/10.1080/00913847.2016.1158623DOI Listing
November 2016

The Use of Session RPE to Monitor the Intensity of Weight Training in Older Women: Acute Responses to Eccentric, Concentric, and Dynamic Exercises.

J Aging Res 2014 13;2014:749317. Epub 2014 Apr 13.

Department of Physical Education, Federal University of Parana, Caixa Postal 92, JD Botânico, 80215-370 Curitiba, PR, Brazil.

The rating of perceived exertion (RPE) is ability to detect and interpret organic sensations while performing exercises. This method has been used to measure the level of effort that is felt during weight-training at a given intensity. The purpose of this investigation was to compare session RPE values with those of traditional RPE measurements for different weight-training muscle actions, performed together or separately. Fourteen women with no former weight-training experience were recruited for the investigation. All participants completed five sessions of exercise: familiarization, maximum force, concentric-only (CONC-only), eccentric-only (ECC-only), and dynamic (DYN = CONC + ECC). The traditional RPE method was measured after each series of exercises, and the session RPE was measured 30 min after the end of the training session. The statistical analyses used were the paired t-test, one-way analysis of variance, and repeated measures analysis of variance. Significant differences between traditional RPE and session RPE for DYN, CONC, and ECC exercises were not found. This investigation demonstrated that session RPE is similar to traditional RPE in terms of weight-training involving concentric, eccentric, or dynamic muscle exercises, and that it can be used to prescribe and monitor weight-training sessions in older subjects.
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http://dx.doi.org/10.1155/2014/749317DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4009156PMC
May 2014

Effects of acute creatine supplementation on iron homeostasis and uric acid-based antioxidant capacity of plasma after wingate test.

J Int Soc Sports Nutr 2012 Jun 12;9(1):25. Epub 2012 Jun 12.

Department of Physical Education, Federal University of Parana, 80215-370, Curitiba, PR, Brazil.

Background: Dietary creatine has been largely used as an ergogenic aid to improve strength and athletic performance, especially in short-term and high energy-demanding anaerobic exercise. Recent findings have also suggested a possible antioxidant role for creatine in muscle tissues during exercise. Here we evaluate the effects of a 1-week regimen of 20 g/day creatine supplementation on the plasma antioxidant capacity, free and heme iron content, and uric acid and lipid peroxidation levels of young subjects (23.1 ± 5.8 years old) immediately before and 5 and 60 min after the exhaustive Wingate test.

Results: Maximum anaerobic power was improved by acute creatine supplementation (10.5 %), but it was accompanied by a 2.4-fold increase in pro-oxidant free iron ions in the plasma. However, potential iron-driven oxidative insult was adequately counterbalanced by proportional increases in antioxidant ferric-reducing activity in plasma (FRAP), leading to unaltered lipid peroxidation levels. Interestingly, the FRAP index, found to be highly dependent on uric acid levels in the placebo group, also had an additional contribution from other circulating metabolites in creatine-fed subjects.

Conclusions: Our data suggest that acute creatine supplementation improved the anaerobic performance of athletes and limited short-term oxidative insults, since creatine-induced iron overload was efficiently circumvented by acquired FRAP capacity attributed to: overproduction of uric acid in energy-depleted muscles (as an end-product of purine metabolism and a powerful iron chelating agent) and inherent antioxidant activity of creatine.
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http://dx.doi.org/10.1186/1550-2783-9-25DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3439332PMC
June 2012

Strength and hypertrophy responses to constant and decreasing rest intervals in trained men using creatine supplementation.

J Int Soc Sports Nutr 2011 Oct 27;8(1):17. Epub 2011 Oct 27.

Department of Physical Education, Federal University of Parana, Curitiba, Paraná, Brazil.

Background: The purpose of the current study was to compare strength and hypertrophy responses to resistance training programs that instituted constant rest intervals (CI) and decreasing rest intervals (DI) between sets over the course of eight weeks by trained men who supplemented with creatine monohydrate (CR).

Methods: Twenty-two recreationally trained men were randomly assigned to a CI group (n = 11; 22.3 ± 1 years; 77.7 ± 5.4 kg; 180 ± 2.2 cm) or a DI group (n = 11; 22 ± 2.5 years; 75.8 ± 4.9 kg; 178.8 ± 3.4 cm). Subjects in both groups supplemented with CR; the only difference between groups was the rest interval instituted between sets; the CI group used 2 minutes rest intervals between sets and exercises for the entire 8-weeks of training, while the DI group started with a 2 minute rest interval the first two weeks; after which the rest interval between sets was decreased 15 seconds per week (i.e. 2 minutes decreasing to 30 seconds between sets). Pre- and post-intervention maximal strength for the free weight back squat and bench press exercises and isokinetic peak torque were assessed for the knee extensors and flexors. Additionally, muscle cross-sectional area (CSA) of the right thigh and upper arm was measured using magnetic resonance imaging.

Results: Both groups demonstrated significant increases in back squat and bench press maximal strength, knee extensor and flexor isokinetic peak torque, and upper arm and right thigh CSA from pre- to post-training (p ≤ 0.0001); however, there were no significant differences between groups for any of these variables. The total volume for the bench press and back squat were significantly greater for CI group versus the DI group.

Conclusions: We report that the combination of CR supplementation and resistance training can increase muscular strength, isokinetic peak torque, and muscle CSA, irrespective of the rest interval length between sets. Because the volume of training was greater for the CI group versus the DI group, yet strength gains were similar, the creatine supplementation appeared to bolster adaptations for the DI group, even in the presence of significantly less volume. However, further research is needed with the inclusion of a control group not receiving supplementation combined and resistance training with decreasing rest intervals to further elucidate such hypotheses.
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http://dx.doi.org/10.1186/1550-2783-8-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3215636PMC
October 2011
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