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1.
Branched-chain amino acid supplementation improves cycling performance in untrained cyclists.
Manaf, FA, Peiffer, JJ, Maker, GL, Fairchild, TJ
Journal of science and medicine in sport. 2021;(4):412-417
Abstract
OBJECTIVES To investigate the effects of acute branched-chain amino acid (BCAA) supplementation on cycling performance and neuromuscular fatigue during a prolonged, self-paced cycling time-trial. DESIGN Randomised double-blind counterbalanced crossover. METHODS Eighteen recreationally active men (mean±SD; age: 24.7±4.8 years old; body-weight, BW: 67.1±6.1kg; height: 171.7±4.9cm) performed a cycling time-trial on an electromagnetically-braked cycle ergometer. Participants were instructed to complete the individualised total work in the shortest time possible, while ingesting either BCAAs (pre-exercise: 0.084gkg-1 BW; during exercise: 0.056gkg-1h-1) or a non-caloric placebo solution. Rating of perceived exertion, power, cadence and heart rate were recorded throughout, while maximal voluntary contraction, muscle voluntary activation level and electrically evoked torque using single and doublet stimulations were assessed at baseline, immediately post-exercise and 20-min post-exercise. RESULTS Supplementation with BCAA reduced (287.9±549.7s; p=0.04) time-to-completion and ratings of perceived exertion (p≤0.01), while concomitantly increasing heart rate (p=0.02). There were no between-group differences (BCAA vs placebo) in any of the neuromuscular parameters, but significant decreases (All p≤0.01) in maximal voluntary contraction, muscle voluntary activation level and electrically evoked torque (single and doublet stimulations) were recorded immediately following the trial, and these did not recover to pre-exercise values by the 20min recovery time-point. CONCLUSIONS Compared to a non-caloric placebo, acute BCAA supplementation significantly improved performance in cycling time-trial among recreationally active individuals without any notable changes in either central or peripheral factors. This improved performance with acute BCAA supplementation was associated with a reduced rating of perceived exertion.
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2.
Effect of citrulline on post-exercise rating of perceived exertion, muscle soreness, and blood lactate levels: A systematic review and meta-analysis.
Rhim, HC, Kim, SJ, Park, J, Jang, KM
Journal of sport and health science. 2020;(6):553-561
Abstract
BACKGROUND Citrulline is one of the non-essential amino acids that is thought to improve exercise performance and reduce post-exercise muscle soreness. We conducted a systematic review and meta-analysis to determine the effect of citrulline supplements on the post-exercise rating of perceived exertion (RPE), muscle soreness, and blood lactate levels. METHODS A random effects model was used to calculate the effect sizes due to the high variability in the study design and study populations of the articles included. A systematic search of PubMed, Web of Science, and ClinicalTrials.gov was performed. Eligibility for study inclusion was limited to studies that were randomized controlled trials involving healthy individuals and that investigated the acute effect of citrulline supplements on RPE, muscle soreness, and blood lactate levels. The supplementation time frame was limited to 2 h before exercise. The types and number of participants, types of exercise tests performed, supplementation protocols for L-citrulline or citrulline malate, and primary (RPE and muscle soreness) and secondary (blood lactate level) study outcomes were extracted from the identified studies. RESULTS The analysis included 13 eligible articles including a total of 206 participants. The most frequent dosage used in the studies was 8 g of citrulline malate. Citrulline supplementation significantly reduced RPE (n = 7, p = 0.03) and muscle soreness 24-h and 48-h after post-exercise (n = 7, p = 0.04; n = 6, p = 0.25, respectively). However, citrulline supplementation did not significantly reduce muscle soreness 72-h post-exercise (n = 4, p = 0.62) or lower blood lactate levels (n = 8, p = 0.17). CONCLUSION Citrulline supplements significantly reduced post-exercise RPE and muscle soreness without affecting blood lactate levels.
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3.
Does rest interval between sets affect resistance training volume, density, and rating of perceived exertion when adopting the crescent pyramid system in young women?
Kassiano, W, Medeiros, AI, de Vasconcelos Costa, BD, Andrade, AD, Moura Simim, MA, de Sousa Fortes, L, Cyrino, ES, de Oliveira Assumpção, C
The Journal of sports medicine and physical fitness. 2020;(7):992-998
Abstract
BACKGROUND The rest interval between sets can affect the responses to resistance training. Thus, the purpose of this study was to compare the effects of different rest intervals (RI) on volume, density, and rating of perceived exertion (RPE) when adopting a crescent pyramid (CP) system. METHODS Twenty young women (21.1±2.6 years, 1.59±0.06 m, 58.5±9.3 kg) participated in this study. All participants performed three experimental sessions of the leg press exercise in 5 sets until voluntary muscular failure at 60%, 65%, 70%, 75%, and 80% of one-repetition maximum (1RM). A randomized and crossover design was used so that in each session one of three RI (RI-1 = 1 min, RI-2 = 2 min, and RI-3 = 3 min) was tested. RESULTS The participants performed a significantly larger volume in the RI-3 (12820±3134 kg) when compared to RI-1 (10367±3053 kg) condition (P<0.05). The volume did not differ between RI-2 and RI-3 (P>0.05). The density was higher (P<0.05) in RI-1 (43.1±12.7 kg/s) when compared RI-2 (25.6±5.8 kg/s) and RI-3 (17.7±4.3 kg/s). The RI-2 presented higher density compared to RI-3 condition (P<0.05). The RPE was not different between the three conditions (P>0.05). CONCLUSIONS The use of 2 minutes of rest between sets allowed the performance of a high volume-load and density of the session in young women. In addition, the three experimental sessions provided a high perception of effort.
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4.
Effect of Beetroot Juice Supplementation on Mood, Perceived Exertion, and Performance During a 30-Second Wingate Test.
Jodra, P, Domínguez, R, Sánchez-Oliver, AJ, Veiga-Herreros, P, Bailey, SJ
International journal of sports physiology and performance. 2020;(2):243-248
Abstract
PURPOSE Dietary supplementation with inorganic nitrate (NO3-) can enhance high-intensity exercise performance by improving skeletal muscle contractility and metabolism, but the extent to which this might be linked to altered psychophysiological processes is presently unclear. The purpose of this study was to assess the effects of NO3--rich beetroot juice (BJ) supplementation on profile of mood states, ratings of perceived exertion (RPE), and performance in a 30-second Wingate cycle test. METHODS In a double-blind, randomized, cross-over study, 15 subjects completed 2 laboratory sessions after ingesting NO3--rich or NO3--depleted (placebo) BJ. Participants initially completed the profile of mood states questionnaire. Subsequently, participants completed a warm-up followed by a 30-second all-out Wingate cycling test. After the Wingate test, participants immediately indicated the RPE of their leg muscles (RPEmuscular), cardiovascular system (RPEcardio), and general RPE (RPEgeneral). RESULTS Compared with the placebo condition, supplementation with BJ increased peak power output (Wpeak) (+4.4%, 11.5 [0.7] vs 11.1 [1.0] W·kg-1; P = .039) and lowered the time taken to reach Wpeak (7.3 [0.9] vs 8.7 [1.5] s; P = .002) during the Wingate test. The profile of mood states score linked to tension was increased prior to the Wingate test (4.8 [3.0] vs 3.4 [2.4]; P = .040), and RPEmuscular was lowered immediately following the Wingate test (17.7 [1.6] vs 18.3 [1.0]; P = .031), after BJ compared with placebo ingestion. CONCLUSIONS Acute BJ supplementation improved pre-exercise tension, 30-second Wingate test performance, and lowered postexercise RPEmuscular.
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5.
The beneficial effects of a water-based aerobic exercise session on the blood lipids of women with dyslipidemia are independent of their training status.
Costa, RR, Buttelli, ACK, Fagundes, AO, Fonseca, GA, Pilla, C, Barreto, MF, Viero, PA, Rocha, VMBD, Alberton, CL, Kruel, LFM
Clinics (Sao Paulo, Brazil). 2020;:e1183
Abstract
OBJECTIVES To evaluate the acute effects of a session of water-based aerobic exercise on the blood lipid levels of women with dyslipidemia and to compare these results according to their training status. METHOD Fourteen premenopausal women with dyslipidemia, aged 40-50 years, participated in two water-based aerobic exercise sessions, the first when they were generally sedentary and the second after they were trained with a water-based aerobic training program for 12 weeks. Both experimental sessions were performed using the same protocol, lasted 45 min, and incorporated an interval method, alternating 3 min at a rating of perceived exertion (RPE) of 13 and 2 min at an RPE of 9. Total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and lipoprotein lipase enzyme (LPL) were obtained through venous blood collection before and immediately after each session. A generalized estimating equation method and Bonferroni tests were conducted (with time and training status as factors) for statistical analyses. RESULTS At enrollment, the mean age of the participants was 46.57 years (95% confidence interval [CI] 44.81-48.34). The statistical analyses showed a significant time effect for all variables (TC: p=0.008; TG: p=0.012; HDL: p<0.001; LPL: p<0.001) except for LDL (p=0.307). However, the training status effect was not significant for any variable (TC: p=0.527; TG: p=0.899; HDL: p=0.938; LDL: p=0.522; LPL: p=0.737). These results indicate that the TC and TG levels reduced and the HDL and LPL concentrations increased from pre- to post-session in similar magnitudes in both sedentary and trained women. CONCLUSIONS A single water-based aerobic exercise session is sufficient and effective to beneficially modify the lipid profile of women with dyslipidemia, regardless of their training status.
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6.
Effect of caffeine supplementation on exercise performance, power, markers of muscle damage, and perceived exertion in trained CrossFit men: a randomized, double-blind, placebo-controlled crossover trial.
Fogaça, LJ, Santos, SL, Soares, RC, Gentil, P, Naves, JP, Dos Santos, WD, Pimentel, GD, Bottaro, M, Mota, JF
The Journal of sports medicine and physical fitness. 2020;(2):181-188
Abstract
BACKGROUND Caffeine is a popular nutritional supplement among athletes. It is frequently used as an ergogenic aid to improve physical performance, delay fatigue, and increase muscle power. However, these effects have not been tested in CrossFit athletes. The aim of this study was to evaluate the effects of acute caffeine supplementation on workout performance, power, markers of muscle damage, and soreness in trained CrossFit men. METHODS Nine men (28±2 years) with experience in CrossFit (2±0.3 years) were investigated in a randomized, double-blind, placebo-controlled crossover trial, with a 7-day washout between treatment periods. The athletes received anhydrous caffeine (CAF: 6 mg/kg body mass) or placebo (PLA) 60 minutes before a CrossFit workout with tasks that involved muscle strength, power, gymnastic movements, and metabolic conditioning. Blood samples were collected for creatine kinase (CK), C-reactive protein, and glucose determination. Workout performance, rating of perceived exertion (RPE), delayed-onset muscle soreness (DOMS), muscle strength (handgrip strength) and power (bench throw, jump squat and countermovement jump) were also evaluated. RESULTS CAF resulted in higher glucose concentration after workout compared to PLA (+3.2 mmol/L, 95% CI: 2.1 to 4.3 vs. +1.5, 95% CI: -0.1 to 3.0 mmol/L, P=0.01). No differences were found between treatments in workout performance, CK, DOMS, RPE, muscle power and strength. CONCLUSIONS Acute CAF supplementation did not alter performance, markers of muscle damage, power, and RPE in trained CrossFit men.
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7.
Carbohydrate and Glutamine Supplementation Attenuates the Increase in Rating of Perceived Exertion during Intense Exercise in Hypoxia Similar to 4200 m.
Caris, AV, Thomatieli-Santos, RV
Nutrients. 2020;(12)
Abstract
The rating of perceived exertion (RPE) indicates the feeling of fatigue. However, hypoxia worsens the condition and can worsen RPE. We evaluated whether carbohydrate and glutamine supplementation alters RPE and physiological markers in running at 70% peak oxygen uptake until exhaustion in a simulated altitude of 4500 m. Nine volunteers underwent three running tests at 70% peak oxygen uptake until exhaustion: (1) hypoxia and placebo, (2) hypoxia and 8% maltodextrin, and (3) hypoxia after six days of glutamine supplementation (20 g/day) and 8% maltodextrin. The exercise and supplementation were randomized and double-blinded. Lactate, heart rate, haemoglobin O2 saturation (SpO2%), and RPE (6-20 scale) were analyzed at the 15th and 30th min. The level of significance was set at p ≤ 0.05. SpO2% decreased at the 15th and 30th minutes compared to resting in placebo, carbohydrate, and glutamine supplementation. RPE increased at the 30th minute compared to the 15th minute in placebo and carbohydrate supplementation; however, there was no difference in the glutamine supplementation condition. Heart rate and lactate increased after the 15th and 30th minutes compared to resting, similar to the three conditions studied. We conclude that previous supplementation with glutamine and carbohydrate during intense exercise in hypoxia similar to 4500 m can attenuate the increase in RPE by the increase in glycemia and can be a useful strategy for people who exercise in these conditions.
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8.
Effects of a Ketogenic Diet on Muscle Fatigue in Healthy, Young, Normal-Weight Women: A Randomized Controlled Feeding Trial.
Sjödin, A, Hellström, F, Sehlstedt, E, Svensson, M, Burén, J
Nutrients. 2020;(4)
Abstract
Ketogenic low-carbohydrate high-fat (LCHF) diets are increasingly popular in broad sections of the population. The main objective of this study was to evaluate the effects of a non-energy-restricted ketogenic LCHF diet on muscle fatigue in healthy, young, and normal-weight women. Twenty-four women were randomly allocated to a 4-week ketogenic LCHF diet followed by a 4-week control diet (a National Food Agency recommended diet), or the reverse sequence due to the crossover design. Treatment periods were separated by a 15 week washout period. Seventeen women completed the study and were included in the analyses. Treatment effects were evaluated using mixed models. The ketogenic LCHF diet had no effect on grip strength or time to fatigue, measured with handgrip test (day 24-26). However, cycling time to fatigue decreased with almost two minutes (-1.85 min 95% CI:[-2.30;-1.40]; p < 0.001) during incremental cycling (day 25-27), accommodated with higher ratings of perceived exertion using the Borg scale (p < 0.01). Participants' own diary notes revealed experiences of muscle fatigue during daily life activities, as well as during exercise. We conclude that in young and healthy women, a ketogenic LCHF diet has an unfavorable effect on muscle fatigue and might affect perceived exertion during daily life activities.
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9.
Creatine supplementation can improve impact control in high-intensity interval training.
da Silva Azevedo, AP, Michelone Acquesta, F, Lancha, AH, Bertuzzi, R, Poortmans, JR, Amadio, AC, Cerca Serrão, J
Nutrition (Burbank, Los Angeles County, Calif.). 2019;:99-104
Abstract
OBJECTIVES This study aimed to investigate the effects of creatine (Cr) supplementation on biomechanical parameters related to shock attenuation during a session of high-intensity interval training (HIIT). METHODS A single-blinded, placebo-controlled, crossover design was adopted to test eight male elite soccer players during HIIT sessions under two conditions: after placebo supplementation and after Cr supplementation. HIIT test sessions consisted of an intermittent test (five bouts of running) with a constant load applied until exhaustion was reached. The vertical component of ground reaction force and electromyography data were recorded by Gaitway and Lynx-EMG Systems, respectively. Heart rate, rated perceived exertion (Borg's Scale) and lactate concentration information were also obtained. RESULTS Cr supplementation did not affect heart rate, rated perceived exertion, and lactate concentration. Decreased values of magnitude of the first peak of the vertical component of ground reaction force (17.2-24.2%) and impulse of the first 50 ms (Imp50; 34.3%) were observed for Cr, but higher values of time to reach the first peak were detected for Cr compared with placebo. Significant modifications in muscle activation were also observed, mainly in the pre-activation phase, and changes were observed in intermediary bouts. CONCLUSIONS Cr supplementation has the potential to influence biomechanical parameters related to impact control during a single session of HIIT based on running. In particular, the findings of the current study indicate possible improvements in shock attenuation and a safer practice of HIIT under Cr supplementation.
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10.
High-intensity interval exercise lowers postprandial glucose concentrations more in obese adults than lean adults.
Kong, Z, Shi, Q, Sun, S, Tong, TK, Zhang, H, Nie, J
Primary care diabetes. 2019;(6):568-573
Abstract
AIMS: To compare postprandial glucose responses to high-intensity interval exercise (HIE) between obese and lean individuals. METHODS Thirty healthy young adult males (15 obese, 15 lean) ate a standardised meal, then performed HIE (4 × 30-s Wingate cycling/4-min rest) or a no-exercise control trial (CON). Blood glucose was measured preprandially and up to 150 min postprandially. RESULTS Compared to CON, HIE reduced postprandial glucose concentrations at 120-150 min in obese (p < 0.001) and lean men (p < 0.05), with greater reductions in obese than lean subjects at 120 (-27.0% vs. -8.3%), 135 (-31.9% vs. -15.7%), and 150 min (-21.8% vs. -10.6%). The total glucose area under the curve (AUC) for the testing period was lower with HIE than CON among obese men (p < 0.05), but not lean men (p > 0.05). We found moderate correlations between body mass and postprandial glucose changes (r = 0.39-0.44, p < 0.05), and between glucose AUC and body mass and fat free mass (r = 0.39-0.48, p < 0.05). CONCLUSIONS Our findings suggest that HIE may act as a time-efficient lifestyle intervention strategy for improving obesity-related diabetes risk factors, and might play a role in primary diabetes prevention for the healthy but sedentary population.