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1.
The effects of varying doses of caffeine on cardiac parasympathetic reactivation following an acute bout of anaerobic exercise in recreational athletes.
Sarshin, A, Naderi, A, da Cruz, CJG, Feizolahi, F, Forbes, SC, Candow, DG, Mohammadgholian, E, Amiri, M, Jafari, N, Rahimi, A, et al
Journal of the International Society of Sports Nutrition. 2020;(1):44
Abstract
BACKGROUND To examine the effects of varying doses of caffeine on autonomic reactivation following anaerobic exercise. METHODS Recreationally active males (N = 20; 24 ± 2y) participated in a randomized, double-blind, placebo-controlled, crossover study where participants ingested: [1] Control (CON; no supplement), [2] a non-caffeinated placebo (PLA), [3] 3-mg∙kg- 1 of caffeine (CAF3) or [4] 6-mg∙kg- 1 of caffeine (CAF6) prior to Wingate testing. Parasympathetic (lnRMSSD, primary outcome) and global HRV (lnSDNN, secondary outcome) were assessed at rest (i.e., pre-ingestion), 45-min post-ingestion, and 5-min and 35-min post-exercise recovery. We used a GLM to assess mean (95% CI) changes from pre-ingestion baseline. RESULTS Overall, we observed a significant trend for lnRMSSD and lnSDNN (both, p = 0.001, ηp2 = 0.745). Forty-five minutes after treatment ingestion, we observed a significant increase in lnRMSSD for CAF3 (0.15 ms, 95%CI, 0.07,0.24) and CAF6 (0.16 ms, 95%CI, 0.06,0.25), both being significant (both, p < 0.004) vs. CON (- 0.02 ms, 95%CI, - 0.09,0.04). Five-minutes after exercise, all treatments demonstrated significant declines in lnRMSSD vs. baseline (all, p < 0.001). After 35-min of recovery, lnRMSSD returned to a level not significantly different than baseline for CAF3 (0.03 ms, 95%CI, - 0.05, 0.12) and CAF6 (- 0.03 ms, 95%CI, - 0.17, 0.10), while PLA (- 0.16 ms, 95%CI, - 0.25, - 0.06) and CON (- 0.17 ms, 95%CI, - 0.28, - 0.07) treatments remained significantly depressed. A similar pattern was also observed for SDNN. CONCLUSION Caffeine ingestion increases resting cardiac autonomic modulation and accelerates post-exercise autonomic recovery after a bout of anaerobic exercise in recreationally active young men. However, no differences between caffeine doses on cardiac autonomic reactivity were observed.
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2.
One Week of L-Citrulline Supplementation Improves Performance in Trained Cyclists.
Stanelle, ST, McLaughlin, KL, Crouse, SF
Journal of strength and conditioning research. 2020;(3):647-652
Abstract
Stanelle, ST, McLaughlin, KL, and Crouse, SF. One week of L-citrulline supplementation improves performance in trained cyclists. J Strength Cond Res 34(3): 647-652, 2020-L-citrulline (CIT) is a nonessential amino acid that is touted as an ergogenic aid for athletic performance because of its purported ability to stimulate nitric oxide production. Although previous research has demonstrated that CIT supplementation over a period of days improves physiological factors such as V[Combining Dot Above]O2 kinetics, no studies to date have explored whether there is a direct benefit to endurance performance. This study used a randomized, double-blind, crossover design to test whether chronic supplementation with pure CIT improves cycling performance over a maltodextrin placebo (PLAC). Nine trained male cyclists (24 ± 3 years; 181 ± 7 cm; 76 ± 13 kg; 4.18 ± 0.51 L·min V[Combining Dot Above]O2max) completed two 7-day supplementation periods (6 g·d of CIT or PLAC) separated by a 7-day washout. Subjects consumed the final 6-g dose 2 hours before the cycling performance evaluation, which consisted of a 40-km time trial (TT) followed by a supramaximal sprint repeat task (SRT). Paired t-tests and repeated-measures analysis of variance (α = 0.05) were used to analyze TT and SRT data, respectively. CIT supplementation produced an improvement in TT time of 5.2% that trended toward significance (p = 0.08). Furthermore, CIT promoted a significant increase in average heart rate, average rating of perceived exertion, and average power throughout the TT (p < 0.05). However, supplementation with CIT did not prevent fatigue during the SRT. Overall, this study is the first to demonstrate that CIT supplementation may provide a modest improvement to endurance cycling performance in trained athletes.
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3.
Is Coffee a Useful Source of Caffeine Preexercise?
Pickering, C, Grgic, J
International journal of sport nutrition and exercise metabolism. 2020;(1):69-82
Abstract
Caffeine is a well-established ergogenic aid, with its performance-enhancing effects demonstrated across a wide variety of exercise modalities. Athletes tend to frequently consume caffeine as a performance enhancement method in training and competition. There are a number of methods available as a means of consuming caffeine around exercise, including caffeine anhydrous, sports drinks, caffeine carbohydrate gels, and gum. One popular method of caffeine ingestion in nonathletes is coffee, with some evidence suggesting it is also utilized by athletes. In this article, we discuss the research pertaining to the use of coffee as an ergogenic aid, exploring (a) whether caffeinated coffee is ergogenic, (b) whether dose-matched caffeinated coffee provides a performance benefit similar in magnitude to caffeine anhydrous, and (c) whether decaffeinated coffee consumption affects the ergogenic effects of a subsequent isolated caffeine dose. There is limited evidence that caffeinated coffee has the potential to offer ergogenic effects similar in magnitude to caffeine anhydrous; however, this requires further investigation. Coingestion of caffeine with decaffeinated coffee does not seem to limit the ergogenic effects of caffeine. Although caffeinated coffee is potentially ergogenic, its use as a preexercise caffeine ingestion method represents some practical hurdles to athletes, including the consumption of large volumes of liquid and difficulties in quantifying the exact caffeine dose, as differences in coffee type and brewing method may alter caffeine content. The use of caffeinated coffee around exercise has the potential to enhance performance, but athletes and coaches should be mindful of the practical limitations.
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4.
Acute Effects of Beetroot Juice Supplements on Resistance Training: A Randomized Double-Blind Crossover.
Ranchal-Sanchez, A, Diaz-Bernier, VM, De La Florida-Villagran, CA, Llorente-Cantarero, FJ, Campos-Perez, J, Jurado-Castro, JM
Nutrients. 2020;(7)
Abstract
The ingestion of beetroot juice (BJ) has been associated with improvements in physical performance in endurance sports, however the literature on resistance training (RT) is scarce. The aim of this study was to investigate the acute effects of BJ compared to a placebo (PLA) on muscular endurance and movement concentric velocity during RT. Twelve healthy men performed an incremental RT test (back squat and bench press) with three sets, at 60%, 70%, and 80% of their repetition maximum (1-RM). Movement velocity variables, total number of repetitions performed until concentric failure, blood lactate, and ratings of perceived effort post-training were measured. A higher number of repetitions were recorded with BJ compared to those with PLA (13.8 ± 14.4; p < 0.01; effect size (ES) = 0.6). Differences were found at 60% 1-RM (9 ± 10; p < 0.05; ES = 0.61) and 70% 1-RM (3.1 ± 4.8; p < 0.05; ES = 0.49), however, no differences were found at 80% 1-RM (1.7 ± 1; p = 0.12; ES = 0.41). A greater number of repetitions was performed in back squat (13.4 ± 13; p < 0.01; ES = 0.77), but no differences were observed in bench press (0.4 ± 5.1; p = 0.785; ES = 0.03). No differences were found for the rest of the variables (p > 0.05). Acute supplementation of BJ improved muscular endurance performance in RT.
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5.
Influence of Nitrate Supplementation on Endurance Cyclic Sports Performance: A Systematic Review.
Lorenzo Calvo, J, Alorda-Capo, F, Pareja-Galeano, H, Jiménez, SL
Nutrients. 2020;(6)
Abstract
Endurance can be defined as the capacity to maintain one's velocity or power output for the longest possible time. Maintaining such activity can lead to the onset of fatigue. Dietary nitrate supplementation produces an ergogenic effect due to the improvement of mitochondrial oxygen efficiency through a reduction in the oxygen cost of exercise that increases vasodilation and blood flow to the skeletal muscle in recreationally active subjects. However, the effects of dietary nitrate supplementation on well-trained endurance athletes remain unclear; such supplementation could affect more performance areas. In the present study, a systematic review of the literature was conducted to clarify the use and effects of nitrate as a dietary supplement in endurance athletes trained in cyclic sports (repetitive movement sports). A systematic search was carried out following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in the databases of SCOPUS, Web of Science (WOS), Medline (PubMed), and Sport Discus from 1 January 2010 to 30 November 2019. Twenty-seven studies were included in the study. The methodological quality of the articles was assessed using the McMaster Critical Review Form. Statistically significant ergogenic results were obtained in 8 (29.63%) of the 27 studies investigated, with significant results obtained for cardiorespiratory parameters and performance measures. Improvement in exercise tolerance was obtained, which could help with exhaustion over time, while the improvement in exercise economics was not as clear. Additionally, the dose necessary for this ergogenic effect seems to have a direct relationship with the physical condition of the athlete. The acute dose is around 6-12.4 mmol/day of nitrate administered 2-3 h before the activity, with the same amount given as a chronic dose over 6-15 days. Further studies are required to understand the factors that affect the potential ergogenic impacts of nitrate on athletic performance among endurance athletes.
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6.
Health Behaviors and Psychosocial Attributes of US Soldiers.
Kegel, JL, Kazman, JB, Scott, JM, Deuster, PA
Journal of the Academy of Nutrition and Dietetics. 2020;(9):1469-1483
Abstract
BACKGROUND Health trends, which promote performance enhancement and maintaining or increasing muscle strength, may appeal to soldiers looking to maintain health standards set by the US Army, but often these trends require further investigation to assess safety and efficacy. High-intensity interval training (HIIT) and use of weight loss and/or performance-enhancing/body-building dietary supplements (WL/PES DS) are two such trends that, if implemented inappropriately, can negatively impact soldier health and readiness. OBJECTIVE Our aim was to establish health/psychosocial profiles of US Army soldiers who participate in HIIT and/or use WL/PES DS. DESIGN This cross-sectional observational study used data from the 2016 US Army Global Assessment Tool. PARTICIPANTS Data were analyzed from respondents to the 2016 US Army Global Assessment Tool (n=299,996) who consented to have their data used for research purposes. RESULTS Soldiers were classified into four groups based on HIIT and/or WL/PES DS use. Thirty-five percent of soldiers participated in HIIT and 10% took WL/PES DS at least once per month in the last year. HIIT participation was associated with higher reported odds of healthy behaviors and higher emotional and social fitness. In contrast to HIIT, WL/PES DS use was associated with higher reported odds of risky behaviors (hazardous drinking and tobacco use) and lower psychosocial fitness. The group participating in HIIT but not using WL/PES DS reported fewer unhealthy behaviors compared to the HIIT+WL/PES DS and WL/PES DS-only groups. CONCLUSIONS Engaging in HIIT is associated with higher reported odds of healthy behaviors and increased psychosocial fitness. However, soldiers who engaged in HIIT also have increased odds of WL/PES DS use, which is associated with greater reported risky behaviors and reduced fitness. Although HIIT and WL/PES DS use are related, they are associated with different reported health/risky behaviors and different psychosocial attributes.
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7.
Combined protein and calcium β-hydroxy-β-methylbutyrate induced gains in leg fat free mass: a double-blinded, placebo-controlled study.
Stahn, AC, Maggioni, MA, Gunga, HC, Terblanche, E
Journal of the International Society of Sports Nutrition. 2020;(1):16
Abstract
BACKGROUND The leucine metabolite β-hydroxy-β-methylbutyrate (HMB) is widely used as an ergogenic supplement to increase resistance-training induced gains in fat free mass (FFM) and strength in healthy adults. Recent studies have questioned the effectiveness of HMB, particularly when a high protein diet is habitually consumed. To investigate the additive resistance-training induced effects of HMB and protein in untrained individuals, we conducted a randomized double-blind, placebo-controlled study that compared the effects of combined protein and HMB supplementation to protein supplementation alone on FFM and muscle strength after 12-week resistance training. METHODS Sixteen healthy men (22 ± 2 yrs) performed a periodized resistance-training program for twelve weeks (four sessions per week). The program comprised two mesocycles, characterized by a linear periodization and non-linear periodization, respectively, and separated by a 1-week tapering period. All participants received 60 g of whey protein on training days and 30 g of whey protein (WP) on non-training days. Participants were randomly assigned to additionally receive 3 g of calcium HMB (WP + HMB) or a placebo (WP + PLA). Body composition and physical fitness were tested before and after the 12-week training program. Whole-body and arm and leg fat free mass (FFM) were assessed by bioimpedance spectroscopy; upper arm and leg fat free cross sectional areas were also quantified using magnetic resonance imaging (MRI); upper and lower body strength were measured by One-repetition maximum (1-RM) bench press and leg press. RESULTS Whole-body and segmental FFM increased in both groups (P < 0.001). However, gains in leg FFM were higher in WP + HMB vs. WP + PLA (arm FFM: + 6.1% vs. + 9.2%, P = 0.2; leg FFM: + 14.2% vs. + 7.0%, P < 0.01). No change in fat mass was observed (P = 0.59). 1-RM increased in both groups (P < 0.001). CONCLUSIONS Combined protein and HMB supplementation resulted in segmental, but not whole-body increases in FFM compared to protein supplementation alone. These findings could explain some of the controversial effects of HMB reported in previous studies and have practical implications for maximizing training-induced gains in FFM and clinical conditions associated with skeletal muscle deconditioning such as aging, sedentary lifestyles, bed rest and spaceflight.
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8.
Effects of caffeine supplementation on physical performance and mood dimensions in elite and trained-recreational athletes.
Jodra, P, Lago-Rodríguez, A, Sánchez-Oliver, AJ, López-Samanes, A, Pérez-López, A, Veiga-Herreros, P, San Juan, AF, Domínguez, R
Journal of the International Society of Sports Nutrition. 2020;(1):2
Abstract
BACKGROUND Caffeine supplementation (CAFF) has an established ergogenic effect on physical performance and the psychological response to exercise. However, few studies have compared the response to CAFF intake among athletes of different competition level. This study compares the acute effects of CAFF on anaerobic performance, mood and perceived effort in elite and moderately-trained recreational athletes. METHODS Participants for this randomized, controlled, crossover study were 8 elite athletes (in the senior boxing national team) and 10 trained-recreational athletes. Under two experimental conditions, CAFF supplementation (6 mg/kg) or placebo (PLAC), the athletes completed a Wingate test. Subjective exertion during the test was recorded as the rating of perceived exertion (RPE) both at the general level (RPEgeneral) and at the levels muscular (RPEmuscular) and cardiorespiratory (RPEcardio). Before the Wingate test, participants completed the questionnaires Profiles of Moods States (POMS) and Subjective Vitality Scale (SVS). RESULTS In response to CAFF intake, improvements were noted in Wpeak (11.22 ± 0.65 vs 10.70 ± 0.84; p = 0.003; [Formula: see text] =0.44), Wavg (8.75 ± 0.55 vs 8.41 0.46; p = 0.001; [Formula: see text] =0.53) and time taken to reach Wpeak (7.56 ± 1.58 vs 9.11 ± 1.53; p < 0.001; [Formula: see text] =0.57) both in the elite and trained-recreational athletes. However, only the elite athletes showed significant increases in tension (+ 325%), vigor (+ 31%) and SVS (+ 28%) scores after the intake of CAFF compared to levels recorded under the condition PLAC (p < 0.05). Similarly, levels of vigor after consuming CAFF were significantly higher in the elite than the trained-recreational athletes (+ 5.8%). CONCLUSIONS CAFF supplementation improved anaerobic performance in both the elite and recreational athletes. However, the ergogenic effect of CAFF on several mood dimensions and subjective vitality was greater in the elite athletes.
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9.
ADOR2A C Allele Carriers Exhibit Ergogenic Responses to Caffeine Supplementation.
Grgic, J, Pickering, C, Bishop, DJ, Del Coso, J, Schoenfeld, BJ, Tinsley, GM, Pedisic, Z
Nutrients. 2020;(3)
Abstract
Caffeine's ergogenic effects on exercise performance are generally explained by its ability to bind to adenosine receptors. ADORA2A is the gene that encodes A2A subtypes of adenosine receptors. It has been suggested that ADORA2A gene polymorphisms may be responsible for the inter-individual variations in the effects of caffeine on exercise performance. In the only study that explored the influence of variation in ADORA2A-in this case, a common polymorphism (rs5751876)-on the ergogenic effects of caffeine on exercise performance, C allele carriers were identified as "non-responders" to caffeine. To explore if C allele carriers are true "non-responders" to the ergogenic effects of caffeine, in this randomized, double-blind study, we examined the acute effects of caffeine ingestion among a sample consisting exclusively of ADORA2A C allele carriers. Twenty resistance-trained men identified as ADORA2A C allele carriers (CC/CT genotype) were tested on two occasions, following the ingestion of caffeine (3 mg/kg) and a placebo. Exercise performance was evaluated with movement velocity, power output, and muscle endurance during the bench press exercise, countermovement jump height, and power output during a Wingate test. Out of the 25 analyzed variables, caffeine was ergogenic in 21 (effect size range: 0.14 to 0.96). In conclusion, ADORA2A (rs5751876) C allele carriers exhibited ergogenic responses to caffeine ingestion, with the magnitude of improvements similar to what was previously reported in the literature among samples that were not genotype-specific. Therefore, individuals with the CT/CC genotype may still consider supplementing with caffeine for acute improvements in performance.
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10.
High dose Nitrate ingestion does not improve 40 km cycling time trial performance in trained cyclists.
Mosher, SL, Gough, LA, Deb, S, Saunders, B, Mc Naughton, LR, Brown, DR, Sparks, SA
Research in sports medicine (Print). 2020;(1):138-146
Abstract
This study evaluated the chronic effects of nitrate (NO3-) ingestion over three days, on 40 km TT performance in 11trained cyclists (VO2max: 60.8 ± 7.4 ml.kg-1.min-1; age: 36 ± 9 years; height: 1.80 ± 0.06 m; body mass: 87.2 ± 12.0 kg). Utilising a double-blind randomised cross-over design, participants completed three 40 km TT on a Velotron® ergometer following the ingestion of either a 140 ml of "BEET It sport®" NO3- shot containing 12.8 mmol or 800 mg of NO3-, a placebo drink or nothing (control). Performance, oxygen consumption (VO2), blood bicarbonate (HCO3-), pH and lactate (BLa) and ratings of perceived exertion (RPE) were measured every 10 km throughout the TT. The present findings show that NO3- ingestion had no effect on TT performance (NO3-: 4098.0 ± 209.8 vs. Placebo: 4161.9 ± 263.3 s, p = 0.296, ES = 0.11), or VO2 (p = 0.253, ES = 0.13). Similarly, blood lactate and RPE were also unaffected by the experimental conditions (p = 0.522, ES = 0.06; p = 0.085, ES = 0.30) respectively. Therefore, these results suggest that a high dose of NO3- over three days has limited efficacy as an ergogenic aid for 40 km TT cycling performance in trained cyclists.