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High Prevalence of Cannabidiol Use Within Male Professional Rugby Union and League Players: A Quest for Pain Relief and Enhanced Recovery

Andreas M. Kasper, S. Andy Sparks, Matthew Hooks, Matthew Skeer, Benjamin Webb, Houman Nia, James P. Morton, and Graeme L. Close

Rugby is characterized by frequent high-intensity collisions, resulting in muscle soreness. Players consequently seek strategies to reduce soreness and accelerate recovery, with an emerging method being cannabidiol (CBD), despite anti-doping risks. The prevalence and rationale for CBD use in rugby has not been explored; therefore, we recruited professional male players to complete a survey on CBD. Goodness of fit chi-square (χ2) was used to assess CBD use between codes and player position. Effects of age on use were determined using χ2 tests of independence. Twenty-five teams provided 517 player responses. While the majority of players had never used CBD (p < .001, V = 0.24), 26% had either used it (18%) or were still using it (8%). Significantly more CBD use was observed in rugby union compared with rugby league (p = .004, V = 0.13), but player position was not a factor (p = .760, V = 0.013). CBD use increased with players’ age (p < .001, V = 0.28), with mean use reaching 41% in the players aged 28 years and older category (p < .0001). The players using CBD primarily used the Internet (73%) or another teammate (61%) to obtain information, with only 16% consulting a nutritionist. The main reasons for CBD use were improving recovery/pain (80%) and sleep (78%), with 68% of players reporting a perceived benefit. These data highlight the need for immediate education on the risks of CBD, as well as the need to explore the claims regarding pain and sleep.

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A Tool to Explore Discrete-Time Data: The Time Series Response Analyser

Benjamin J. Narang, Greg Atkinson, Javier T. Gonzalez, and James A. Betts

The analysis of time series data is common in nutrition and metabolism research for quantifying the physiological responses to various stimuli. The reduction of many data from a time series into a summary statistic(s) can help quantify and communicate the overall response in a more straightforward way and in line with a specific hypothesis. Nevertheless, many summary statistics have been selected by various researchers, and some approaches are still complex. The time-intensive nature of such calculations can be a burden for especially large data sets and may, therefore, introduce computational errors, which are difficult to recognize and correct. In this short commentary, the authors introduce a newly developed tool that automates many of the processes commonly used by researchers for discrete time series analysis, with particular emphasis on how the tool may be implemented within nutrition and exercise science research.

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Carbohydrate Hydrogel Products Do Not Improve Performance or Gastrointestinal Distress During Moderate-Intensity Endurance Exercise

Andy J. King, Joshua T. Rowe, and Louise M. Burke

The benefits of ingesting exogenous carbohydrate (CHO) during prolonged exercise performance are well established. A recent food technology innovation has seen sodium alginate and pectin included in solutions of multiple transportable CHO, to encapsulate them at pH levels found in the stomach. Marketing claims include enhanced gastric emptying and delivery of CHO to the muscle with less gastrointestinal distress, leading to better sports performance. Emerging literature around such claims was identified by searching electronic databases; inclusion criteria were randomized controlled trials investigating metabolic and/or exercise performance parameters during endurance exercise >1 hr, with CHO hydrogels versus traditional CHO fluids and/or noncaloric hydrogels. Limitations associated with the heterogeneity of exercise protocols and control comparisons are noted. To date, improvements in exercise performance/capacity have not been clearly demonstrated with ingestion of CHO hydrogels above traditional CHO fluids. Studies utilizing isotopic tracers demonstrate similar rates of exogenous CHO oxidation, and subjective ratings of gastrointestinal distress do not appear to be different. Overall, data do not support any metabolic or performance advantages to exogenous CHO delivery in hydrogel form over traditional CHO preparations; although, one study demonstrates a possible glycogen sparing effect. The authors note that the current literature has largely failed to investigate the conditions under which maximal CHO availability is needed; high-performance athletes undertaking prolonged events at high relative and absolute exercise intensities. Although investigations are needed to better target the testimonials provided about CHO hydrogels, current evidence suggests that they are similar in outcome and a benefit to traditional CHO sources.

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Prevalence and Determinants of Fasted Training in Endurance Athletes: A Survey Analysis

Jeffrey A. Rothschild, Andrew E. Kilding, and Daniel J. Plews

Athletes may choose to perform exercise in the overnight-fasted state for a variety of reasons related to convenience, gut comfort, or augmenting the training response, but it is unclear how many endurance athletes use this strategy. We investigated the prevalence and determinants of exercise performed in the overnight-fasted state among endurance athletes using an online survey and examined differences based on sex, competitive level, and habitual dietary pattern. The survey was completed by 1,950 endurance athletes (51.0% female, mean age 40.9 ± 11.1 years). The use of fasted training was reported by 62.9% of athletes, with significant effects of sex (p < .001, Cramer’s Vc] = 0.18, 90% CI [0.14, 0.22]), competitive level (p < .001, φc = 0.09, 90% CI [0.5, 0.13]), and habitual dietary pattern noted (p < .001, φc = 0.26, 90% CI [0.22, 0.29]). Males, nonprofessional athletes, and athletes following a low-carbohydrate, high-fat diet were most likely to perform fasted training. The most common reasons for doing so were related to utilizing fat as a fuel source (42.9%), gut comfort (35.5%), and time constraints/convenience (31.4%), whereas the most common reasons athletes avoided fasted training were that it does not help their training (47.0%), performance was worse during fasted training (34.7%), or greater hunger (34.6%). Overall, some athletes perform fasted training because they think it helps their training, whereas others avoid it because they think it is detrimental to their training goals, highlighting a need for future research. These findings offer insights into the beliefs and practices related to fasted-state endurance training.

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The Effects of a High-Protein Diet on Markers of Muscle Damage Following Exercise in Active Older Adults: A Randomized, Controlled Trial

Tom Clifford, Eleanor J. Hayes, Jadine H. Scragg, Guy Taylor, Kieran Smith, Kelly A. Bowden Davies, and Emma J. Stevenson

Purpose: This study examined whether a higher protein diet following strenuous exercise can alter markers of muscle damage and inflammation in older adults. Methods: Using a double-blind, independent group design, 10 males and eight females (age 57 ± 4 years; mass 72.3 ± 5.6 kg; height 1.7 ± 6.5 m) were supplied with a higher protein (2.50 g·kg−1·day−1) or moderate protein (1.25 g·kg−1·day−1) diet for 48 hr after 140 squats with 25% of their body mass. Maximal isometric voluntary contractions, muscle soreness, creatine kinase, Brief Assessment of Mood Adapted, and inflammatory markers were measured preexercise, and 24 hr and 48 hr postexercise. Results: The maximal isometric voluntary contractions decreased postexercise (p = .001, η p 2 = .421 ), but did not differ between groups (p = .822, η p 2 = .012 ). Muscle soreness peaked at 24 hr post in moderate protein (44 ± 30 mm) and 48 hr post in higher protein (70 ± 46 mm; p = .005; η p 2 = .282 ); however, no group differences were found (p = .585; η p 2 = .083 ). Monocytes and lymphocytes significantly decreased postexercise, and eosinophils increased 24 hr postexercise (p < 0.05), but neutrophils, creatine kinase, interleukin-6, C-reactive protein, monocyte chemotactic protein-1, and Brief Assessment of Mood Adapted were unchanged by exercise or the intervention (p > .05). Conclusion: In conclusion, 2.50 g·kg−1·day−1 of protein is not more effective than 1.25 g·kg−1·day−1 for attenuating indirect markers of muscle damage and inflammation following strenuous exercise in older adults.

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The Effects of Caffeine Mouth Rinsing on Exercise Performance: A Systematic Review

Alex M. Ehlert, Hannah M. Twiddy, and Patrick B. Wilson

Caffeine ingestion can improve performance across a variety of exercise modalities but can also elicit negative side effects in some individuals. Thus, there is a growing interest in the use of caffeine mouth rinse solutions to improve sport and exercise performance while minimizing caffeine’s potentially adverse effects. Mouth rinse protocols involve swilling a solution within the oral cavity for a short time (e.g., 5–10 s) before expectorating it to avoid systemic absorption. This is believed to improve performance via activation of taste receptors and stimulation of the central nervous system. Although reviews of the literature indicate that carbohydrate mouth rinsing can improve exercise performance in some situations, there has been no attempt to systematically review the available literature on caffeine mouth rinsing and its effects on exercise performance. To fill this gap, a systematic literature search of three databases (PubMed, SPORTDiscus, and Web of Science) was conducted by two independent reviewers. The search resulted in 11 randomized crossover studies that were appraised and reviewed. Three studies found significant positive effects of caffeine mouth rinsing on exercise performance, whereas the remaining eight found no improvements or only suggestive benefits. The mixed results may be due to heterogeneity in the methods across studies, interindividual differences in bitter tasting, and differences in the concentrations of caffeine solutions. Future studies should evaluate how manipulating the concentration of caffeine solutions, habitual caffeine intake, and genetic modifiers of bitter taste influence the efficacy of caffeine mouth rinsing as an ergogenic strategy.

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Sodium Bicarbonate Supplementation Does Not Improve Running Anaerobic Sprint Test Performance in Semiprofessional Adolescent Soccer Players

Rodrigo dos Santos Guimarães, Alcides Correa de Morais Junior, Raquel Machado Schincaglia, Bryan Saunders, Gustavo Duarte Pimentel, and João Felipe Mota

Ergogenic strategies have been studied to alleviate muscle fatigue and improve sports performance. Sodium bicarbonate (NaHCO3) has improved repeated sprint performance in adult team-sports players, but the effect for adolescents is unknown. The aim of the present study was to evaluate the effect of NaHCO3 supplementation on repeated sprint performance in semiprofessional adolescent soccer players. In a double-blind, placebo-controlled, crossover trial, 15 male semiprofessional adolescent soccer players (15 ± 1 years; body fat 10.7 ± 1.3%) ingested NaHCO3 or a placebo (sodium chloride) 90 min before performing the running anaerobic sprint test (RAST). A countermovement jump was performed before and after the RAST, and ratings of perceived exertion, blood parameters (potential hydrogen and bicarbonate concentration), and fatigue index were also evaluated. Supplementation with NaHCO3 promoted alkalosis, as demonstrated by the increase from the baseline to preexercise, compared with the placebo (potential hydrogen: +0.07 ± 0.01 vs. −0.00 ± 0.01, p < .001 and bicarbonate: +3.44 ± 0.38 vs. −1.45 ± 0.31 mmol/L, p < .001); however, this change did not translate into an improvement in RAST total time (32.12 ± 0.30 vs. 33.31 ± 0.41 s, p = .553); fatigue index (5.44 ± 0.64 vs. 6.28 ± 0.64 W/s, p = .263); ratings of perceived exertion (7.60 ± 0.33 vs. 7.80 ± 0.10 units, p = .525); countermovement jump pre-RAST (32.21 ± 3.35 vs. 32.05 ± 3.51 cm, p = .383); or countermovement jump post-RAST (31.70 ± 0.78 vs. 32.74 ± 1.11 cm, p = .696). Acute NaHCO3 supplementation did not reduce muscle fatigue or improve RAST performance in semiprofessional adolescent soccer players. More work assessing supplementation in this age group is required to increase understanding in the area.

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Acute Consumption of Varied Doses of Cocoa Flavanols Does Not Influence Exercise-Induced Muscle Damage

Liam D. Corr, Adam Field, Deborah Pufal, Jenny Killey, Tom Clifford, Liam D. Harper, and Robert J. Naughton

Polyphenol consumption has become a popular method of trying to temper muscle damage. Cocoa flavanols (CF) have attracted attention due to their high polyphenol content and palatability. As such, this study will investigate whether an acute dose of CF can aid recovery following exercise-induced muscle damage. The study was a laboratory-based, randomized, single-blind, nutrient-controlled trial involving 23 participants (13 females and 10 males). Participants were randomized into either control ∼0 mg CF (n = 8, four females); high dose of 830 mg CF (CF830, n = 8, five females); or supra dose of 1,245 mg CF (CF1245, n = 7, four females). The exercise-induced muscle damage protocol consisted of five sets of 10 maximal concentric/eccentric hamstring curls and immediately consumed their assigned drink following completion. To measure muscle recovery, maximal voluntary isometric contraction (MVIC) of the knee flexors at 60° and 30°, a visual analog scale (VAS), and lower-extremity function scale were taken at baseline, immediately, 24-, 48-, and 72-hr postexercise-induced muscle damage. There was a main effect for time for all variables (p < .05). However, no significant differences were observed between groups for all measures (p ≥ .17). At 48 hr, there were large effect sizes between control and CF1245 for MVIC60 (p = .17, d = 0.8); MVIC30 (p = .26, d = 0.8); MVIC30 percentage change (p = .24 d = 0.9); and visual analog scale (p = .25, d = 0.9). As no significant differences were observed following the consumption of CF, there is reason to believe that CF offer no benefit for muscle recovery when ingested acutely.

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Worth the Weight? Post Weigh-In Rapid Weight Gain is Not Related to Winning or Losing in Professional Mixed Martial Arts

Christopher Kirk, Carl Langan-Evans, and James P. Morton

Body mass (BM) manipulation via rapid weight loss (RWL) and rapid weight gain (RWG) is a common practice among mixed martial art (MMA) athletes to ensure qualification for the division in which the athlete wishes to compete. Professional MMA competitors in California are required to weigh in twice: 24 hr prior to competition and immediately prior to the bout after they have typically engaged in RWG. In analyzing data from five MMA events sanctioned by the Californian State Athletic Commission, the authors used Bayesian analyses to compare bout winners (n = 62) and losers (n = 62) in terms of in-competition BM (in kilograms) and the amount of BM regained between the two weigh-ins (in kilograms). These data do not support the hypothesis that differences in in-competition BM (Bayes factor [BF10] = 0.667, d = 0.23) or the amount of BM regained between the two weigh-ins (BF10 = 0.821, d = 0.23) determine winning or losing. In addition, there was no statistical difference between bouts ending via strikes, submission, or decision for either in-competition BM (BF10 = 0.686, ω2 < 0.01) or the amount of BM regained between the two weigh-ins (BF10 = 0.732, ω2 = 0.054). In conclusion, the authors report for the first time that the magnitude of RWG does not predict winning or losing in a professional cohort of MMA athletes. In addition, they also report that MMA athletes typically compete at a BM that is at least 1–2 divisions higher than the division in which they officially weighed-in. These analyses may provide impetus for governing bodies and coaches to enact changes at both professional and amateur levels to reduce negative health consequences associated with extreme RWL and RWG.

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Volume 30 (2020): Issue 4 (Jul 2020)