Effects of Acute Yohimbine Hydrochloride Supplementation on Repeated Supramaximal Sprint Performance

Effects of dietary supplements on athletic performance in elite soccer players: a systematic review

Dietary supplements are widely used among athletes, and soccer players are no exception. Nevertheless, evidence supporting the use of dietary supplements aiming to enhance performance in soccer is somewhat contradictory, scarce, or even nonexistent. Thus, the present study aimed to systematically review and synthesize the effects of dietary supplements on athletic performance (e.g. distance covered, sprinting, jump performance) in elite soccer players. Studies enrolling highly trained, elite, and world-class soccer players using dietary supplements were searched in MEDLINE/PubMed, Web of Science, Scopus, and EBSCO databases in June 2022. In total, 1043 studies were identified, and 18 met the eligibility criteria. The studies evaluated the impacts on athletic performance of several dietary supplements, including caffeine, creatine, protein, beverages with carbohydrates and electrolytes, tart cherry juice, nitrate-rich beetroot juice, sodium bicarbonate with minerals, yohimbine, and a proprietary nutraceutical blend. Caffeine supplementation in doses between 3 and 6 mg/kg of body mass may improve jump height and sprint ability, particularly in female players, but individual response to caffeine must be considered. Creatine may improve sprint, agility, and in female players, jump performance. Protein supplementation can improve sprint and jump performance between matches, especially if protein ingested from food is not up to recommendations. Beverages containing carbohydrates and electrolytes can be used as part of the strategies to achieve carbohydrate intake during training and match-days but used alone do not benefit athletic performance. Tart cherry juice might be useful for maintaining athletic performance after matches that produce higher force loss and exercise-induced muscle damage, although polyphenols from the diet might attenuate the effects of tart cherry supplementation. Nitrate-rich beetroot concentrate can attenuate performance decrease in the days following matches. Further investigation with sodium bicarbonate alone is necessary, as supplementation protocols with elite players included other substances. Finally, the available data does not support yohimbine supplementation or the use of Resurgex Plus® to improve athletic performance in elite soccer players. Still, more well-designed research with elite soccer players is needed to improve support and advice regarding the use of dietary supplements for athletic performance enhancement.

Ammonia Inhalants Enhance Psychophysiological Responses and Performance During Repeated High Intensity Exercise

Purpose: Ammonia inhalants (NH3) are anecdotally used in competition by athletes for their purported stimulant effects. However, evidence on the efficacy of NH3 is conflicting, and little to no studies to date have investigated its effect on repeated exercise. The purpose of this study was to examine the effects of NH3 on psychophysiological responses and performance during repeated high-intensity exercise. Methods: In a counterbalanced crossover design, physically active females completed two repeated high-intensity sprint trials with a different treatment: Control (CON; water) or Ammonia Inhalants (NH3; 0.33 cc). For each trial, participants completed 3 × 15s Wingate anaerobic tests (WAnT) separated by 2 min of active recovery. Prior to each WAnT, participants took a single 3-s inhale of the corresponding treatment. After the succession of each WAnT, heart rate (HR) and rate of perceived exertion (RPE) were documented. Subjective feelings of alertness and "psyched up" energy were measured using a visual analog scale. Trials were separated by at least 48 hr. Results: The results indicate that over the WAnTs, mean power (p = .017) and peak power (p = .006) were significantly higher with NH3 compared to CON despite a lack of changes in fatigue index (p = .928). HR (p = .101) and RPE (p = .897) were not different with varying treatments. Perceived alertness (p = .010) and psyched-up energy (p = .002) were significantly higher with NH3 versus CON. Conclusion: These findings provide empirical support for the use of NH3 to improve repeated high-intensity exercise performance in females that may be underpinned by alterations in subjective alertness and energy.

Unauthorized ingredients in "nootropic" dietary supplements: A review of the history, pharmacology, prevalence, international regulations, and potential as doping agents

The first nootropic prohibited in sport was fonturacetam (4-phenylpiracetam, carphedon) in 1998. Presented here 25 years later is a broad-scale consideration of the history, pharmacology, prevalence, regulations, and doping potential of nootropics viewed through a lens of 50 selected dietary supplements (DS) marketed as "cognitive enhancement," "brain health," "brain boosters," or "nootropics," with a focus on unauthorized ingredients. Nootropic DS have risen to prominence over the last decade often as multicomponent formulations of bioactive ingredients presenting compelling pharmacological questions and potential public health concerns. Many popular nootropics are unauthorized food or DS ingredients according to the European Commission including huperzine A, yohimbine, and dimethylaminoethanol; unapproved pharmaceuticals like phenibut or emoxypine (mexidol); previously registered drugs like meclofenoxate or reserpine; EU authorized pharmaceuticals like piracetam or vinpocetine; infamous doping agents like methylhexaneamine or dimethylbutylamine; and other investigational substances and peptides. Several are authorized DS ingredients in the United States resulting in significant global variability as to what qualifies as a legal nootropic. Prohibited stimulants or ß2-agonists commonly used in "pre-workout," "weight loss," or "thermogenic" DS such as octodrine, hordenine, or higenamine are often stacked with nootropic substances. While stimulants and ß2-agonists are defined as doping agents by the World Anti-Doping Agency (WADA), many nootropics are not, although some may qualify as non-approved substances or related substances under catch-all language in the WADA Prohibited List. Synergistic combinations, excessive dosing, or recently researched pharmacology may justify listing certain nootropics as doping agents or warrant additional attention in future regulations.

Effects of Nutrition Interventions on Athletic Performance in Soccer Players: A Systematic Review

BACKGROUND

More than 270 million participants and 128,893 professional players play soccer. Although UEFA recommendations for nutrition in elite football exist, implementing these guidelines among professional and semiprofessional soccer players remains suboptimal, emphasizing the need for targeted and individualized nutritional strategies to improve adherence to established recommendations.

METHODS

We conducted a comprehensive search in PubMed, Scopus, Web of Science, and clinical trial registers. Inclusion criteria focused on professional or semiprofessional soccer players, nutrition or diet interventions, performance improvement outcomes, and randomized clinical trial study types. We assessed quality using the Risk of Bias 2 (RoB 2) tool. We identified 16 eligible articles involving 310 participants. No nutritional interventions during the recovery period effectively improved recovery. However, several performance-based interventions showed positive effects, such as tart cherry supplementation, raw pistachio nut kernels, bicarbonate and mineral ingestion, creatine supplementation, betaine consumption, symbiotic supplements, and a high-carbohydrate diet. These interventions influenced various aspects of soccer performance, including endurance, speed, agility, strength, power, explosiveness, and anaerobic capacity.

CONCLUSIONS

Specific strategies, such as solutions with bicarbonate and minerals, high carbohydrate diets, and supplements like creatine, betaine, and tart cherry, can enhance the performance of professional soccer players. These targeted nutritional interventions may help optimize performance and provide the competitive edge required in professional soccer. We did not find any dietary interventions that could enhance recovery.

A Matter of Taste: Roles of Taste Preference on Performance and Psychological Responses during Anaerobic Exercise

Various tastes including sweet, bitter, and sour have been shown to differentially influence physiological and psychological processes. Furthermore, ingestion of bitter and sweet solutions has been shown to acutely enhance exercise performance. However, the taste is highly individualized, and it is unclear if preference influences the ergogenic potential of taste. The purpose of this study was to investigate the effects of preferred and non-preferred drink tastes on anaerobic performance and psychological responses thereof. Physically active females participated in two counterbalanced sprint trials each with a different condition: (1) non-preferred taste (NPT), (2) Preferred taste (PT). Participants self-reported taste preferences (sweet, sour, bitter) with the highest-ranked taste being used for the PT condition and the lowest-ranked for NPT. For each visit, participants completed a 15 s Wingate Anaerobic Test (WAnT) prior to (PRE) ingestion of ~20 mL of their NP or PREF taste. Following ingestion, participants completed 2 min of active recovery, rated their taste preference of the solution, and completed another 15 s WAnT. The rate of perceived exertion (RPE), motivation, and enjoyment were measured through a visual analog scale following each WAnT. Anaerobic performance measures and heart rate (HR) were also obtained at the succession of each WAnT. Findings revealed no differences between taste conditions for mean power (p = 0.455), peak power (p = 0.824), or HR (p = 0.847). RPE was significantly lower with PT versus NPT (p = 0.006). Exercise enjoyment (p = 0.022) was higher with PT compared to NPT. NPT resulted in worse motivation compared to PRE (p = 0.001) while no changes were observed between PT and PRE (p = 0.197). These findings suggest that preferred drink taste may not enhance acute performance but improves psychological responses to maximal anaerobic exercise which may have implications for improving exercise training and adherence.

A literature perspective on the pharmacological applications of yohimbine

Introduction: Phytochemicals have garnered much attention because they are useful in managing several human diseases. Yohimbine is one such phytochemical with significant pharmacological potential and could be exploited for research by medicinal chemists. It is an indole alkaloid obtained from various natural/synthetic sources.Aims and Results: The research on yohimbine started early, and its use as a stimulant and aphrodisiac by humans has been reported for a long time. The pharmacological activity of yohimbine is mediated by the combined action of the central and peripheral nervous systems. It selectively blocks the pre and postsynaptic α₂-adrenergic receptors and has a moderate affinity for α1 and α2 subtypes. Yohimbine also binds to other behaviourally relevant monoaminergic receptors in the following order: α-2 NE > 5HT-1A>, 5HT-1B > 1-D > D3 > D2 receptors.Conclusion: The current review highlights some significant findings that contribute to developing yohimbine-based drugs. It also highlights the therapeutic potential of yohimbine against selected human diseases. However, further research is recommended on the pharmacokinetics, molecular mechanisms, and drug safety requirements using well-designed randomized clinical trials to produce yohimbine as a pharmaceutical agent for human use.Key MessagesYohimbine is a natural indole alkaloid with significant pharmacological potential.Humans have used it as a stimulant and aphrodisiac from a relatively early time.It blocks the pre- and postsynaptic α2-adrenergic receptors that could be exploited for managing erectile dysfunction, myocardial dysfunction, inflammatory disorders, and cancer.

PROTEIN BINDING CHARACTERISTICS OF YOHIMBINE, A NATURAL INDOLE ALKALOID BASED DRUG FOR ERECTILE DYSFUNCTION

Even to this day, talking about sexual-dysfunctions largely remains a taboo. Hence less studies were recorded and fewer remedies given. Erectile dysfunction (ED) is one of the most commonly treated psychological disorders which leads to major distress, interpersonal limitation and reduces the quality of life & marriage. This study aimed to assess a plant-derived molecule, Yohimbine (Yoh, a β-carboline indole-alkaloid; often used for ED treatment) and its potential binding phenomenon with hemoglobin (Hb). Successful binding of the Yoh with Hb is evident from spectroscopic and molecular-docking results. Yoh quenched the fluorescence of Hb efficiently through static mode. The binding affinity was in the order of 10⁵ M^-1 with 1:1 stoichiometry. Thermodynamic analyses concluded that the protein-ligand association to be spontaneous and attributed by entropy-driven exothermic-binding. Non-polyelectrolytic factor was the core, dominating factor. The structural aspects have been deciphered through infra-red spectroscopy and computational-methods. The giant 3D-protein moiety was significantly perturbed through drug-binding. Hydrophobic forces and hydrogen bonding participation were stipulated by molecular modeling data. This study reveals the detailed interaction pattern and molecular mechanism of Hb-Yoh binding; correlating the structure-function relationship for the first time; therefore, holds enormous importance from the standpoint of rational and efficient drug-designing & development.