Background Caffeine (CAF) supplementation could have a positive impact on physical performance and sport abilities. Nevertheless, the CAF-induced, dose-dependent influence on discipline-specific performance and combat activity in combat sports have not been sufficiently investigated. The aim of this study was to examine the effect of single ingestion of 3, 6, or 9 mg/kg body weight of CAF and placebo (PLA) on judo-specific performance and sparring combat activities. Methods In a randomised double-blind placebo-controlled cross-over design, acute pre-exercise supplementation with CAF (3, 6, or 9 mg/kg body weight) and placebo PLA in 22 male highly-trained judoists was examined. The study protocol involved five separate testing sessions using the Special Judo Fitness Test (SJFT) with heart rate monitoring, three judo sparring combats and evaluation of the rate of perceived exertion (RPE) using the Borg scale. Results Six and 9 mg/kg CAF improved SJFT performance, while 9 mg/kg increased combat activity. Three mg/kg CAF lacked any apparent positive ergogenic effect. Among athletes, who include CAF-containing products in their habitual diet (consumers), only 9 mg/kg CAF effectively enhanced SJFT performance, while in those who do not consume CAF-containing products at regular basis (non-consumers), the enhancing effect was achieved even at 6 mg/kg. Conclusions Regarding combat sports, higher (6–9 mg/kg) than currently recommended CAF dosages (3–6 mg/kg) are apparently more effective in terms of judo-specific performance. However, the ergogenic CAF effect is not only dose-dependent, but it is also related to customary CAF consumption. Trial registration Clinical Trials Gov, NCT03822663 . Registered 28 January 2019 - Retrospectively registered Electronic supplementary material The online version of this article (10.1186/s12970-019-0305-8) contains supplementary material, which is available to authorized users.

This single-arm interventional study examined the effect of a 4-week ketogenic diet (KD) on aerobic capacity and discipline-specific performance in female (n = 11) and male (n = 11) CrossFit-trained athletes. The participants performed incremental cycling (ICT) and Fight Gone Bad (FGB) tests after consuming a customary diet and a KD. Pre- and post-ICT exercise blood samples were also analysed. Consuming a KD had a slight impact on aerobic capacity and no relevant effect on CrossFit-specific performance. In females, consuming a KD led to an 10.4% decrease in peak oxygen uptake during the ICT (p = 0.027) and resulted in certain alterations in haematological parameters (haemoglobin (HGB), mean corpuscular HGB, and mean corpuscular HGB concentration). Furthermore, in males, alanine aminotransferase activity increased with a simultaneous improvement in the post-ICT blood acid–base balance after consuming a KD. The pre-exercise bilirubin concentration was also elevated in the entire group after consuming a KD. In conclusion, female CrossFit-trained athletes seem to be prone to aerobic performance decrements and increased risk of developing haematological disturbances when consuming a KD. In males who consumed a KD, there was an undesirable alanine aminotransferase elevation and a small tendency towards improved acid–base status. Moreover, consuming a KD had no effect on discipline-specific performance in CrossFit-trained athletes.

Bovine colostrum (BC) is a promising natural product applied to improve immunological functions. However, there is very little evidence on the true benefits of BC treatment on the immune function of trained and physically active people; moreover, there is no consensus on the supplementation strategy. For this reason, the aim of this meta-analysis was to quantify the effects of BC supplementation on immunological outcomes in physically active people. Data from 10 randomised controlled trials (RCTs) investigating the effect of BC supplementation in athletes and physically active adults were analysed, involving 239 participants. The results show that BC supplementation has no or a fairly low impact on improving the concentration of serum immunoglobulins (IgA, IgG), lymphocytes and neutrophils, and saliva immunoglobulin (IgA) in athletes and physically active participants. Previous research has shown BC to reduce upper respiratory tract infections; nevertheless, there is a gap of scientific knowledge on the mechanisms underlying these effects. Future RCTs are needed to focus on finding these mechanisms, as well as on preparing a clear consensus on a BC supplementation strategy in trained athletes and the physically active population.

Colostrum Bovinum is the first milk secreted from the mammary glands of mammals after parturition. In calves, it is the only way to provide immunoglobulins, which are responsible for the proper maturation of the immune system. The benefits of calf colostrum have contributed to the investigation of the effects of colostrum in humans. Although the health properties of colostrum are not fully understood, its supplementation in athletes has been particularly interesting for over 20 years. The presence of growth factors, immunoglobulins, cytokines, lactoferrin and hormones suggests that colostrum may improve the functioning of the digestive, immune and neuroendocrine systems, and exercise performance. The administering of colostrum seems to be most effective during periods of high intensity training, probably due to its high concentration of IGF-I, the ability to increase muscle buffering capacity or its high SIgA concentration. Due to the lack of adjustment of specific doses and the period of colostrum supplementation, it is necessary to conduct further studies on the impact of colostrum supply on exercise performance. The aim of this review article is to analyze the available experimental studies and reviews on the use of colostrum in sport and to draw attention to the possibility of using colostrum to improve the health of athletes and the results they can achieve in their chosen sports.

This interventional study examined the effect of a four-week vegan diet (VegD) during a four-week high-intensity functional training (HIFT) on performance, training results and blood biochemical indices in female (n = 12) and male (n = 8) moderate-trained CrossFit participants. The whole study group performed the maximum number of repetitions with a load of 70% one repetition-maximum (1RM) and a modified Fight Gone Bad (FGBMod) test before and after a dietary intervention (the group was divided to follow a VegD or a traditional mixed diet (MixD)) in a randomised and parallel design. Pre-exercise resting blood samples were also analysed. There was a significant improvement in the number of repetitions performed at a load corresponding to 70% of 1RM in the classic squat in the MixD group (p < 0.001), and in the classic deadlift in the VegD group (p = 0.014). Furthermore, there was a significant improvement in the results of the FGBMod performance test after a MixD. Moreover, an improvement in some exercises in the modified FGBMod test (Wall Ball after the VegD and the MixD, and rowing after the MixD) was also observed. However, differences between the MixD and the VegD groups were not clinically relevant. In conclusion, the short-term study conducted here indicated that a VegD in HIFT training positively affects strength endurance in the classic deadlift but is unlikely to be more beneficial in improving performance than a MixD.