Dietary supplementation is a common strategy to achieve a specific health status or performance benefit. Several investigations have focused on the prevalence of dietary supplement use by athletes. However, information on how athletes manage the use and purchase of dietary supplements is scarce. Five hundred and twenty-seven high-performance athletes (346 males and 181 females), participating in individual and team sports, completed a validated questionnaire about use and purchase patterns of dietary supplements. The dietary supplements were categorized according to the International Olympic Committee (IOC) consensus. Sixty four percent of the athletes (n = 337) used dietary supplements (median = 3; range 1 to 12). Age, sex, type of sport, level of competition, and professionalism influenced the prevalence of dietary supplement use (all p < 0.05). The most prevalent dietary supplement consumed was proteins (41%; n = 137), followed by amino acids/BCAA-based supplements (37%; n = 124). Additionally, as per group of supplements according to IOC consensus, 18% of the supplements were rated as having a low level of scientific evidence (e.g., glutamine, HMB, L-carnitine, etc). Most athletes (45%, n = 152) purchased dietary supplements in a store and 24% (n = 81) obtained them from a sponsor. Most athletes also (42%, n = 141) reported a self-organization of supplementation and did not consult with any professional. Last, 81% (n = 273) of athletes consuming supplements did not know any platform to check supplement safety/quality. For those who do not use dietary supplements (36% of the total sample, n = 190), most reported that they do not consider supplements necessary (72%, n = 137). Dietary supplementation appears to be widely used in sport with a considerable proportion of athletes consuming supplements with low level of scientific evidence. Additionally, athletes seem to rely on inadequate sources of information and may be largely unaware of sources to detect supplement contamination.

The ergogenic effect of caffeine is well-established, but the extent of its consumption in sport is unknown at the present. The use of caffeine was considered “prohibited” until 2004, but this stimulant was moved from the List of Prohibited Substances to the Monitoring Program of the World Anti-Doping Agency to control its use by monitoring urinary caffeine concentration after competition. However, there is no updated information about the change in the use of caffeine as the result of its inclusion in the Monitoring Program. The aim of this study was to describe the changes in urine caffeine concentration from 2004 to 2015. A total of 7488 urine samples obtained in official competitions held in Spain and corresponding to athletes competing in Olympic sports (2788 in 2004, 2543 in 2008, and 2157 in 2015) were analyzed for urine caffeine concentration. The percentage of samples with detectable caffeine (i.e., >0.1 μg/mL) increased from ~70.1%, in 2004–2008 to 75.7% in 2015. The median urine caffeine concentration in 2015 (0.85 μg/mL) was higher when compared to the median value obtained in 2004 (0.70 μg/mL; p < 0.05) and in 2008 (0.70 μg/mL; p < 0.05). The urine caffeine concentration significantly increased from 2004 to 2015 in aquatics, athletics, boxing, judo, football, weightlifting, and rowing (p < 0.05). However, the sports with the highest urine caffeine concentration in 2015 were cycling, athletics, and rowing. In summary, the concentration of caffeine in the urine samples obtained after competition in Olympic sports in Spain increased from 2004 to 2015, particularly in some disciplines. These data indicate that the use of caffeine has slightly increased since its removal from the list of banned substances, but urine caffeine concentrations suggest that the use of caffeine is moderate in most sport specialties. Athletes of individual sports or athletes of sports with an aerobic-like nature are more prone to using caffeine in competition.

Purpose: Dietary supplement use by athletes has been the topic of previous research; however, the lack of homogeneity among published studies makes it difficult to analyze the differences, if any, in the patterns of use between male and female athletes. The aim of this study was to determine gender differences in the patterns of dietary supplement use by elite athletes. Methods: A total of 504 elite athletes (329 males and 175 females) participating in individual and team sports completed a validated questionnaire on dietary supplement use during the preceding season. The dietary supplements were categorized according to the latest IOC consensus statement. Results: A higher proportion of male versus female athletes (65.3 versus 56.5%, p < .05) consumed dietary supplements. Both male and female athletes reported a similar mean consumption of dietary supplements (3.2 ± 2.1 versus 3.4 ± 2.3 supplements/season, respectively; p = .45). Protein supplements were the most commonly consumed supplements in male athletes (49.8%) and their prevalence was higher than in female athletes (29.3%, p < .01). In females, multivitamins (39.4%) and branched-chain amino acids (39.4%) were the most commonly consumed supplements and iron supplementation was more prevalent than in males (22.2% versus 10.2%, p = .01). A higher proportion of male athletes relied on themselves to plan dietary supplements use (48.0%), while female appeared to rely more on doctors (34.0%, p < .01). Conclusion: In summary, male athletes had a slightly higher prevalence in the use of supplements than their female counterparts, specifically regarding protein supplements, and were more involved in the self-prescription of supplements.

Previous investigations have found that several genes may be associated with the interindividual variability to the ergogenic response to caffeine. The aim of this study is to analyze the influence of the genetic variations in CYP1A2 (−163C > A, rs762551; characterized such as “fast” (AA genotype) and “slow” caffeine metabolizers (C-carriers)) and ADORA2A (1976T > C; rs5751876; characterized by “high” (TT genotype) or “low” sensitivity to caffeine (C-carriers)) on the ergogenic response to acute caffeine intake in professional handball players. Thirty-one professional handball players (sixteen men and fifteen women; daily caffeine intake = 60 ± 25 mg·d⁻¹) ingested 3 mg·kg⁻¹·body mass (bm) of caffeine or placebo 60 min before undergoing a battery of performance tests consisting of a countermovement jump (CMJ), a sprint test, an agility test, an isometric handgrip test, and several ball throws. Afterwards, the handball players performed a simulated handball match (2 × 20 min) while movements were recorded using inertial units. Saliva samples were analyzed to determine the genotype of each player for the −163C > A polymorphism in the CYP1A2 gene (rs762551) and for the 1976T > C polymorphism in the ADORA2A gene (rs5751876). In the CYP1A2, C-allele carriers (54.8%) were compared to AA homozygotes (45.2%). In the ADORA2A, C-allele carriers (80.6%) were compared to TT homozygotes (19.4%). There was only a genotype x treatment interaction for the ball throwing from 7 m (p = 0.037) indicating that the ergogenic effect of caffeine on this test was higher in CYP1A2 AA homozygotes than in C-allele carriers. In the remaining variables, there were no genotype x treatment interactions for CYP1A2 or for ADORA2A. As a whole group, caffeine increased CMJ height, performance in the sprint velocity test, and ball throwing velocity from 9 m (2.8–4.3%, p = 0.001–0.022, effect size = 0.17–0.31). Thus, pre-exercise caffeine supplementation at a dose of 3 mg·kg⁻¹·bm can be considered as an ergogenic strategy to enhance some neuromuscular aspects of handball performance in professional handball players with low daily caffeine consumption. However, the ergogenic response to acute caffeine intake was not modulated by CYP1A2 or ADORA2A genotypes.

Purpose: To investigate the effects of acute caffeine (CAFF) intake on physical performance in elite women handball players. Methods: A total of 15 elite women handball players participated in a randomized, double-blind study. In 2 different trials, participants ingested either a placebo (cellulose) or 3 mg of CAFF per kilogram of body mass (mg/kg bm) before undergoing a battery of neuromuscular tests consisting of handball throws, an isometric handgrip strength test, a countermovement jump, a 30-m sprint test (SV) and a modified version of the agility T test. Then, participants performed a simulated handball game (2 × 20 min), and movement patterns were recorded with a local positioning system. Results: Compared with the placebo, CAFF increased ball velocity in all ball throws (P = .021–.044; effect size [ES] = 0.39–0.49), strength in isometric handgrip strength test (350.8 [41.2] vs 361.6 [46.1] N, P = .034; ES = 0.35), and countermovement-jump height (28.5 [5.5] vs 29.8 [5.5] cm; P = .006; ES = 0.22). In addition, CAFF decreased running time in the SV (4.9 [0.2] vs 4.8 [0.3] s; P = .042; ES = −0.34). In the simulated game, CAFF increased the frequency of accelerations (18.1 [1.2] vs 18.8 [1.0] number/min; P = .044; ES = 0.54), decelerations (18.0 [1.2] vs 18.7 [1.0] number/min; P = .032; ES = 0.56), and body impacts (20 [8] vs 22 [10] impacts/min; P = .032; ES = 0.30). However, postexercise surveys about self-reported feelings of performance indicate that players did not feel increased performance with CAFF. Conclusion: Preexercise ingestion of 3 mg/kg bm of CAFF improved ball-throwing velocity, jump, and sprint performance and the frequency of in-game accelerations and decelerations in elite women handball players.

Genetic factors play a significant role in athletic performance and its related phenotypes such as power, strength and aerobic capacity. In this regard, the lack of a muscle protein due to a genetic polymorphism has been found to affect sport performance in a wide variety of ways. α-actinin-3 is a protein located within the skeletal muscle with a key role in the production of sarcomeric force. A common stop-codon polymorphism (rs1815739; R577X) in the gene that codes for α-actinin-3 (ACTN3) produces individuals with the XX genotype that lack expression of a functional α-actinin-3. In contrast, individuals with the R-allele (i.e., RX vs. RR genotypes) in this polymorphism can express α-actinin-3. Interestingly, around ~18% of the world population have the XX genotype and much has been debated about why a polymorphism that produces a lack of a muscle protein has endured natural selection. Several investigations have found that α-actinin-3 deficiency due to XX homozygosity in the ACTN3 R577X polymorphism can negatively affect sports performance through several structural, metabolic, or signaling changes. In addition, new evidence suggests that α-actinin-3 deficiency may also impact sports performance through indirect factors such a higher risk for injury or lower resistance to muscle-damaging exercise. The purpose of this discussion is to provide a clear explanation of the effect of α-actinin-3 deficiency due to the ACTN3 XX genotype on sport. Key focus has been provided about the effect of α-actinin-3 deficiency on morphologic changes in skeletal muscle, on the low frequency of XX athletes in some athletic disciplines, and on injury epidemiology.