The aim of this study was to determine the prevalence of SS use in elite fencers with respect to sex and competitive level (national vs international). Although there are few studies in different contexts (i.e., training and sports nutrition fields) in elite fencers [3,4,5, 7], this is the first study that specifically analyzes the consumption of SS in fencing.
The proportion of SS consumption differs greatly depending on a multitude of variables, such as the sports modality that has the greatest difference between them (30–95%) [14, 18]. Although our study’s results place SS consumption within this range (46.9%), this was lower than similar populations from other sports modalities that reported consumption between 64 and 81.7% [16, 19, 27, 28]. This places SS consumption within our sample of elite fencers below the findings of recent studies that have evaluated the consumption of SS in elite athletes.
In addition to the sport modality, two variables that most influence the consumption of SS are the level of competition and sex . The current hypothesis is that fencers at a higher level of competition  who are male  consume more SS. However, the results obtained in our study do not show a significant difference between national and international fencers, which contrasts with studies in which there are significant differences international-level athletes [9, 16, 18, 21, 27]. Similarly, no differences were observed in the prevalence of SS use among athletes according to sex, which is in line with the findings of the meta-analysis by Knapik et al. (2016) . These data contrast with those currently found in elite Spanish athletes in which a higher consumption was observed in men vs women, 67% vs 58% (27) and 54.8% vs 45.5% .
As previously stated, our data agrees with the principal reason for SS consumption in competitive fencers: performance improvement; however, the proportion of fencers who report this motivation (34.2%) is lower than that reported in athletes of other sports modalities (45–77.8%) [9, 16, 21, 28].
The most frequent places of SS purchase were supermarkets (38.9%) and pharmacies (25%). It should be added that the data contrast with those obtained in a similar population that primarily attended specialty stores (45%) or sought sponsorships and the internet (25%) . Although there is similarity in terms of the data obtained from purchasing in pharmacies in dinghy sailors , supermarkets are not the usual place of SS purchase in currently published studies [9, 14, 16, 22].
Bearing in mind that the possible effects of poor SS selection can lead to unintentional doping and/or health risks, the sources of information in which athletes rely on for SS consumption are important . Although dietitian-nutritionists or sports doctors are the most ideal expert sources of SS consumption , the most frequent advisors of SS consumption were friends (26.7%), doctors (23.3%), and coaches (20.0%). These data are similar to those reported in studies carried out in young athletes of different sports modalities [9, 32] or in amateur adult athletes [19, 23]. Our study demonstrates the need to influence the correct choice of sources of advice on SS, although in this case, the sample presents a low consumption of SS from group C according to the AIS . Male fencers were more likely to seek advice from doctors (p = 0.016)—a question that may be related to their greater intake of iron medical supplements (p = 0.039).
The moment of SS ingestion plays an important role in optimizing performance and recovery . No differences were observed between levels of competition; however, significant differences were observed based on sex (p = 0.002), establishing that men preferred intake SS during sports activity while women throughout the whole day.
Although the data obtained in relation to the SS ingestion moment were in general and not in a specific way for each of the SS, the fact that only 14.3% of the athletes in the sample consumed SS prior to the effort has a practical implication, since, the consumption of an SS consumed by 28.6% of the sample, such as caffeine, should be ingested 45–60 min before the effort [10, 34].
The mean number of SS consumed by the sample is lower than that reported in a recent study of sailors (3.9 SS) , squash players (8.4 SS) , and other modalities such as bodybuilding in which they reported mean intakes of 20 SS daily . The total intake of SS did not differ according to sex or level of competition, which run contrary to the hypothesis that sex and level of competition influence SS consumption [10, 18]. Similarly, statistically significant differences of total SS consumed were not observed by sex or level of competition in Groups A, B, and C . These results are similar to those obtained from squash players where no significant differences were observed between the consumption of supplements in groups A, B and C when comparing athletes of international vs national level . These results, however, run contrary to that of elite sailors where there was a higher consumption of Groups A/B SS in international-level sailors and Group C SS in national-level sailors . According to the results obtained in our study, there were only differences in the group of medical supplements (under group A) when comparing athletes by sex: men reported higher SS consumption. This is similar to results found in another study where there were only differences in sport foods by competitive level .
When comparing the SS most consumed by the sample according to sex, a higher consumption of whey proteins was observed in women when compared to men that reported no consumption (25.8% vs 0%; p = 0.020). This contrasts with a study carried out in 504 Spanish elite athletes of different modalities in which men had higher protein supplementation (50.9% vs 29%; p < 0.01) . Among other reasons, this can be explained by a greater need and / or concern to improve strength and muscle mass through the use of supplements in male athletes [14, 36,37,38]. In addition to protein supplementation, a significant difference was observed in terms of iron consumption: women reported lower consumption (6.5% vs 33.3%; p = 0.039; OR = 0.39 [0.21–0.73]), contrary to those reported in the aforementioned study by Aguilar-Navarro et al. (2020) (22% vs 11%; p = 0.01) . A possible explanation for lower iron consumption amongst our study’s participants is that unlike male fencers, female fencers are less frequently recommended iron supplementation by doctors who might recommend it for prophylactic purposes in men. This could lead to health and performance problems for women since the prevalence of iron deficiency is higher in female athletes , because of higher iron demands from menstruation . Furthermore, both findings are contrary to what was reported in a meta-analysis carried out by Knapik et al. (2016) in which iron supplementation was higher in women and protein supplementation (including creatine) was higher in men .
When comparing the SS most consumed by the sample according to competitive level (international vs national), the only differences were observed in iron consumption, which was greater in international-level athletes (24.2% vs 0%; p = 0.04). These results differ from those reported in elite Spanish sailors that had no differences in SS use . However, our results are similar to those found in Spanish squash players that had higher SS consumption at the international level without statistical significance (35.7% vs 14.3%; p = 0.11). The higher consumption in international-level athletes could be explained by iron being an essential component of myoglobin and hemoglobin, which ensure adequate oxygen supply to skeletal muscles . A nutritional deficiency may compromise energy metabolism, thereby increasing glycolysis while reducing energy efficiency, performance, and training adaptations .
An important finding of the present study is that the 3 most consumed SS by the entire sample were sports drinks, sports bars and caffeine. According to sex, sport drinks, sports bars and iron were the most consumed by men while sports drinks, sports bars and caffeine by women respectively. In addition, according to competition level at international level consumed sports drinks, sports bars and caffeine, while at national level reported sports drinks, sports bars and caffeine/vitamin C (same consumption level in this category). These findings are in line with the data reported in other studies in which SS are some of the most consumed substances by elite athletes of various sports modalities [9, 16, 28].
In fencing, fencers are equipped with protective clothing that increase body temperature, the sweating rate, and thus, fluid and electrolyte losses . The high consumption of sport drinks (44.9%) in our sample may be due to these characteristics. Thus, an inadequate fluid-balance during training or competitions could provoked a loss of performance (i.e., endurance, muscle power, attention, or speed in decision making actions) [6, 7]. Sports drinks may not only help to maintain fluid balances, but also retain carbohydrates that maintain carbohydrate oxidation and blood glucose levels while reducing the use of muscle and liver glycogen stores. Added together, sport drinks can contribute to improvements in performance. Although it is to be noted that this may depend on environmental conditions, training intensity, and competition duration . In addition, it should be underscored that the consumption of sport drinks was higher in men than in women (61.1% vs 35.5%). Thus, this could be due to a higher rate of sweating in [6, 41]. which would be aggravated by the characteristics previously mentioned in this sport modality .
Sport bars were the second most consumed SS by the sample (38.8%) with no differences in performance level or sex. These results are similar to those observed in other types of sports [9, 16]. This may be due to the usefulness of this supplement in international trips and competitions since they are an easily accessible resource for consumption and nutrient delivery [10, 11] on the one hand, and can serve in this type of athletes before, during and then in more demanding training and competitions compared to nationals .
Caffeine was the most used SS within the AIS Group A ergogenic aid subgroup (28.6%). Although there were no significant differences by competitive level and sex, its consumption was somewhat higher in national-level (31.3% vs. 27.3%) and women (32.3% vs 22.2%) fencers. These data are similar to those found in certain studies [16, 18], but contrary to others [9, 21]. Caffeine is one of the few SS studied in fencing [43, 44]. In a study by Bottoms et al. (2013)  conducted in professional fencers of both sexes, it was found that supplementation with 3 mg/kg of caffeine had no effect on the information processing speed measured by a Stroop test the ability on a lungest test or hit a target, although the ratings of perceived exertion (RPE) decreased. Doyle et al. (2016)  analyzed the effect of different doses of caffeine (from 1.5 to 7.5 mg/kg) on arousal, response time, and accuracy during a simulated fencing practice in competitive-level fencers. Caffeine supplementation increased arousal in a dose-dependent relationship, although an ergogenic effect was only observed from supplementation with doses of 4.5–6 mg / kg. Thus, it was found that the increase in psychological tension levels within an optimal range is related to improved performance . Given that caffeine has a chemical form similar to adenosine by blocking adenosine receptors, this supplementation affects neuromuscular performance, mood, and subjective perception of effort [46, 47], allowing for a fencer to achieve an optimal state of mood and reduce RPE [43, 44].
In addition to the previous SS, fencers can improve their sports performance with other ergogenic aids from Evidence Group A (AIS 2019) that had 0% prevalence of consumption in the present sample, such as B-alanine (due to its ability to regulate pH at the intracellular level) [48,49,50,51], sodium bicarbonate (due to improvement in extracellular pH regulation) [52, 53], and / or beetroot juice (capable of improving contractility and muscle power) [53, 54].
Regarding the SS of group B (AIS, 2019) , the consumption of vitamin C (20.4%) stood out in men (27.8% vs 16.1%) and national fencers (31.3% vs 15.2%). These data are below comparing meta-analysis by Knapik et al. (2016)  that placed their consumption at around 32%, but similar to those reported in Dutch athletes of different disciplines, which placed it at around 23% . However it is worth to mentioned that vitamin C consumption was higher in international squash players (35.7% vs 25%) although it was not significant . Regarding the SS of group C (AIS, 2019) , it is worth highlighting the consumption of green tea for the total sample (18.4%), regardless of sex and level of competition (16.7–19.4%). Green tea use is typically more common in recreational athletes who usually use it for aesthetic purposes (i.e., fat loss) despite no evidence for its use existing [17, 22], especially within elite athletes [9, 16, 21, 28]. This may be due to the fact that the most frequent advisor in the present sample were friends, which could lead to the consumption of a supplement without any level of evidence.
Although the use of supplements is widespread among athletes, it is important that athletes and nutrition specialists who care for them perform a cost-benefit analysis on their appropriate and responsible use [11, 55]. This analysis must be developed based on the prevalence of SS use in fencers, which is within the values previously reported in athletes of the same competitive level. There were no significant differences by neither sex nor level of competition in the purpose of consumption and the place of SS purchase. Likewise, there were no differences by sex and competitive level in the total consumption of SS, nor in each of the groups of level of evidence. The SS most consumed were sport drinks, bars, and caffeine, presenting differences in the consumption of whey protein by sex and in iron by interaction (sex and level) of competition. These findings highlight the importance of a complete nutritional assessment, as well as the individual context and needs of the athlete at that time . Importantly, the use of SS should not compensate poor food choices and an inadequate diet with the exception of being a short-term supplement when dietary changes are not possible . Also, a well-chosen diet supports the benefits of using evidence-based supplements, whether taken to maximize performance, delay fatigue, alter body composition, or improve health , and that any recommendation for athletes should be based on current scientific data and individual needs.