## 3 Results and Discussion
### Influential Variables in the Wingate Anaerobic Test
#### 3.1.4 Supplementation
[65] on active subjects who were given 5 g of \(\beta\)-alanine per day (divided into two or three shots per day) for one week found no improvement in power levels obtained in the WAT, although an increase in both maximum and average cadence was recorded. [PERSON] [66] also researched whether applying 3.2 g per day or 6.4 g per day of \(\beta\)-alanine over 4 weeks improved the results of a WAT in 23 untrained adult males and observed no improvement in peak power and fatigue rate. He, therefore, concluded that although many studies reinforce the idea that \(\beta\)-alanine improves anaerobic performance, there are also many variables to be taken into account to substantiate this claim: composition of the subjects' muscle fibres, duration of the test and control of the training carried out by the subjects during the period in which the supplement is taken. Lastly, and in the same vein, [PERSON] et al. [67] explained the of range results obtained following supplementation with \(\beta\)-alanine by the variety of supplementation periods used, the duration of the stimulus to which the subjects are exposed and the subjects' level of training. They concluded that a 30 s stimulus seems too short to be influenced by supplementation of \(\beta\)-alanine. Caffeine  
There are several studies related to the ergogenic effects of caffeine and performance in the WAT. For example, in a study conducted on nine active subjects who were given 6 mg/kg body weight of caffeine, [PERSON], [PERSON] et al. [68] reported an ergolytic effect of caffeine intake compared to placebo on energy production (power generated). In contrast, no significant effect was observed with caffeine intake in 18 active men, who were given 5 mg/kg body weight, in follow-up work by the same authors, [PERSON], [PERSON] et al. [69]. On the other hand, in a study by [PERSON] et al. [70] on nine experienced cyclists, who were given 280 mg or placebo and performed the WAT with 9% of body mass as resistance, they found no significant correlation between caffeine intake and anaerobic performance in such cyclists. Additionally, when [PERSON], [PERSON] et al. [71] provided some 22 male PE students with a drink containing 80 mg of caffeine, 1 g of taurine and 27 g of carbohydrates, while the control group was given a drink with carbohydrates but no taurine or caffeine, improvements were recorded in PP and MP following a WAT with an 8.7% endurance of body weight. Most of the studies that explored this issue have small sample sizes, which, as a result, may have little power to detect any statistical significance (at an a priori alpha level of 0.05), when in fact, there may be a real effect. A way to alleviate these limitations (by increasing statistical power over individual studies) is to perform a meta-analysis, and a 2017 study exists on this topic by [PERSON] et al. [72]. This meta-analysis, on which I base the conclusion of the ergonomic effect of caffeine on performance in the WAT, concluded after reviewing 16 studies that met the characteristics deemed necessary by the author, that there was a significant difference between trials with a placebo and with caffeine in the production of maximum and average power. Similarly, [PERSON] et al. [73] observed an improvement in maximum power in the WAT when providing 22 males with 5 mg/kg, although they did not observe any improvements in MP or PP. It is very important to highlight the idea referred to by [PERSON], [PERSON] et al. [74] in their research. In addition to finding an ergogenic improvement with caffeine (5 mg/kg body mass) in PP obtained in repeated 6 s sprints performed by 14 well-trained men, they concluded that perhaps the reason why many of the previous studies into the ergogenic effects of caffeine on maximum power did not achieve higher power levels might be that they used too small an amount. It may also be, as [PERSON], [PERSON] et al.