## 3 Results and Discussion
### Other Substances
#### 3.1.6 Other Variables
Supporters of the swing start (between 60 and 100 rpm) assume that this provides a faster increase in maximum power. On the other hand, standardisation is easier with a stationary start, and it should be possible to improve its reliability. Both [PERSON] et al. [129] and [PERSON] et al. [125] studied the difference between the start launched and the start from a standstill, finding significant differences in PP and the time in which it is reached, in addition to the peak cadence recorded. Despite more time being required to reach the peak with a stationary start, PP was significantly (11%) higher when compared to a moving start;
- The amount of lean body mass is one of the most important performance variables in the test, and when expressed in absolute values, the PP of a WAT is significantly lower in women. In one case studied, the difference between men and women was 51, 17 and 5% when PP was expressed as W, W/kg and W/kg lean body mass, respectively [130]. In contrast to the power expressed as W or W/kg, the difference in PP in terms of lean body mass between genders was not found to be significant, while in another study, absolute PP was 35% higher in men than in women [131]. This difference was only 10% when PP was related to kg lean body mass. Anthropometric variables accounted for less than 50% of the variation in PP in men, while in women, thigh volume represented 66% of the variation in PP [131];
- With regard to the type of cyclo-ergometer used for the test, or rather the type of resistance provided by the cyclo-ergometer used, there may be differences that modify the results obtained, since output power at crank level is greater than the power dissipated at flywheel level due to friction energy losses in the chain and sprockets. This energy loss is considered to be in the order of 5 to 9% [132]. In the case of a Monark ergometer (with which the test was initially designed), losses were around 2 and 4% for 150 and 300 W, respectively [133]. WAT performance was compared between a cycle-ergometer with mechanical resistance and another with a magnetic brake. Fifteen healthy subjects performed a WAT on a mechanical resistance cyclo-ergometer and a magnetic resistance cyclo-ergometer, with no difference being found between the two in terms of PP. In the case of the magnetic cyclo-ergometer, PP was reached later, while MP was lower. The magnetic cyclo-ergometer provides clearly different performance measurements, albeit giving rise to WAT results that may be used to evaluate anaerobic fitness [134]. [PERSON] et al. also concluded that PP, MP, lowest power, fatigue rate, maximum speed as rpm and amount of total energy expenditure demonstrated high reliability in magnetic cyclo-ergometers [135]. Conversely, [PERSON] et al. stated that friction-loadedcyclo-ergometers might underestimate the power generated by the subject because they do not take into account acceleration of the flywheel [136]. This review aims to analyse the variables of the protocol that affect the WAT result. Although much research has been carried out on this test, there is no consensus on the results obtained for many of the variables studied (ACTN3 gene or nitrate supplementation), and other variables have hardly been studied (compression garments or vibration warm-up). On the other hand, it would be interesting to study in depth the relationship between more current variables such as genetics or microbiota and performance in the WAT.