Current training methods seek to optimize individuals' physical fitness as much as possible in the shortest possible training time. This is a characteristic of different training methodologies that are applied to improve health and physical performance. These methodologies are being developed and improved in the sports environment, notably High-Intensity Interval Training (HIIT) and Complex Training, among others. The combination of these training methods, applied to the preseason in soccer, must be carefully manipulated in order to obtain the best possible results in a short period of time.