## 1 Introduction  
Today's sporting demands are higher than in the past, while the available time and conditions for training sessions are not always desirable for coaches, always looking for strategies to develop athletes' physical and tactical skills and improve the performance in the competitive moment. The management and monitoring of players' training load is vital to team success, especially in soccer, which is a high-intensity sport of intermittent bouts of activity, implying a substantial demand on the aerobic system [1]. Therefore, aerobic profiles are strongly related to performance-orientated outcomes [2]. Conventional endurance training, such as steady-state or extensive interval training, has traditionally been part of soccer coaches' aerobic training programs as it can enhance endurance capabilities [3]. Furthermore, athlete specific physical fitness, among which agility, speed or strength, have justified specific approaches and detailed analysis in scientific research [4]. Nevertheless, versions of the game may emerge from the interaction of different task manipulations and, if properly designed, new game forms may contribute to a higher and adjusted exertion level of the players [5]. Among these, the development of tactical and technical skills and, possibly, physiological/physical capacities [6], which are relevant since this sport requires an efficient collective organization and, simultaneously, specific development of each player, considering the individual and group framework/perspectives [7]. Small-sided games (SSGs) combine physical, technical, and tactical components, and have been recommended for performance enhancements [8]. Recently, the effects of SSGs were summarized across sixteen studies drawn from multiple sports and population types [5]. The authors concluded that SSGs were more effective for the development of skill and endurance than traditional conditioning or training. Even recreational soccer organized as SSG was recently indicated as an intense activity involving endurance, strength, aerobic, and anaerobic high-intensity interval training (HIIT) elements [9], highlighting the complexity of soccer dynamics expressed in collective and individual actions to be performed by the players [10]. SSGs are currently one of the most common practices used by coaches in their daily work, in order to develop technical and tactical skills, as well as the endurance capacity of their players [11]. The most common analyzed responses are physiological (heart rate, blood lactate), physical (distances, speeds, time), perceptual and technical [12]. Although the most examined variables are the pitch size, player number and the multiple combinations of them [13], other aspects have received attention in research such as inclusion of goalkeepers (GK) [14]. However, the shortage of studies using different intermittent regimens of SSGs and its consequences on training load [15; 16] do not provide coaches with clear guidelines to understand the real impact of different regimens, in terms of the overall stimulus per set and the possible drop in performance throughout the task. With regard to the types of scoring in SSGs, it was previously found that the stop-ball SSG (in a 1 m wide zone behind the end line) induced higher heart rate (HR) values than the small-goal SSG (score in small goals placed at the center of the end line) when using three pitch dimensions (10 \(\times\) 15 m, 15 \(\times\) 20 m, and 20 \(\times\) 25 m) and within three game formats (2 vs. 2; 3 vs. 3 and 4 vs. 4 players) [17; 18]. Although smaller game formats seem to promote a higher exercise intensity and number of decelerations actions in professional soccer players [19], it was reported that both 4 vs. 4 SSGs and 15 sec-15 sec HIIT sessions induced similar physiological responses. However, HIIT produced a mood disturbance, while SSG ensured mood balance [20]. Furthermore, the majority of SSGs studies were conducted with youth or non- professional soccer players.