Exploration of the effect of small sided games on the technical skills, internal and external loads of main and joker players Aliasker Kumak, Ali Kizilet, Tuba Kızılet Bozdoğan Marmara University Institute of Health Sciences, Istanbul Abstract. Introduction: Te aim of the study is to explore the impact of main and joker players on technical skill re- sponses and internal and external load levels in SSGs. Methods: Te participants of the study are 8 elite U17 players who plays in the academy of a professional team training regularly at least fve days a week. Te height of the participants is 178.9 ± 3,2cm, the body mass is 71,6 ± 4,6 kg and body mass index is 20,01 ± 1,03 kg/m’. SSGs have been performed in a 15x25 meters feld, without jokers (3x3), with 1 joker (3x3+1j) and with 2 jokers (3x3+2j). While analyzing data, as a conclusion of test of normality; for the group of 2 Independent Group T-Test or Mann Whitney U test; for the groups of 3 or more ANOVA or Kruskal Wallis H Test have been performed. Te signifcance level has been evaluated as p<0,05. Results: Tere was no statistically sig- nifcant diference among HR, HRmax, HRmax% levels of the players (p>0,05). Signifcant diference was detected in 2 joker games (3x3+2j) in total distance, minute/distance, maximum speed and high intensity running distances of the main players (p<0,05). It is determined that the lactate level and rate of perceived exertion of main players were signifcantly higher compared to joker players (p<0,05). Conclusions: At the end of the study, it was observed that the use of joker players which provides numerical inferiority/superiority in SSGs efects internal and external load responses of both main and joker players while making the games more fastmoving. Key words: soccer, small sided games, game with joker, technical skill, internal and external load. Original article Progress in Nutrition 2021; Vol. 23, N. 2: e2021207 DOI 10.23751/pn.v23i2.11750 © Mattioli 1885 Introduction A soccer match is a competition where 2 oppo- nent teams try to be successful or outclass one another during 90 minutes in a 100x70 feld by exhibiting mul- tiple skills, tactical behaviors, perception and decisions such as sprint, jogging, turns, feint, tackles, shooting, duels, either consecutively or in diferent times (1,2). While elite soccer players cover a distance of approxi- mately 10-12 km. during a competition, the majority of their movements in total distance is aerobic. While high-intensity movements such as sprints, turns, jumps, duels are critical in competitions, high-intensi- ty actions are required to be produced by soccer players via anaerobic metabolism (1, 3, 4). Professional soccer players are known to cover more distance compared to amateur soccer players (3, 5). Soccer-specifc SSGs are often used by coaches as a training method (6, 7, 8), as they refect many skills or activities that the team or players need during a soccer game at the same time (9, 10). Many movement activities such as technical skills, tactical behavior, physiological responses, physi- cal activities that occur during the soccer match are ap- plied practically and very easily by the coaches by add- ing diferent aims, goals or rules in SSGs (11, 12, 13). Compared to the traditional training method (such as revealing the situation in a static environment with a large number of repetitions of the drill), SSGs are per-