Activity breaks cause decrease of the level of physical condition, and therefore disturb motor and cardiorespiratory function and increase the risk of injury occurrence. The main goal of this thesis was to investigate the influence of the covid-19 pandemic-induced break on physical fitness of young soccer players. Physical fitness level of athletes before and after the training cessation was measured with tests of speed by performing sprints of 5m, 10 m and 25 m, agility by performing the 20 yards test (20y), lower extremities explosiveness by performing countermovement jump (CMJ) and squat jump (SJ), and aerobic endurance by performing 30-15 Intermittent Fitness Test (30-15IFT). Statistically significant decreases occurred in sprint 5 m by 3,7% (1,07 ± 0,06 vs 1,11 ± 0,07, p < 0,001), 1,6% in sprint 10 m (1,82 ± 0,084 vs 1,85 ± 0,07, p < 0,01), 1,4% in sprint 25 m (3,7 ± 0,17 vs 3,75 ± 0,15, p < 0,01) and 3,5% in agility 20y (4,54 ± 0,21 vs 4,7 ± 0,28 p < 0,0001). In body mass, CMJ and 30-15IFT there was no statistically significant decreases in performance. The only test that showed significant increase in performance was the SJ, by 2,7% (31,4 ± 4,2 vs 32,26 ± 4,62, p = 0,03). Comparison of the given results with the previous research that used similar or equal periods of break shows smaller decrease of the measured abilities caused by covid-19 break compared to off-season breaks. Besides the strength exercises that most athletes execute regularly, it is important to implement speed, acceleration, sprint mechanics and change of direction drills in the off-season period, considering the decreases in performance are significant in variables that include horizontal explosiveness such as sprint, unlike the variables that manifest vertical explosiveness such as jumping.