The main objective of this study was to analyze the change in physical conditioning after an eight-week training program based on interval training 4x4 minutes which contained movements in different modality of locomotion and different speed of movement (from 6km/h to 9km/h). This type of training was integrated in standard duration of the training. The sample was conducted from eleven football players of younger age categories U13 (n=11, age 12,6±4,52, height 156,25±4,52, weight 43,78±5,27). Each participant was measured in twenty anthropometric variables, eight variables for the assessment of motor abilities and one variable for estimation of aerobic capacity. The test was conducted in two time points, before the implementation of the interval type of training (initial testing) and after eight weeks of training (final testing). Statistically significant difference in anthropometric variables was observed for variables ALVT (0,76%), ALRR (1,42%), ALDN-L (2,88%), AVONAT (-1,81%) and ANPOT (27,01%). In variables of motor abilities, statistically significant difference was realized in variables MESAR1 (11,28%) and MESSDM (12,30%). In the test for aerobic capacity there is a statistically significant difference and the progress of 20,25% in regards to initial testing. The changes in anthropometric variables we can attribute to biological growth and development because the tested population, at this time, is in the phase of the growth spurt Unlike anthropometric variables, in variables for evaluation of explosive-strength and variables for evaluation aerobic energetic capacity, the subjects accomplished significant improvement. These results can serve football coaches for planning and programming training work during the season.