Football is the most popular sport in the world and also the most important sideline in the world. The global popularity of this sport affects many children because the vast majority of children want to play football. The limits of the start of training move from year to year, so we already have cases where numerous clubs accept small children at the age of 4. Starting sports this early brings numerous challenges for both children and coaches. Care should be taken that children do not go to early specialization before the time, so that burnout does not occur. Many trainers fall into this kind of trap, therefore the training should be well planned and programmed, not just for one microcycle but for the complete development of the child through the growing procces. Of course, it is not possible to determine exactly how and what should be trained, but the basis of what is most suitable for a certain age would be followed. Many serious sports clubs have a fitness coach in addition to the head coach, and this naturally makes the job easier for the head coach, who can only focus on the football development of the children. In this paper, I will write about fitness training for younger age categories (U8, U9, U10). The goal of the fitness coach at this age is proper and gradual development of motor skills. The goal is also to monitor the growth and development of children and to spot problems in time and react in time. The problems faced by trainers are irregular growth and development (scoliosis, kyphosis, flat feet, winged shoulder blades...). If the coaches do not react in time, the child may have health problems at a later age and the risk of injury in the later phase of growing up increases. Training for children should be fun and meaningful, but not long-lasting. Children learn best through games, so we simply need to be creative and develop their abilities in such a way. Training should not be specialized, but in this initial phase (pre-puberty) should be aimed at multifaceted development.