Development of Muscle Function in Prepubertal Children As a Response to Growth and Resistance Training

Healthy skeletal muscle development is crucial for a life-long quality of life. Childhood and puberty may be key periods for developing muscle growth and neuromuscular capacities, which are essential for bone-muscle interaction, metabolism, and participation in various sports. Even though the central role of physical activity in healthy physical development is well recognized, the decline in muscular fitness in today's children is alarming. This can lead to lasting deficits in muscle development and have a negative impact on overall health. Well-designed resistance training (RT) could address this problem, since it has an effective positive impact on muscular strength, bone density, metabolism, and spontaneous physical activity especially in childhood. In general, muscles adapt according to physical activity stimuli. However, children show different responses to exercise and training. The physiologic differences, which are reflected in lower neuromuscular capacities and hormonal responses, but also in a better resistance to fatigue than in adults, are not yet fully understood. It is well established, that RT in children is safe, effective and has multiple benefits for health. However, the underlying mechanisms that lead to increased muscle strength are unclear and it is unknown how sustainable these are. Today's common conception is that increased muscular strength is predominantly caused by neural adaptations and changes in muscle morphology due to lower androgenic responses are negligible. Although higher neuromuscular adaptation potential is evident, it is still not sufficient to explain all strength increases, suggesting that additional mechanisms are involved in the process. Most studies are outdated, had methodological and statistical limitations, and many state-of-the-art methods have not yet been applied to children, hence, there is a need for a comprehensive, in-depth investigation to understand muscle adaptations to training and growth in children. With