ABSTRACT
During the latest decade the focus on sport for children has increased and so have public and scientific interests in training effects during childhood and adolescence. In studies concerning training effects on children and adolescents the assessment of pubertal maturation has been made from a variety of parameters such as chronological age, bone age, peak height velocity, Tanner stages, serum testosterone, age of menarche and testicular volume. However, one cannot be sure that these indicators measure the same kind of biological maturity nor that they have the same timing of appearance, although a high correlation is seen across studies[1]. In adults, substantial information about factors which determine strength and the trainability of strength is available[e.g. 2, 3], It has been suggested from early studies that prepubescent boys were incapable of increasing strength or muscle cross-sectional area[4]. Insufficient quantities of circulating androgens have been suggested as a rationale for the ineffectiveness of strength training in prepubertal boys[4], A number of more recent studies have shown strength gains in prepubescent children following appropriate resistance training programmes[5, 6], Strength is related to body size and muscle mass but it increases more than predicted from height alone[7].
