The adolescent player will experience periods of fast somatic growth and biological maturation until adult height is reached in their mid-teenage years (girls) or late teenage years (boys). Growth takes place in a relatively predictable, stepwise manner, although maturation of physiological systems occurs at different times and rates between individuals. Chronological age is not a great indicator of maturity status, and often, a 14-year-old may be as tall and muscular as an individual quite a few years older or vice versa. Therefore, adolescents can be rated as biologically early, on time or late maturing. The adolescent growth spurt is considered to affect injury risk in sport, leaving players more susceptible to growth plate-related and overuse injuries (in particular stress fractures). A major challenge for any aspiring elite youth player is to train and play hard enough to reach performance potential but not so much that it would lead to repetitive injury.