Research published in Nature Scientific Reports explains that the adolescent growth spurt is highly standardized, typically peaking when a child reaches 90% of their final adult height .
The adolescent growth spurt of boys and girls of the ... - PubMed leggy teen
This classic PubMed paper details how leg length reaches its peak velocity earlier than the trunk (sitting height). It notes that while girls experience this earlier (around age 10-11), boys' leg lengths typically exceed girls' by age 12. leggy teen
Several scientific papers and reviews cover this phenomenon: Biological and Growth Pattern Studies leggy teen