If you’re a parent of teenagers, you already know this. If you were a teenager (we hope you were), you probably remember it. Puberty brings with it rapid, abrupt growth that makes wardrobes obsolete in just a few months, with some teens gaining more than ten centimeters in a year. However, is it really at this age that we grow the fastest?
You can imagine that if we ask ourselves the question, it is because we know that the answer is a little less simple than we thought. According to a scientific study published in the Journal of Adolescent Health and relayed by the online media Live Science, the adolescent growth spurt is in fact only the second fastest growth period in human life.
“We track the growth of children from birth to adulthood and the fastest period is clearly the early years, during infancy”reveals Sean Cumming, professor at the University of Bath (United Kingdom). At this stage, infants can grow twenty-five to thirty centimeters per year, more than double the rate of the most dramatic adolescent growth spurts. In girls, 50% of adult height is even reached by 18 months, compared to 24 months in boys, specifies Adam Baxter-Jones, professor at the University of Saskatchewan (Canada).
The influence of hormones
After this phase, growth begins to slow down. Between the ages of 4 and puberty, children gain on average five to six centimeters per year. The second fastest period of growth occurs at puberty. At the peak of this phase, girls grow an average of nine centimeters per year and boys about ten centimeters. However, these figures remain averages. “When we measure growth very regularly, we observe extremely intense peaks, sometimes close to twenty centimeters per year, followed by phases of adaptation of the body”underlines Sean Cumming.
As in early childhood, girls experience puberty earlier, around age 11, while boys begin it on average two years later. The latter generally have a stronger and longer growth spurt, in part due to higher production of growth hormone and testosterone. Growth associated with puberty ends around age 16 for girls and 18 for boys, which explains why they are, on average, taller as adults.
However, the age of puberty does not influence final height: late-maturing young grow longer. Growth spurts also change the silhouette. They start with the extremities (hands and feet), before reaching the arms and legs, then the torso. As the researchers explain, these periods of rapid growth also weaken the body. The bones lengthen before mineralizing, with a delay of approximately nine months, which increases the risk of fractures. Muscles and tendons also take time to adapt, which could lead to certain injuries.
Experts point out that strong variations in growth are normal and that adult height depends above all on genetics. Even in the rare cases of excessive growth linked to hormonal disorders, the rate remains lower than that observed in babies.
