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more about growth spurts
from
the BBC
Regular trips to the shoe shop and trousers that rapidly
become too short are common occurrences during puberty.
In their teens, children put on an amazing growth spurt
to reach their final adult height. At their fastest, boys can grow taller
by as much as 9cm a year and girls at a rate of 8cm a year. It's no wonder
teenagers are clumsy. Their body is shooting upwards at a speed their
brain simply cannot keep up with.
Outside-in
This phenomenal growth starts at the outside of the body
and works in. Hands and feet are the first to expand. Needing new shoes is
the first sign of trouble.
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teenagers shoot up so fast that their
brains can't keep up |
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Next, arms and legs grow longer, and even here the
'outside-in' rule applies. The shin bones lengthen before the thigh, and
the forearm before the upper arm.
Finally the spine grows. The very last expansion is a
broadening of the chest and shoulders in boys, and a widening of the hips
and pelvis in girls.
Growing up and tripping over
Many teenagers shoot up so fast that their brains cannot
keep up. As their height increases, their centre of gravity lifts. This
happens so quickly that the brain does not get a chance to calculate the
new rules for balancing. Clumsiness is often unavoidable.
The trigger
Rapidly increasing height is a sign that a teenager is
experiencing puberty. Growth is triggered in both boys and girls by
increased levels of the sex hormone testosterone. This chemical also
triggers the sexual organs to develop. In fact, the relationship between
growth of the skeleton and puberty is so strong that a teenager's
developmental age can be measured by looking at the maturity of the bones
in their hand and wrist.
Perfect timing?
Timing is everything. No teenager wants to be developing
too quickly, or lagging behind. In reality, many of them grow up much
earlier or later than the average and this is perfectly normal.
The average
boy is growing fastest between 14 and 15.
Girls start earlier, growing fastest when 12 and 13. Girls also end
their growth spurt earlier at 18, while boys need another two years before
they finish growing aged 20. |