Adolescent Growth Spurts

What drives the growth spurt

Puberty begins when the brain releases hormones that trigger the ovaries or testes to produce estrogen or testosterone. These sex hormones, together with growth hormone, make the growth plates at the ends of long bones grow rapidly. Later, estrogen (in both sexes) makes the growth plates close, ending height growth.

Timing and how much teens grow

Boys end up taller on average mainly because they have about two extra years of childhood growth before the spurt and a slightly greater peak.

The feet and hands grow first, then the arms and legs, then the trunk, which is why teens can look gangly for a while. Shoulders widen in boys and hips widen in girls.

Signs of a growth spurt

• clothes and shoes becoming too small quickly
• a big increase in appetite
• needing more sleep and feeling tired
• temporary clumsiness as the brain adjusts to longer limbs
• aching legs, knees or heels
• stretch marks on the hips, thighs, back or breasts
• other puberty changes: body hair, acne, voice changes in boys, breast development and periods in girls

Aches and conditions linked to growth spurts

Growing pains

Growing pains are aching in both legs, usually the shins, calves or behind the knees, in the evening or at night. They are gone by morning, do not cause a limp and are common in younger children as well as early teens. Despite the name, they are not caused by bone growth itself.

Osgood-Schlatter disease

Osgood-Schlatter disease causes a painful bump below the kneecap, where the patellar tendon pulls on a growth area of the shin. It is common in active teens during growth spurts, especially in running and jumping sports, and settles when growth finishes.

Sever's disease

A similar problem at the heel, where the Achilles tendon pulls on the heel's growth plate. It causes heel pain with running, typically in children aged 8 to 14.

Scoliosis

Adolescent idiopathic scoliosis can worsen quickly during a growth spurt. Uneven shoulders, an uneven waist or a rib hump on bending forward should be checked.

Slipped capital femoral epiphysis (SCFE)

The top of the thigh bone slips at the growth plate, usually in early teens and more often in overweight boys. It causes a limp with hip, thigh or knee pain and needs urgent treatment.

Tight muscles and flexibility

Bones can grow faster than muscles and tendons lengthen, causing tightness in the hamstrings and calves and a higher risk of strains.

Supporting healthy growth

• Nutrition: enough calories, protein, calcium (about 1,300 mg a day for ages 9 to 18) and vitamin D. Dairy or fortified alternatives, leafy greens and beans help.
• Sleep: teens need 8 to 10 hours a night. Growth hormone is released mainly during deep sleep.
• Exercise: weight-bearing activity builds bone density, which peaks in the late teens and early 20s.
• Avoid smoking, alcohol and anabolic steroids, which can harm bone growth.

Height is mainly determined by genetics. Supplements and stretching programs do not increase final height in healthy teens.

When growth needs a doctor's check

Pediatricians plot height and weight on growth charts at regular visits. Further assessment is recommended for:

• early puberty: signs before 8 in girls or 9 in boys (early puberty)
• late puberty: no signs by 13 in girls or 14 in boys
• height well below what is expected from the parents' heights
• growth slowing or crossing down percentile lines
• very rapid growth with headaches, vision changes or unusual features

A doctor may order a bone age X-ray of the hand, blood tests (thyroid, growth hormone markers, sex hormones) and sometimes a brain MRI. Many late-developing teens have constitutional delay of growth and puberty, a normal variant that often runs in families. They start late but catch up.

Frequently asked questions

At what age do growth spurts happen in teens?

Girls usually have their growth spurt between ages 10 and 14, peaking around 11 to 12. Boys usually start later, between 12 and 16, peaking around 13 to 14. The exact timing varies widely and is often similar to a parent's.

How much do you grow during a growth spurt?

At the peak, girls grow about 8 cm (3 inches) a year and boys about 9 to 10 cm (around 4 inches) a year. Over the whole of puberty, girls gain about 20 to 25 cm (8 to 10 inches) and boys about 25 to 30 cm (10 to 12 inches).

What are the signs of a growth spurt?

Signs include rapidly outgrowing clothes and shoes, a big appetite, more tiredness, clumsiness, aching legs or knees, and stretch marks. They come along with other puberty changes such as body hair, acne, breast development or voice changes.

Can a growth spurt cause knee pain?

Yes. Growth spurts commonly cause knee pain, especially Osgood-Schlatter disease, a painful bump below the kneecap in active teens. Pain usually eases with rest, ice and stretching. A limp or pain in the hip or thigh needs prompt assessment.

When do girls and boys stop growing?

Most girls stop growing around 14 to 16, usually about 2 years after their first period. Most boys stop around 16 to 18, though some grow a little into their late teens or early 20s. Growth ends when the growth plates close.