What is the growth spurt?
PHV (Peak Height Velocity) is the moment during the adolescent growth spurt when height grows fastest. A child who grows ~5–6 cm a year through childhood briefly reaches a rate of up to 8–10 cm a year in this period. The spurt is the turning point at the heart of puberty, and over the following few years growth slows and ends as the growth plates close.
The timing of PHV depends on maturation, not calendar age. It occurs on average around age 11–12 in girls and 13–14 in boys; but in early- or late-developing children this age can shift markedly. Typically, at the moment of PHV the child has reached about 90% of their adult height.
Why does injury risk rise?
During the growth spurt, bones lengthen faster than muscles and tendons. This temporary mismatch reduces flexibility, impairs coordination (“adolescent awkwardness”) and leaves the areas near the growth plates open to strain. For this reason the circa-PHV (around the spurt) period is the window of highest injury risk, especially in sports involving jumping, sprinting and sudden changes of direction.
Common overuse problems in this period include Osgood-Schlatter below the knee and Sever’s disease at the heel. These are usually temporary but painful conditions and call for a temporary reduction in load.
Training during the spurt
The modern long-term athletic development (LTAD) approach recommends temporarily reducing total and impact (jumping/running) load by 10–20% during the growth spurt. Instead, the emphasis shifts to relearning movement quality at low load, and to balance and core control; because coordination has to be recalibrated alongside the lengthening limbs.
This “brake” does not slow development; on the contrary, it makes uninterrupted development possible by preventing injury. Once the spurt has passed and maturation has advanced (post-PHV), strength and power development can be safely accelerated. Measuring height every 1–3 months is a practical way to catch the onset of the spurt.
PHV and height prediction
Knowing where PHV is also makes sense of height prediction. A child before the spurt has significant growth ahead; a child past the peak of the spurt has relatively little growth remaining. So when assessed together with maturation indicators (bone age, %PAH), the question “how much more will this child grow?” can be answered far more reliably.
PHV timing can also be tracked familially: whether a parent developed early or late gives a clue about the timing of the child’s spurt.
Managing the spurt as a family
The growth spurt is an intense period not only physically but also emotionally. Adjusting to a rapidly changing body, temporary clumsiness, changes in appetite and sleep, and mood swings can all accompany this period. When families meet these changes not as a “problem” but as a natural part of development, the process is far easier for the child.
Practical areas of support are: supporting rapid growth with adequate and balanced nutrition; prioritising sleep (much of growth hormone is released during deep sleep); in children who play sport, temporarily reducing impact load and watching for knee and heel pain; and talking about the changes in the child’s body in a positive, non-embarrassing way. The spurt completes within a few years, and growth slows and ends.