What are PAH and %PAH?
PAH (Projected Adult Height) is an estimate of the adult height a child is expected to reach; it can be calculated with methods such as mid-parental, Khamis-Roche or Bayley-Pinneau. %PAH is a practical indicator derived from it: it tells you what percentage of the projected adult height the child’s current height has reached. For example, a child with a %PAH of 88% has reached about 88% of their adult height; they still have roughly 12% of growth ahead.
%PAH is a powerful and radiation-free way to understand maturation, because it directly measures how far the child has come on their growth journey.
%PAH as a maturation band
%PAH is used to place a child into maturation bands. The generally accepted thresholds are: below 85% is pre-PHV (before the growth spurt), 85–95% is circa-PHV (around the spurt) and above 95% is post-PHV (after the spurt). The peak of the growth spurt (PHV) usually corresponds to about 90% of adult height.
These bands are especially critical in sport. A child in the circa-PHV band is in the window where injury risk is highest; training load is adjusted accordingly. The bands also provide the basis for bio-banding (grouping by maturity).
Why is it useful?
The greatest advantage of %PAH is that it gives a concrete indicator of maturation without a bone-age X-ray. Because it can be calculated in any child with height and parental data, it makes it practical to estimate maturation in large groups (schools, clubs).
That said, %PAH is an estimate and depends on the accuracy of the projected adult height. The soundest use is to interpret %PAH together with growth velocity and, where needed, bone age. The platform uses %PAH as a context indicator in sport-readiness and maturation assessments.
Making decisions with %PAH in sport
The %PAH bands can be turned into concrete decisions in youth sport. In a child in the pre-PHV band (below 85%) the emphasis shifts to skill learning and play; in the circa-PHV band (85–95%) to load management and movement quality in order to reduce injury risk; and in the post-PHV band (above 95%) to gradual strength and power development. Because two children of the same age can be in different bands, this approach personalises training to true maturity rather than calendar age.
%PAH also provides a practical criterion for maturity-based grouping (bio-banding); having children in similar bands compete together improves both fairness and safety. Even so, %PAH is an estimate and depends on the accuracy of the projected adult height; it should not be used on its own as a “talent” or “suitability” label. The soundest use is to treat %PAH, together with growth velocity and observation, as a developmental guide.