PHV: why biological maturation changes the way we read test results

Two children of the same age, in the same team, can be as much as three or four years apart biologically. Judge them by the same yardstick and one looks like a “talent” while the other looks “unremarkable” — when in reality we are simply looking at two different stages of development. This is where PHV comes in.

What PHV is

PHV (Peak Height Velocity) is the period in which a child grows taller at the fastest rate — the peak of the adolescent growth “sprint”. In girls it usually appears earlier than in boys, but exactly when it happens varies widely from one child to the next (Malina, Bouchard & Bar-Or 2004). PHV works as a biological landmark: it lets us place every athlete on a maturation axis — before, at, or after the growth spurt — regardless of what their ID card says.

The growth spurt changes everything — temporarily

Around PHV the body changes fast: the limbs lengthen before neuromuscular control has time to adapt, the centre of mass shifts, and the strength-to-body-mass ratio is disrupted. That is why it is entirely normal for a young athlete in the middle of a growth spurt to look temporarily more awkward, to stall in jumping or to lose coordination — none of which says anything about their long-term prospects. It is also a period of increased load on tendons and growth plates, which matters for how training is designed.

Why comparison by chronological age is unfair

Most norms and most academy “standards” are organised by year of birth. Yet at 13–14 years of age, an early-maturing athlete can hold a substantial advantage in strength, speed and muscle mass over a late-maturing peer of the same age. The result is unfair in both directions:

• The early maturer is overrated — good numbers get credited to talent, when in part they simply reflect having matured sooner.
• The late maturer is underrated — and often loses squad places, playing time or even motivation, right before their own growth arrives.

International experience in talent development shows that many late maturers, once maturation is complete, catch up with and overtake the early ones. The point is not to lose them along the way because they were judged by the wrong yardstick.

How we assess biological maturation

No invasive methods are needed. Using simple anthropometric measurements — standing height, sitting height, body mass — together with the child’s age, we apply established “maturity offset” prediction equations (Mirwald et al. 2002), which estimate the distance from PHV (how many years before or after peak growth the athlete currently is). With repeated height measurements at regular intervals, growth rate is tracked and the growth-spurt “window” is identified with good accuracy.

How we factor it into the norms

On our platform, young athletes’ results are not read against chronological age alone. Each athlete’s maturation profile accompanies their tests, so that coaches and parents see performance in the right context: an “average” jump from an athlete who has not yet passed PHV may be excellent for their stage of development. Assessment therefore focuses on individual progress from test to test — which is also the fairest comparison of all: the athlete against their own previous self.

What this means for parents and coaches

• Do not judge by age group alone — ask where the athlete stands in relation to PHV.
• Expect temporary dips in coordination and performance during the growth spurt; they are normal and short-lived.
• Adjust the training load through the period of rapid growth — fewer repeated jumps and impacts, more technique and movement control. Modern models of long-term athletic development for young athletes recommend exactly this: training content that follows the stage of maturation and not simply age (Lloyd & Oliver 2012).
• Re-test at regular intervals: it is the only way to tell genuine progress apart from maturation.

References

• Mirwald RL, Baxter-Jones ADG, Bailey DA, Beunen GP (2002). An assessment of maturity from anthropometric measurements. Medicine & Science in Sports & Exercise.
• Malina RM, Bouchard C, Bar-Or O (2004). Growth, Maturation, and Physical Activity. 2nd ed. Human Kinetics.
• Lloyd RS, Oliver JL (2012). The Youth Physical Development model: a new approach to long-term athletic development. Strength and Conditioning Journal.