Notes · Maturation
Why a young athlete gets less coordinated during a growth spurt
A player who was competent six months ago now looks heavy and mistimed. In most cases nothing has been lost. The limbs have changed length faster than the control of them has been recalibrated.
A common presentation at intake is a young player, usually between eleven and fourteen, whose coach or parent reports that their movement has deteriorated. They describe a player who was technically sound the previous season and who now mistimes contacts, lands heavily, and appears slower despite training as much as before. The concern raised is usually that the athlete has stopped applying themselves.
A more likely explanation is maturational. During the period around peak height velocity, the segments of the limbs lengthen rapidly. The nervous system's model of where those segments are, and how much force is required to move them, was calibrated against the previous dimensions. Until it is recalibrated, timing and coordination can be disrupted. The evidence for this is mixed and it is offered here as a common coaching observation.
What this changes in practice
Three adjustments follow. The first is that technical correction during this period has a lower yield than it does on either side of it, because the target is moving. The second is that landing and deceleration exposure warrants closer attention, since the athlete is managing greater mass through joints whose control has been disrupted. The third is that the athlete's own account matters: a player who believes they are getting worse will often reduce effort to avoid visible failure, and that reduction is frequently mistaken for the original problem.
How it is handled here
Athletes are assigned a maturity band at assessment, and prescription is written against the band. Through the circa-PHV period the emphasis moves toward controlled volume, landing mechanics, and preserving the athlete's confidence in their own body, and away from maximal expression and fine technical work. Testing is repeated on a shorter interval, because the athlete's physical profile is changing faster than it will at any other point in their development.
Where a parent or coach has been told that a player has plateaued, it is worth establishing where that player sits in relation to peak height velocity before drawing any conclusion about their trajectory.
Scope of practice JMP Sports Inc. provides physical assessment, training, and athletic preparation. It is not a regulated health profession, does not diagnose or treat injury or illness, and nothing here is medical advice. Anyone with a current injury, a medical condition, or a clinician's restriction should consult their physician or physiotherapist; programming is carried out in coordination with them.