Calculate growth spurt

Calculate growth spurt of a child is based on the following data:

  1. Date of birth
  2. Test date
  3. Gender
  4. Length
  5. Sitting height
  6. Weight

These parameters are translated using a mathematical formula to the age at which the child is at the top of the growth spurt. This age is called the APHV or Age at Peak Height Velocity and represents the number of years before or after the PHV (Peak Height Velocity).

In particular, the seat height, which is measured from the ischium to the crown, is very important for the formula.

Enter the data

On entering the data, we can determine the growth phase a particular child is in and calculate growth spurt.


The result of the calculation of the most recent measurement can then be viewed in a dashboard. The previous measurements are also accessible as an archive.


The results and analysis of the measurements helps the trainer to prevent log-term injuries and create tailormade training based on the biological age of the child:

  1. In which adolescent / growth phase is the child?
  2. What is the biological age?
  3. When does the growth spurt start?
  4. When is the peak of the growth spurt?
  5. What can and what cannot you train in this phase?
  6. Is the child a precocious or late bloomer?
  7. A timeline per child with an overview of all growth phases
  8. A timeline with growth phases of all children in 1 overview

Training around the growth spurt

One can distinguish three periods around the growth spurt and which are important in training of adolescents. These phases are irrespective of precocious, average-and late-maturing children.The ASM focuses on using the phases P1, P2 and P3. This phase model (initiated by the authors, see Figure 3.7) has been used at the Dutch football club AFC Ajax for many years when implementing the ASM.

The teams U9 to U16 train on a differentiated basis using the PHV determination as described above. The different phases have different training schemes, and this is a good start to tailor the training.The full P-phase takes 4 years. Is it possible to educate children without using these three phases? Of course it is, but phasing this crucial stage of a child’s development creates a structure that can be used to arrange the (development-specific) exercises.

3 growth phases

Proponents of the ASM are well aware of the simplification of this phase model and the complexity of human development. However, experiential knowledge has taught that this approach is practical and manageable. The phases are:

  • P1 The pre-adolescent period: This period starts a year before the start of the accelerated length growth (the onset).
  • P2 The adolescent period:Boys: from the onset to an average of three months after the APHV (= the PWV). So 0.2–0.4 years after the APHV = total of 1.3 years.Girls: from the onset to an average of six months after the APHV (= the PWV). So 0.3–0.9 years after the APHV = total of 1.6 years.
  • P3 The post-adolescent period:Boys: from two to four months after the APHV to 1.7 years later.Girls: from three to nine months after the APHV to 1.4 years later.


growth spurt calculate