Understanding Growth and Maturation

A summary of Peak Height Velocity, Biological Age and the Calculations Involved.

Maturation

Chronological age is the age of a person from birth, whereas maturation is a measure of biological age, the years from the onset of puberty.

There are a number of methods used to measure biological age, using both parental height or anthropometric data, in both cases using a prediction equation to establish Peak Height Velocity (PHV). PHV is deemed as the period of the most rapid growth during adolescence, usually associated towards the exit of puberty. Although there is an average age for both boys and girls for the onset of PHV, there is a wide range where individuals can either enter puberty and therefore hit PHV earlier or later by as much as 3 years difference. It is also essential to note that on average girls will enter puberty two years earlier than boys, which explains why girls usually outperform their male peers on the whole during the first few years of secondary school, before a more level playing ground is established thereafter.  

When is Peak Height Velocity occurring?

It's hard to pin point and exact moment during testing to say that an athlete is experiencing PHV, but you can track trends of growth. The speed of growth during PHV is typically around 10cm per year with a range of 5.5-13cm per year in males and 9cm per year average with a range of 5.1-11.2cm per year in females. 

Measuring every 3-4 months is standard practice, any shorter and you won't see much change, any longer and you may have missed key growth points to help forecast your athlete's maturity status. 

If you have access to parent heights that will unlock the ability to use the Khamis-Roche equation, where it predicts an athlete's potential max height. An athlete at 90-91% of their potential height is likely to be around their PHV.

What effect does PHV have?

During periods of rapid growth the brain requires a bit of retraining, limbs are now longer and aren't in the exact place the brain thinks it should be. It can cause coordination issues, particularly in skill sports and coaches may notice increase footwork and handling errors - miss-timed shots or bad catches for example.

1. Increased forces on the joints

a. Through longer lever lengths

b. Increased bodyweight from growth adding strain to the joints that muscles haven't adapted to.

2. Increased fatigue - growing requires a lot of energy, athletes may turn up fatigued for sessions after a poor nights sleep, being underfed as the body uses more energy during growth or hormones increasing the perception of fatigue. 

3. Increased stress - stress is not just being frustrated or overwhelmed about work or exams. Stress can be from these mental strains outlined above, designed stress which is incorporated into a training program - the body needs stress to adapt after all - and additional stress put on the body through lack of sleep, growth, commuting, homework and maybe even a part-time job. These all combine and during a period of peak growth that addition could be the breaking point towards an injury, limit the stress where possible during this period. 

What equipment do I need?

To use the Mirwald Equation you will need:

- An accurate method of measuring height, we use a Seca Stadiometer.

- An accurate measure of weight

- Seated height, if you are using a chair remember to measure the height of the chair and subtract it from the measured height

- The athlete's date of birth and the date of the test

To use the Khamis-Roche Equation:

You will need all of the above and the height of the athlete's mother and father.

What does MVP show?

MVP Analytics will show the Mirwald equation providing an estimate of the number of years until PHV or since PHV for that athlete. If parent height has been added to the athlete profile the Khamis-Roche results will display indicating potential height and the current percentage of that potential height.