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Use PHV to make better training decisions for your players
Peak Height Velocity measurements can reduce the number of assumptions you make about the current development stage of your players and help you help them with training programmes.
When working with youth players, we often hear phrases thrown around such as ‘growth spurts’ ‘early or late developers’ when referring to the stature of players.
Sometimes we will try to guess if a player has had a growth spurt or falls into an ‘early’ or ‘late’ development window.
This can lead to assumptions about how players will develop in later life. We might think a tall player will always be tall. Rather than relying on guesswork, one method for working out the relative maturity of a player is to calculate the peak height velocity (PHV) of a player.
WHAT IS PHV?
Peak height velocity is the time in which an adolescent has the fastest upward growth in their stature, that is their biggest ‘growth spurt’.
Girls will experience an earlier PHV compared to boys, but boys will grow more during this period.
We can calculate this major growth spurt by calculating the maturity offset (age of PHV) of our players with some easy to take measurements.
Calculating the PHV of a player is a fairly simple procedure. You will need:
- Date of birth
- Date of measurement
- Standing height (cm)
- Sitting height (cm)
- Weight (kg) – minimal clothing and shoes boots off to 0.1kg
Use a standard set of scales and a stadiometer to get all these measurements for a player.
To calculate sitting height, measure the height of a player sat on a stool (ensure you know the height of the stool) then subtract the height of the stool from the result of the sitting height.
For example, if a player has a 120cm sitting height on a 40cm high stool, their true sitting height is 80cm.
When you have all the relevant data, then you can work out the PHV by using an online calculator such as the one provided by the University of Saskatchewan. Ideally you will carry these measurements out 3 – 4 times a year.
WHY CALCULATE PHV
There are three reasons as to why we would want to work out when our players will hit their PHV and how it can help us to plan the development of our players:
1. Understand the future development of players
One of the most common misconceptions spreading in rugby is that early developers who are tall will eventually be caught up by shorter peers.
Whilst there may be some players who have an early PHV that go on to become an average height, it is also true the tall kids can go on to become tall adults.
By understanding where a player is in their maturity offset, we begin to understand what they will look like in maturation.
2. Accounting for changes in players
We know that players going through a growth spurt can lose some of the co-ordination they previously had as they develop.
Players also will have improved capacity for aerobic work on hitting PHV – so will naturally be able to run longer.
PHV also comes at a time of hormonal upheaval, so we may also see some attitude changes.
3. Adapting training to suit maturation status
We can tailor a training to a players biological age as opposed to their chronological age, which may prove beneficial. Research has shown that prior to PHV players respond well in a development sense to sprint training and simple plyometrics whereas after PHV players respon better to more strength training and challenging plyometrics.
Calculating the PHV of players gives us valuable insight into when players are likely to undergo a growth spurt and allows us to tailor training to suit the stages they are at.