Peak Height Velocity
What is PHV?
Peak Height Velocity (PHV) is essentially a child's most accelerated growth spurt and usually coincides with the onset of puberty. Females appear to experience the onset of this slightly earlier than males, with an average of 11 years for females and 13 for males. Males however tend to grow more during this period. It is our job to constantly monitor this using different testing methods and calculations such as maturity offset which can calculate a child's predicted age of PHV. This can help with prescribing and adapting training programmes. This is a vital aspect of a child's development and one which needs to be constantly monitored in order to enhance athleticism and performance both safely and effectively.
Youth Athlete - Physical Impact
Firstly, during PHV we are effectively asking a child to coordinate a larger, longer & heavier frame. Unsurprisingly, injury risk has been shown to spike dramatically during this time. Secondly, coordination of a 'skilled movement' (squat, tennis serve, football kick, cricket bowl etc) can sometimes be thrown out of the window. This is why PHV is often called ‘adolescence awkwardness.’
Kids also develop hormonal profiles that support increased muscle mass, and as a result, even without training, will naturally get stronger, jump higher, run faster etc. On the surface, this might seem like a positive, however without subsequent improvements in mechanical & movement technique and efficiency, you now have a child, who has more gears and a bigger engine, but cannot effectively steer and drive. They are now in charge of a heavier and longer body but have less efficient and poorer movement technique. Even the same training load will place more stress on them as a result.
Consider the following two scenarios.
Your child learning to drive efficiently a smaller, less powerful vehicle before eventually having to transition into controlling a larger, more powerful vehicle.
Your child going from zero driving experience to starting to learn in a larger, more powerful vehicle whilst on the highway at 110kph!
If your child has not been taught effective movement technique, such as how to jump & land, before puberty, when they encounter PHV, you are effectively starting their driving lessons at 110kph on the highway, hoping they don't crash and burn.
Youth Athlete - Mental Impact
Without an understanding or assessment of PHV, youth athletes can find themselves easily frustrated by performance loss, whether it be a result of simply being heavier, 'adolescent awkwardness', or as a result of being injured due to inadvertent increases in their workload. A dip in performance is natural at this stage and the athlete might find themselves losing matches which they had previously been expected to win, or struggle with tasks which they had found easy before. This can easily be misread as a lack of fitness or drop in work ethic, when it's actually quite the opposite.
Scenario we have seen before...
It's pre-season so the coach innocently decides it's time to up the volume of work being done. Your child is going through PHV and is now someone who is longer, heavier and without any additional increases in strength or power, certainly slower. Inevitably, your child’s performance will be worse, which the coach interprets as a loss of fitness compared to previous years/seasons. As a result, the coach insists your child must train even harder to regain the form they displayed last year. A RECIPE FOR DISASTER
What can we do?
For a start, we assess rather than guess, measuring PHV every 3 months as well as other key metrics such as strength, power and movement technique. This allows for individual workloads which will reduce injury risk.
The most important factor is ensuring every junior develops a foundation of quality movement before they go through their growth spurt. Re-learning movement patterns they have previously developed with a smaller, lighter, and more coordinated body, is much easier than trying to learn whilst during PHV.
The next point we focus on is developing strength to help maintain power to weight ratio as a child grows, a key metric in both explosive and endurance sports. Without appropriate increases in strength, both power to weight ratio and VO2 max (the body's ability to utilise oxygen per kilo of bodyweight) tend to decline when a child experiences PHV. Not only this, strength training can also reduce the risk of overuse injuries.
Written By Bryce Hounsome
