By Simon Webb
One of the key elements in applying LTAD principles to physical activities and sport programs is recognizing that an athlete’s chronological age does not necessarily reflect their developmental age – physically or mentally. Children’s bodies mature at different rates therefore their developmental age should determine the way they train and practice in their sport.
One of the greatest problems for junior development in sport is that junior athletes, especially adolescents, are grouped together based on their chronological age and coaches tend to train them the same. Research has shown that chronological age is not a good indicator on which to base junior development models for athletes between the ages of 10 to 16.
There is a wide variation in the physical, cognitive and emotional development of athletes within this age group. One practical solution is to use the onset of Peak Height Velocity (PHV) – commonly referred to as their growth spurt. Peak Height Velocity refers to the maximum rate of growth in stature during the adolescent growth spurt. It can be used as a reference point for the design of individual programs with relation to “critical” or “sensitive” periods of trainability during the maturation process.
Prior to the onset of PHV, boys and girls can train together and chronological age can be used to determine training and competition programs. The average age of the onset of PHV is 12 in females and 14 for males and is influenced by both genetic and environmental factors including climate, cultural influences and social environment.
For both boys and girls aged 10-16, the sequence of developmental events in adolescence can occur 2 or more years earlier or later than average. For example you could have two 12 year olds in a program. One is two years ahead in their maturation and appears to be more like 14 year olds, the other is two years behind and appears to be more like a 10 year old developmentally. Essentially this means an early developing child may have as much as a four to five year physiological advantage over their late maturing peers.
Early maturers initially have a physical size advantage and often perform better than late maturers. These individuals experience more early success due to physical advantage and not necessarily enhanced skill or abilities. Conversely, late maturers experience failure and frustration because they are physically behind their same age peers and some drop out because of a lack of early performance success, or worse, because they are cut from the team.
Adolescent awkwardness, due to the rapid physical growth, affects performance especially for early maturers. Late Maturers often catch up to or exceed the performance of early maturers but only if they have stayed in their sport. Research in tracking the “outstanding” performers in elementary school found that only 25% remained outstanding in later years, suggesting early success does not predict later success.
The onset of PHV is a reference point that provides valuable information for training athletes’ energy systems and the central nervous system regardless of chronological age. Using simple measurements, PHV can be monitored and training can be related and optimized to exploit the critical periods of trainability. This approach can enhance the development of short and long term individually optimized training, competition and recovery programs such as the optimal window for the accelerated adaptation to stamina (endurance), strength, speed, skill and suppleness (flexibility) training. These are also referred to as the Five S’s of training and performance.
LTAD requires the identification of early, average and late developers in order to help design appropriate training and competition programs in relation to optimal trainability and readiness. The beginning of the growth spurt and the peak of the growth spurt are very significant in the LTAD applications to training and competition design.
All coaches should be monitoring PHV in their athletes. By initially recording and then constantly monitoring PHV parents, coaches and instructors can track the growth and physical maturation process in their athletes with whom they work with. To do this effectively, regular anthropometric monitoring of standing height, sitting height and arm length is required. Recommended frequency of measurement is every 3 months. In order to effectively monitor the rate of change, it is very important the frequency of measurement is consistent and started at an early enough age to identify important PHV changes at prepubescent ages. Experts recommend that all measurements be taken in the morning and at a similar time to accommodate seasonal variations and for consistency purposes. Measurements are more reliable taken after a rest day.
When to start Recording:
Step 1 – The earliest recommended age for a coach or parent to start measuring the height of their athletes is 6 years old or as soon as the coach has access to them in their program. Height measurements should continue at three monthly intervals (four times within a year).
How To Record PHV:
Step 2 – The easiest way for parents and coaches to monitor PHV is by measuring standing height. Have the junior athlete stand against a wall in bare feet. Make sure their ankles are together and legs are straight. Their heels, bottom, shoulder blades and head all need to be touching the wall. Eyes are looking straight ahead. Finally height is measured with a level ruler from the top of the head.
Step 3 - Create a chart or spreadsheet with height on the vertical axis and age on the horizontal axis. To begin, take one measurement and wait for three months to take the next. For example:
Jan 1: 129.5cm
Apr 1: 131cm
Use the latest measure and minus the previous measurement from it.
Apr 1: 131cm – Jan 1: 129.5cm = 1.5cm
As you continue to take the measurements every three months (which will be four times in a year) the growth velocity for this period for example would be 1.5 x 4 = 6cm per year.
Step 4 - As soon as the coach/parent notices a small deceleration in growth followed by acceleration in growth, it is highly recommend that the athletes training should be adapted accordingly to the optimal “windows of trainability”. (This article will be added to the website shortly).
Step 5 - PHV is the highest point of growth acceleration. After PHV is attained, a deceleration in growth will occur. Continue to monitor growth for at least 2 years after PHV, as training will still need to be adjusted to match the “critical” periods of trainability in that time.
The growth spurt can last anywhere from 1.5 years (for fast developers) to 5 years (for slow developers). For females the average growth rate is 6cm in the first year of the growth sport followed 8cm in the second year and 6cm in the third year. For boys, the average is slightly higher at 8cm in their first year of the growth spurt then 10cm in the second year followed by 8 in the third.
The two diagrams below show the average change in height for girls (figure 1) and boys (figure 2) in their growth velocities from age 2 through to 20 years old
Figures 1 & 2 taken from the RCGA Long Term Player Development Guide for Golf in Canada, pg11
Please continue to follow this website over the coming months as we will give you advice on what exercises to use and when to implement them during the critical periods in a junior athlete’s development to achieve the best possible results.