Now the ideas presented in this module are quite complex and indeed, they are also controversial. Yet they are very, very important. Understanding the neuro basis of critical or sensitive periods of brain development, provides insights into strategies for long term athlete development. Learning is possible throughout life but there appears to be an advantage to an athletes who has the neural circuits that were correctly laid down during early movement experiences. So with respect to this, here's a summary of the key points. First, during a child's development there appears to be periods of heightened brain plasticity. And these are called critical and sensitive periods. A critical period is the time when environmental input is required for proper development of the particular brain circuit. And if the brain is left unstimulated theory states, that the brain function served by that circuit will be permanently compromised. A sensitivity period on the other hand, is the time when the environmental experiences have the greatest impact on brain circuitry. And these circuits can be shaped by experiences later in life but to a lesser degree than occurs. If the experiences are provided within the sensitive period earlier in life. Point number three, failure to exploit the Windows of opportunity with the appropriate training stimuli could prevent the young athlete from reaching their genetic ceiling. Or at the very least make it more difficult for them to reach their genetic ceiling. And point number four, undertaking the correct training during the Window of opportunity has two possible affects. It could optimize the athletes genetic potential, and remember you can't go above genetic potential but it can optimize it. Or it may allow them to reach their genetic ceiling at a younger age. And point number five, the sensitivity periods to be linear in nature, with the more complex motor abilities reflecting prior experiences during sensitive periods. And point number six, aggressive training during the times when the body needs the resources for growth and maturation could permanently affect the natural biology of the child. The side affects of performance enhancing drugs though, suggests that growing the body faster is not always there. In fact, it can be detrimental and we need to tread with care when trying to accelerate a young athletes performance during the sensitivity windows until we know much more about the consequences of doing this and the researchers available. Now coming up next, we will examine the long term athlete development model. And this model has been adopted by sport governing bodies throughout the world and is the guiding framework for sports training and competition. From infancy, all the way through to adulthood and into the senior years. And there are four broad philosophical principals. Underlying the long term athlete development module. There is enjoyment, the principal of enjoyment. There is the striving for improvement. That's all the principal of striving for improvement. There's the principle of appropriate training and finally there's the principle of doing no harm.