The Russians believed that there is a finite period of about 8-10 years where an individual can reach their genetic potential for performance. Because of that, when they did their recruiting into their athletic programs they took the kids they believed were capable of becoming national level athletes and they began their training around the ages of 10 and intensivied their training in their early teens. These athletes would then reach their peak performances in their late teens and then be finished with competition. The athletes they selected for Olympic level competition they did much less training with at young ages until about the age of 14 when they would then begin their intensive athletic development. They believed by waiting until the athletes were older to begin their intensive training programs they would be able to maximize their development and reach their peak performances in their early to mid 20s, which is when they believed phyiologically speaking the human body is primed to perform at the highest levels. Their overall philosophy in general is that you should wait until the body is able to maximally respond and adapt before you use the most intense methods. If you use more intense methods at younger ages they will not be as effective when utilized later in life. This is the same principle that conjugated loading was developed around by Verkhoshansky. You systematically replace the means and methods with more intense ones as each one starts to lose its effectiveness. This is a very intelligent and well thought out philosophy of training children and athletes in general and has worked very well for the russians and eastern europeans for a long time.