Julio has run marathons all of his life, and recently has cut back on some of his other activities to increase the time he has for training in order to maintain his running skills. this is an example of

It is an example of selective optimization because it is a way of improving or practicing a particular thing in order to maintain healthy or to improve the person's health and his or her well being. It could be seen above as he tries to do everything he can, in a healthy way, in order to keep himself from doing and maintaining his skills.