I strongly agree with the above conclusion just because I have already run into some people who tried to manage training programs but failed before they cross the half of the road!
When you see a youngster doing some exercises on his/her own, you first perceive this as a magnificent step for the rest of the life of him/her. However, you will probably observe some problems with the exercise program; irregularities in the schedule, little care for mental health, etc. Unless it is advised by a therapist, it is very hard for all of us to decide the criteria our exercise program should depend on, and youngsters are those people who suffer most from such a problem.
Exercise programs can be analyzed in terms of person's needs and transformed into an optimum one for the highest efficiency taking into consideration the person's age, physical status, mental behavior manners, etc. Only after a careful examination of such routines can professionals agree on a profitable exercise plan, and the person taking this program seriously will probably get what s/he would like to have, at the end 🙂
I think most exercise programs fail because people get bored of them. In fact most gyms gamble on the fact that most of their members will only come for a few times and quit. That way they can make more money off more people with memberships without overcrowding their gym. I think it's important to find an activity that you enjoy doing and will stick with. This could be walking or riding your bike or even playing tennis. Do something you enjoy doing and there's a good chance you'll keep doing it.