When I was 15 I sent for one of those Charles Atlas Body Buiilding Courses
All "Canadian Airforce Exercises" etc ~ Load of bollix.
Went into the RAF a few months later (aged 15 and half). 3 Square meals a day and loads of Square Bashing, PE etc and by the time I was 16 I had grown 3 inches taller and gained 2 stone of pure muscle. Parents didn't know me when I went home on my first leave. Head and shoulders above me Dad.