Personal training started with body builders, and it ignited a brand new level of health consciousness in society. The original creator of the first modern health club was a gentleman named Jack LaLanne. He opened the club and worked as a personal trainer in 1936, according to his official website.
The Jack LaLanne websites details how Jack was a very interesting man for his time. As a young kid he was very unhealthy and loved sugary foods and other junk food. After attending a lecture in his teenage years everything changed: Jack became very, health conscious and studied all things health-related, including the best way to exercise your muscles.
He knew he was on to something, and he decided to not only help himself, but to help the world as well. He open the first gym that welcomed everyone, not just weight trainers and Olympic athletes. He developed the first real workout and personal training system, almost 40 years before anyone else.