personal trainer and a physical therapist?

To become a PT, you must first complete the prerequisite courses that are required for entrance into the graduate program. This usually involves a lot of college level sciences and math. Many programs require you to complete a BS before entering the professional phase. In all, most programs are designed to be completed over a total of 6-7 years and result in either master's or doctorate level degree.

To become a personal trainer, you can do that in a matter of weeks...even by correspondance course and then sitting for an exam.

The scope of your knowlege will be much deeper as a physical therapist as you will focus on the disease/injury model.

A physical therapist's training and education is far more extensive and expansive than a personal trainer. A personal trainer is really nothing more than a private coach. An experienced personal trainer should be well versed in the anatomy and bio-mechanics involved in the activity in which they are training you. However, a personal trainer who is ALSO a physical therapist could apply that extensive knowledge of anatomy and physiology to achieve optimum results in the safest possible manner. As well as spot the early warning signs of injury long before a mere personal trainer ever could.

It's more difficult, and more rigorous, to become a physical therapist than a personal trainer. In fact, the term "personal trainer" is pretty vague and undefined. What you will find is that some physical therapists, especially those involved in sports-related areas, add on an ATC credential--athletic trainer. And the ATC is a focused, worthwhile credential.

The curriculum to become a physical therapist usually takes 3 years. That'll get you the DPT (doctorate in physical therapy). For more information: http://www.apta.org/