Do you need medical training to be a porter?

I think I might have a fascination for people with a cast. My girlfriend was in an accident, and I helped her through her long recovery. At first, I thought my desire to help was due to the fact that she is my girlfriend. I have taken her to the hospital for appointments and saw many people with casts on. Each time, I wanted to offer istance if I could. If they seem to be able to manage on their own, I would just sit, and watch them from afar. I noticed that there are guys at the hospital,who push patients in wheelchairs fro one place to another. Do you need some sort of medical training for this type of work? What other duties do these people have?