True, but you can't legally do much with them. You are in a public place and have to be extremely cautious.
There is the option of doing manipulation under anesthesia. When the athletes have an injury to work out, they are given a muscle relaxant that leaves them pretty incoherent. Some specialists even do manipulation while the athlete is completely under. This often applies to very muscular athletes who can be extremely difficult to work on.
I had a friend who 6' 3'' tall, strong as an ox and about as smart. He dislocated his his shoulder while being careless and I took him to the emergency room at the hospital. He had consumed a lot of beer (his favorite food group) that day. I got him undressed, in a gown and up on a table. The doctor worked quite a while, but couldn't pop the shoulder back in because his muscles were so strong and he was resisting. So they shot him up with muscle relaxants and narcotics until he was so out of it he couldn't feel much of anything.
The doctor then got right up on top of his bare (bear) chest and while three other staff members and I held my friend down, he worked the affected arm this way and that. He would get off, move the patient on his side and remount him all while my friend moaned some and laid there helpless. The doc final got the shoulder to pop in after pretty much molesting the guy. While in the recovery room, my friend was so out of it that I could have done almost anything to him.
The most interesting thing is that, when my friend came to, he couldn't remember what the doctor did to him. If I were not with my friend, the doctor could have done anything he wanted because its his job. That is often how athletes have to be treated for sports injuries. Imagine having some muscular hunk of a footballer undressed, drugged and lying on a table waiting for you to work on his body. I bet sports medicine doctors are a happy lot.
