I teach Adapted P.E. but I could teach general P.E since I have a P.E credential. To teach P.E you need a degree in Kinesiology or Physical Education, depending on the school you attend. To get hired in a public school you need a single subject teaching credential in P.E.
I went to Cal State Northridge, got my degree in Kinesiology with an Adapted P.E option. I got my P.E and Adapted P.E sprecialist credential. Its tough, along with all the course work you need to pass around 15 skills test in every sport out there to name a few: gymnastics, swimming, golf, track and field, badmitten, tennis, basketball, baseball, fooball and dance. There are a few more also. I had to student teach at a middle school one semester and the other semester I student taugh while I was being paid on the job. I work for LAUSD. Its really a great job.