I am late to this discussion and much has been had already but I think that is an unfair assertion on PhysEd teachers. While I have never taught, I did take the required course load "back in the day". The Phys Ed (now Kinesiology) had some of the best training and highest course loads around. Here is something that might blow your mind, as a phys ed student, we had human cadavers in our Anatomy lab, the Bachelor of Nursing students that shared our building did not. All there anatomy training was on models.
Many of my classmates at the time are now teaching phys ed but many other subjects or administration. @Mark H. and I have a mutual friend that is an award winning STEM middle school teacher that started her training as a phys ed teacher when I did mine.
The assertion that Phys Ed teachers are just dumb jocks is almost on the level as saying the Riders are a well run football team.