One of the messages I convey to all of my classes the first weeks of school, and throughout the school year, is that there is a difference between physical education, recess and after school athletics. My approach is a skills-based approach where small-sided, high engagement games are often at the core of daily lessons.
Sportsmanship is another conversation we have throughout the school year. While we do play games and compete, I often times have to remind students of what being a good sport means. Sometimes they equate winning with having fun. One of my t-shirts says "Calm down. It's P.E. not the Olympics!" I want everyone to have fun while learning on the move. As well, I tell them throughout the school year they are NEVER graded on winning or losing but on doing their best!