Rigorous

I was reading my text book for my coaching basketball class. The chapter I was Reading was on practices. One of the topics in the chapter was called "Making an impact." in this section it said "Don't make the first few practices to rigorous, because this will burn out most of your players and could scar some away." I knew this was a good coaching strategy because my coach in high school had a lot of running in the first few practices. So one of by best friends quit the team so i asked "why did you quit?" He said "its to hard I'm worn out i cant do this all year."