After watching a four-goal collapse in the 3rd period, I went digging through my computer for a few .pdfs that I've had for a while. Sure enough, I found an old strength/conditioning manual from an NFL team and then found a link online.
This is from the Houston Texans. What makes it important is that NFL teams have both optional and mandatory offseason conditioning programs, plus minicamps. The amount of time that players are completely on their own without something on the horizon is minimal. And yet this is a 68-page guide that specifically handles just that down time.
http://fastandfuriousfootball.com/wp...ingProgram.pdf