The strength and conditioning coaches are in charge of the weight room. They are in charge of all offseason and in-season weight lifting and conditioning programs. They put the players through all of their weight work, conditioning drills, running, etc. It's a vitally important position.
Offensive and defensive quality control coaches work on a lot of film breakdown and usually run the scout team. For example, an offensive quality control coach will do much of the film breakdown on the defenses of all of the upcoming opponents. Entering all plays, results, formations, personnel groupings in the computer that synchs up with the video editing system. He will also self scout the offense to be sure that they aren't being too predictable, among other things. The offensive and defensive quality control guys will also produce all of the play cards for the scout teams (reserves and practice squad guys) who practice against the starters. They teach these reserves how, for example, how the Patriots line up, their personnel groupings, and what plays they run and then the reserves run these plays against the starters.
