The Ivy League has decided to limit the number of full-contact football practices that teams can have in an effort to reduce the chance of head injuries to players, according to a New York Times report. A study published last year indicates that players receive more hits to the head in practices than in games. (Practices, of course, consume far more of players' active time on the field than games do.) The new Ivy policy goes well beyond the NCAA's guidelines on the subject, and is quite possibly the most stringent of any conference.
For additional background, read the 2010 article "Hits, Heads, Helmets" from the Harvard Magazine archives; it explores some of the issues in football-related concussions and describes a new helmet designed to mitigate them.
