The NCAA formally adopted legislation today outlawing old school "two-a-days"; which to be honest I'm not sure really were occurring much if at all these days. What now is allowed is a padded practice and a walk-through (without pads).
From the NCAA's release:
Division I football players will no longer have multiple contact practices a day in the preseason, the Division I Council decided at its April 13-14 meeting in Indianapolis.
The action comes just a few months after the Division I Committee for Legislative Relief issued a blanket waiver to allow the football preseason to start up to a week earlier. That decision allowed schools to decide how best to manage their practice schedule while retaining 29 preseason practices.
A single day may include a single, three-hour, on-field practice session and a walk-through. During walk-throughs, protective equipment such as helmets and pads can’t be worn, and contact is prohibited. Walk-throughs also can’t include conditioning activities and, in the Football Championship Subdivision, are limited to two hours in length. Three continuous hours of recovery are required between on-field practice and a walk-through. Activities such as meetings, film review, medical treatment and meals are allowed during recovery time.
The Division I Football Oversight Committee supported the recommendations, as did the NCAA Committee on Competitive Safeguards and Medical Aspects of Sports. Research says that practices with tackling are more likely to cause a concussion than practices that don’t include tackling. Additionally, the decision allows for appropriate recovery time to prevent both heat illness and overuse injuries.