There are six steps to recovery from a concussion:

  1. Rest, quiet
  2. Light aerobic activity
  3. Sports-specific activity
  4. Non-contact training drills
  5. Full contact practice
  6. Full contact games

Allowing 24 symptom-free hours before progressing to the next recovery step means that a player should be sidelined for at least a week.  And please note that if symptoms return at any step in the process, the player should be stepped back, and the 24-hour symptom-free process should start again at the previous step.