Confirmed (by SkySports at least) that "all football activity" means training as well.
Methinks a four month long sulk back at home in Montevideo is imminent.
From FIFA:
The player Luis Suárez is banned from taking part in any kind of football-related activity (administrative, sports or any other) for a period of four (4) months in accordance with art. 22 of the FDC.
Administrative is the interesting one. I'm wondering if that means he could not...