They are called mat drills because originally they were conducted on old wrestling mats in the weeks leading up to spring football. Lou Holtz and Bobby Bowden are considered the founding fathers of workouts like these that get players ready for action and help in team-building.
You may miss football. I'm not sure you miss this, but it's a building block to success in the fall. Check out these videos from the Dartmouth football program. (Editor's note: depending on your age, you might want to mute the computer for the second video – I did. ;-)