the leg raise i have done.
some other exercises ive done and really liked are:
standing guard situps: you and a partner are both standing. you pull guard and you partner keeps a good base and keeps standing. then do situps from here. its a killer on the abs (you wont be able to do more than 20) and it works out whichever muscles help keep your guard closed.
climb-arounds (for lack of a better name): same setup as before. you pull guard and your partner stays standing. have your partner extend his arms out to his sides like a scarecrow and shimmy around to his back and the whole way around back to guard. 3 times around will be sufficient for most. this helps build the same muscles that keep you on your partners back when he's rolling around trying to escape.
elevator sweep > taking the back: lie on your back, have your partner stand, and put your feet on his hips and control his sleeves/wrists. pull his weight over you and hold him in the air like you would with an elevator sweep to a helicopter armbar or something. now, using an armdrag but slowly, lower him down onto you, turning him in midair using your feet and hands so that when he actually comes to rest on top of you, you have his back. you can also do leg presses first from the elevator sweep position. helps build sensitivity in your feet as well as well as the balance to keepyour opponent stable.
