Any muscle can be safley worked daily, whether you should or not is a different matter. Your routine is way to high volume. The reps are so high that the intensity must be seriously lacking. You either need to go slower (as you are probably using too much momentum), or add weight/resistance. Also, forget about lower abs middleabs etc and start looking at the core as a whole.
Quote from todays' tip of the day on t-nation Today's training tip comes from Chad Waterbury: Direct Ab Work? If you incorporate the correct exercises in your workout plan, there's very little need for direct ab work. Compared to many abdominal isolation exercises, I've seen more dramatic ab improvements with Zercher squats, side deadlifts, regular deadlifts, and overhead presses. These will blow away almost all "isolation" ab-training programs. I'm not saying I oppose ab training. There are some excellent exercises to help complete the total package. I frequently use Janda sit-ups, decline sit-ups, and hanging pikes. But nix those crunches; there are much better alternatives!
Definitely go for some exercises other than abs. Turkish get-ups with kettlebells have given my abs a good workout, and generally anything really hard you do will work the abs, so long as it isn't an isolation exercise. Janda sit-ups and full-contact twists are my favorite ab exercises so far, and John Peterson's last Tiger Move (cheesy I know, but that's what they're called) can help tone up, but I'm not sure of it's benefits for strength. I haven't tried them, but I've also heard that hanging leg raises are killer.
wow, i see a lot of "do 100 situps" in this thread. Abs are like any other muscle, and intensity is important. Can't really go wrong with weighted situps, for reps of 5. That's just my take on it. Also, pull ups, deadlifts, and overhead presses have an amazing effect on you core stabilizers. However, if your goal is definition, burning fat is really important. I've been trying out the Tabata method with weighted situps. pretty sweet, but only once in a while.
I knicked mine off a mate, but make sure you dont pay any more than a tenner for one. I think they sell them in next? If your training for strength you might want to pu your full contact twists into a 3x5 or 5x5 program, then add weight. That'l build strength more
