Here's the great thing about ab exercises: You can add highly-targeted moves—like the ones on the following slides—that sculpt your obliques, make your abdominals pop, and build a strong foundation of core strength to every single workout.
To do that, you can mix abs-focused exercises with explosive moves in a HIIT routine to build muscle and torch fat simultaneously. Or, you can hit your abs at the end of a strength-training routine. Doing both is actually optimal. Switching things up keeps your body guessing and muscles growing.
What you shouldn't do is train your six-pack muscles alone—and neglect the rest of your body. "The biggest mistake people make when they're trying to get toned and muscular abs is focusing on just ab exercises and crunches day after day," says Akin Akman, CSCS, group fitness instructor and personal trainer.
In other words, you can't spot train. Perhaps more importantly, you can't work off a crappy diet. In fact, abs exercises are practically useless if you aren't watching what you eat.
"Getting toned abs is the same as getting toned anywhere else in your body—focus on clean eating and crosstraining with both cardio and strength moves to create the higher metabolic rate that will lean your body as a whole," Akman adds.
Prescription: The reps Akman recommends for each exercise that follows are meant for an ab-specific workout that will take you approximately 30 minutes to complete if you do 2-3 sets. Take as little rest as possible between reps, and give yourself a few minutes between sets. "Don't rest too long, though, because you want to keep your heart rate up and your muscles engaged," Akman says. You can also just pick and choose a few of these moves to add to the end of your strength training workout or incorporate into a HIIT routine.
If you're just using your bodyweight, keep the reps and sets high. If you're incorporating heavy weight with some of the moves, do lower reps with more sets. Modify the workout according to the intensity and duration you're looking for.