Don’t waste time on these popular-but-ineffective ab exercises. They won’t burn fat—or make your stomach flat. Skip ’em, sister!

Crazy Amounts of Crunches
Every few years, some celeb lets it slip that she does hundreds of crunches a day. Research proves extra sit-ups won’t blast belly fat. Cardio is the only way to unearth a six-pack. Limit reps to 8-20, OK?

Twist ’n’ Shout
Twisting your core will not whittle your middle. Stop those moves that have ya spinning like a helicopter. They won’t land you anywhere.

Rush Hour
Racing to the finish line for a 100m dash is a fab idea. Racing to finish your ab routine? Not so much. Concentrate on your form for every rep.

Weighted Side Bends
Grabbing a 15-pound dumbbell in each hand and slowly going side to side isn’t gonna make your waist smaller. The weight actually makes this move easier (blame momentum). Try side crunches instead.