"Hearst Magazines and Yahoo may earn commission or revenue on some items through the links below." If you've completed a core workout—or 100 of them—over the years, you likely know what crunches are ...

Just because you’re new to working out and your body fat percentage might be higher than you’d like doesn’t mean your beginner ab workout needs to be relegated to a middle school regimen of situps.

• Sit-ups target your abdominal muscles, back muscles, and hip flexors, while crunches only target your abdominal muscles. • Neither sit-ups nor crunches alone burn abdominal fat. Overall activity and ...