Check out Women's Health's Fitness Faceoff every week to learn which moves will best help you reach your fit goals. Here's this week's faceoff:
The real secret to a sexy stomach is carving out those lines to frame your budding six pack (a.k.a. your obliques).
Don’t be fooled by appearances here: The plank knee taps might look more advanced, but it’s actually the plank sweeps that’ll carve killer obliques best. “Your abs are maximally contracted the entire exercise so they don’t get a break, and you have to resist the weight of your leg being shifted underneath you,” explains Marc Perry, CSCS, founder of BuiltLean. “Plus, you have to do a full twist to have the knee hit the opposite elbow, which works the obliques fully.”Both moves target the entire core musculature—internal and external obliques, rectus abdominis, and transverse abdominis—but in the other move, moving from plank to downdog actually relieves the tension from your abs and shifts it more toward the shoulders and arms. In addition, while reaching for the opposite leg creates some rotation, it doesn't challenge the obliques quite as much, Perry adds.