Six-pack progress, no crunches required
Women who did 55 minutes of yoga three times a week for eight weeks significantly improved their ab strength compared with women who did 55 minutes of other exercises, researchers at the University of Wisconsin-La Crosse found. At the end of the study, the yogis were able to do 14 more ab curl-ups than the other participants. Holding poses requires major core engagement, the study authors day.
To maximize ab sculpting, try doing uddiyana bandha, which involves gently pulling your belly toward your spine at the end of each exhale. "This activates and strengthens the transverse abdominis [your deepest ab muscle]," says Loren Bassett, a yoga instructor for Equinox in Dallas. "Hold poses for five or 10 ujjayi breaths, where each inhale and exhale lasts five counts," Bassett says. "You'll build strength isometrically because your abs have to work to keep you in proper position." (Next up, The Best Yoga Poses for Flat Abs)
If you're doing a faster-paced class, focus on your form. "When you're flowing through poses quickly, the common tendency is to arch your back," says Heidi Kristoffer, the creator of CrossFlowX, a yoga class in New York City. "Focus on keeping your spine straight—think about lengthening your tailbone and pulling in your front ribs—to keep your abs engaged."
Also, emphasize planks. They target the rectus (the wash-board muscles) and transverse abdominis, as well as the erector spinae, the set of back muscles that are part of your core, Bassett says. Side planks might be even better, because they hit all those muscles plus the obliques. "When you're in any plank, you have to engage your abs to prevent your back from arching or dipping," Bassett says. A study in the Journal of Strength and Conditioning Research found that plank variations (where feet are wide and one arm reaches forward) engaged the rectus abdominis and obliques by 27 percent more than flexion exercises (such as sit-ups) or extension ab exercises (such as single-leg extensions). (Add these yoga poses to your flow for extra ab-burning benefits.)
Here are some other ways to activate your core during every workout:
While you lift
Do a biceps curl with three-pound weights. Feel anything in your core? Didn't think so. Curl some-thing heavier, like 10-pounders, and your abs will contract to steady your body as you rep. The lesson: Heavier weights can lead to a flatter belly, says Courtney Paul, a trainer at YG Studios in New York City. Beyond lifting heavier, you can maximize ab sculpting throughout your entire strength-training workout by making a few subtle form adjustments. (Still not sure about lifting heavy? These other reasons to lift heavy will convince you.)
To begin, when doing upper-body moves like biceps curls, triceps extensions, and overhead presses, keep your ribs "closed." (When ribs are "open," they poke forward and your abs turn off, so keep your spine long and neutral and your abs fully engaged.)
"This will ensure that your rectus abdominis stays firm and contracted throughout the move," says Michele Olson, Ph.D., a professor of exercise physiology at Auburn University at Montgomery.
For lower-body moves, including squats and lunges, focus on pulling up your pelvic floor muscles with each rep (pretend you have to pee and that you need to hold it). This will engage the hard-to-target transverse abdominis. To get more ab action while doing exercises for your back, such as rows and reverse flyes, stand about 10 inches from a wall and lean forward until your forehead just touches it. Do your reps in this position. "It will force your abs to fire isometrically while you do the moves," Olson says.
And you may want to add in more single-leg exercises. Balancing can indirectly work abs by turning them on to help stabilize your body. For example, single-leg dead lifts fire up your obliques to keep you balanced as you hinge from your hips and extend one leg behind you while lowering a weight toward the floor with the opposite hand.
Whatever you do, don't slouch. Omri Rachmut, a trainer forBarry's Bootcamp in New York City, emphasizes perfect posture during every lift. "Keeping your head, shoulders, and hips aligned allows your core muscles to work more efficiently while you train," he says.
Take Laurie Cole's SoulCycle class in New York City and you'll be told to hold a one-minute plank before you pedal. This wakes up your abs and cues you to keep them tight, she says. Otherwise, they may cruise lazily through class, while your butt and legs do the work.
When you're in the saddle and riding at a moderate intensity, your ab muscles are continuously engaged at relatively low levels (about 8 percent of muscular voluntary contraction, to be exact), according to a study in the Journal of Applied Biomechanics. So for added belly burn during class, draw in your stomach from the rib cage while squeezing the muscles directly below and around the belly button, which keeps your abs engaged, says Monique Berarducci, a SoulCycle instructor in Greenwich, Connecticut. Then kick up your intensity and you've got the cycling equivalent of sit-ups: Ab engagement is significantly higher during sprints (17 to30 percent) and when riding out of the saddle (17 to 22 percent), the same study found.
"You have to keep your abs flexed to stay balanced and in control," Berarducci says. When you're out of the saddle, stretch your arms in front of you (keep a soft bend in your elbows, and let your hands rest lightly on the handlebar ends) and pull your hips back over the saddle. This creates more distance between your chest and hips, which gives your abs more room to work. Also, eliminate excess bouncing when you're riding out of the saddle, and nix side-to-side swaying when you're seated. This forces your midsection to work along with your legs, hips, and glutes, Berarducci says. (Pair spinning with yoga and you'll get great ab cross-training benefits.)
Vary your routine to include hill and sprint sessions and you'll firm your abs as well as your butt and legs. "When you run fast or up hills, your arms have to move quickly to help propel you, and this requires your abs to work harder," says Jason Karp, Ph.D., the owner of Run-Fit in San Diego and the author of The Inner Runner. (Try this speed-building hill sprints workout to see for yourself.)
For the most arm-pumping, ab-firming power, bend your arms 90 degrees (it's tougher to pump them to your advantage at a bigger angle). Keep elbows tight to your sides and swing forearms at as light angle toward your midline with hands loosely cupped. "Relax your arms and hands so there's no tension in your upper body, which helps your arms pump faster and better," Karp says.
For boot camp class
Explosive plyometrics—burpees, jumping jacks, box jumps—are both serious ab sculptors and calorie crushers. When Portuguese researchers put hand-ball players on a 12-week strength program and added plyos for the last seven weeks, the subjects reduced their belly fat by 12 percent. "Explosive moves enlist your entire core to stabilize and/or propel you, which results in maximal ab engagement," says Laurel Blackburn, the owner of BootCamp Fitness and Training in Tallahassee, Florida, who recommends squat thrusts (burpees minus push-ups), mountain climbers, and jump squats.
Throwing, tossing, or slamming a weighted ball are also good moves for tighter abs. Diane Vives, the owner of Fit4Austin/Vives Training Systems in Austin, Texas, says exercises like the overhead ball toss and the lunge with rotational ball toss work the core 360 degrees in two different ways: "They steady the pelvis and lower body to keep you supported while you toss the ball, and they help you accelerate as you throw and decelerate as you catch."
And if you do any of these exercises on an uneven surface, like a Bosu ball or sand, you'll skyrocket your ab strengthening, Rachmut says, because you have to brace your core so you don't wipe out.