That's why we went to the pros to find out exactly which moves will make a noticeable difference, fast. (Coupled with healthy eating habits, naturally, because you know abs are made in the kitchen). Get ready to work it, girl.
1. Cable Twist
Your core consists of so much more than just your upper and lower abs, says Adam Rosante, certified personal trainer and author of The 30-Second Body. “Your core actually includes everything from your pelvic floor all the way up through your spine, and its job is to stabilise the spine while your extremities are in motion,” he says. This move forces you to maintain that core stability while rotating your torso, giving you an extra burn on your obliques.
Try it: Stand with your right side facing a cable stack. Set the cable at chest-height, and take the handle in your right hand with left hand clasped on top. Extend your arms out in front of you. With abs tight, twist your torso to the left, keeping your hands at the centre of your chest the entire time. Return to the start. That’s one rep. Complete 10 reps to the left, then turn to face the opposite direction and complete 10 reps rotating to the right.
But be careful not to: Pull on the cable, which turns it into a shoulder exercise instead of an abs one. “Really be sure to keep your hands directly in front of your chest throughout the movement, and visualize your entire torso working in unison,” says Rosante. Oh, and don’t sweat it if you don’t have access to a cable machine. Rosante says you can use a resistance band instead—just anchor it at chest-height to a sturdy object, then follow the same instructions.
2. Stability Ball Knee Tucks
Unlike a crunch, which puts unnecessary—and unwanted—stress on the spine, this exercise safely works both your abs and overall core because you’re working on an unstable surface, says Fabio Comana, certified personal trainer and exercise physiologist at the National Academy of Sports Medicine.
Try it: With knees placed on the center of the stability ball and hands positioned firmly on the floor, walk your body out to a plank position so that your butt, shoulders, and head are aligned. (“Imagine a stick is resting on your spine; it should make contact with all three regions,” says Comana.) Engage your abs and hip flexors to bring your knees forward. As they move toward your chest, your spine will flex, activating your abs. Hold the tuck for a second or two, then slowly return to start. That’s one rep. Complete 10 to 15 reps.
But be careful not to: Compromise your plank position. “Remember to get that straight line all the way across,” says Comana. “If your hips are sagging toward the floor or hiked up like a pike, it’s not going to be very effective.” And don’t slack off on that knee movement. If you don’t bring the knees forward enough to flex the spine all the way into your chest you'll only be working the hip flexors, Comana says.
3. Forearm Plank
Come on, you knew this one was going to be on the list. Every trainer has you doing planks because they work, says Mark Langowski, certified personal trainer and CEO of Body by Mark and author of Eat This Not That for Abs. “You’re engaging so many muscles at once, and it helps strengthen all of the core muscles surrounding the spine to help prevent back injury,” he says.
Try it: Start in pushup position, but instead of resting your weight on your hands, bend your elbows and rest on your forearms. Your body should form a straight line from head to toe. Tighten abs and hold the position as long as you can. Keep track of your time, and aim to beat it with every workout.
But be careful not to: Hold for so long that you sacrifice your form. “Planks are something that you build from every time you do them,” says Langowski. “So if you start with holding one for 20 seconds, the next time you can go for 25. But if you jump out to a minute from the get-go, because that’s what all your friends on Instagram are doing, your hips are likely to sag too low or pike too high, and that’s asking for an injury.”
4. Side Plank
The younger sister of the standard plank, the side plank isolates the obliques even more, says Langowski. “It recruits almost as many muscles as the front plank, and helps tighten and tone to give you the sexy lines down the sides of your abs,” he says.
Try it: Lie on your left side, resting your left forearm on the floor for support. Raise your hips up so your body forms a straight line, squeeze your glutes, and tighten your abs. (Your weight should be on your left forearm and the edge of your left foot.) Hold for 30 seconds or until exhaustion, then lower to the ground and repeat on the right side.
But be careful not to: Get distracted. “The most common mistake I see is people lose focus on what muscles they’re engaging and have really sloppy form,” says Langowski. “Focus on drawing your belly button in and pressing your hip up to the sky.”
This exercise works your lower back like woah, which Rosante says is all too often overlooked. “When you work one muscle group, you need to work the opposite one that helps support it,” he says. “So if you work your abs, you also need to do your lower back. If you work your chest, you also need to do your back.” Best part: This move requires zero equipment, so get on the floor and go.
Get instant results: Lie facedown on the floor with arms outstretched overhead and feet together. Lift your chest and legs at the same time, so your chest and thighs both come off the ground. Hold for a beat, then return to start. That’s one rep. Aim to complete 12 to 15 at a time.
But be careful not to: Overarch your lower back. Rosante says it happens a lot, and can lead to injury. “Think of lengthening through the fingertips and toes—so reaching as far out as you can in both directions—and keeping your belly button pulled in,” he says.
6. Medicine Ball Slams
Not only does this move target the abs, butt, and hips, but it’s also an insanely effective way to get out some aggression. We recommend working it into your routine after a particularly stressful day at the office.
Try it: Stand with feet slightly wider than shoulder-width apart, holding a moderately heavy med ball with both hands at chest level. Lower into a squat until thighs are parallel with the floor, then drive through your heels and straighten legs, bringing the med ball overhead. With abs tight, immediately slam down the ball down toward the floor, engaging your hips and abs to give you as much force as possible in your slam. That’s one rep. Quickly retrieve the ball and repeat for 30 to 45 seconds.
But be careful not to: Arch your back as you lift the ball overhead. “You want to tilt the hips backward and keep your trunk stiff as you bring the ball behind the midline of your body to avoid injury,” says Comana. Furthermore, be sure not to slam the ball directly under your body—that’s just asking for the ball to bounce back and hit you in the face. Not fun.
7. Shoulder and Knee Taps
While planks are an amazing exercise, Langowski says they’re static holds, and you want dynamic movement in your routine as well. “It helps keep the muscles engaged because you’re moving around,” he says. This exercise works the abs, obliques, lower back, and arms all at once. Now how’s that for efficiency?
Try it: Start in a pushup position with hands on floor, abs tight, glutes engaged. Lift your right hand and tap your left shoulder, then return it to the floor. Immediately lift your left hand and tap your right shoulder, then return to floor. Now quickly bend your right knee and bring it to your left elbow, then return to start. Immediately bend your left knee and bring to left elbow, then return to start. That’s one rep. Continue to do this sequence without rest for one minute.
But be careful not to: Lift your hips high or sink below your midline. Langowski says you want to keep your abs tight the whole time, so your body stays in a straight line. And don’t worry if your elbows can’t touch the knee. Langowski says it’s not necessary, so long as you bring it as close as you can. The gap will close the more you practice.
This article originally appeared in Women's Health US.