Towel Abs

You don't need disc sliders for this exercise; just grab a pair of towels and get to work.

• Begin in plank position with two towels under the balls of your feet (or paper plates if you're on carpet).
• Slowly bend both knees in toward the chest while keeping the arms straight, shoulders over the wrists, and maintaining a flat, tabletop back. If this is too difficult, draw one knee in at a time.
• This counts as one rep.
• For a variation, draw both knees to the right foot, straighten the legs back behind you, then draw both knees to the left foot.
• This counts as one rep.

Elbow Plank

This tried-and-true ab exercise will target all your abdominal muscles.

• Start on the floor resting on your forearms and knees.
• Step your feet out one at a time, coming into a plank position.
• Contract your abs to prevent your booty from sticking up or sinking. Your spine should be parallel to the floor, with your abs pulling toward the ceiling.
• Hold 30 seconds and work your way up to one minute, as you get stronger.

Knee Driver

You'll feel the burn — in your abs and shoulders — from this bodyweight exercise, which also adds a boost of cardio.

• Begin in an elbow plank position with the abs engaged.
• Draw the left knee into the chest. Then step the foot back to the elbow plank position. Now draw the right knee into the chest and then step it back to the elbow plank position.
• This counts as one rep. Start with 12 to 15 reps, and do at least two sets.

Plank With Knee Taps

This seemingly simple exercise will get your deeps abs burning.

• Start resting on all fours.
• With your palms flat, raise up off your knees onto your toes. Keep your hands directly below your shoulders.
• Contract your abs to keep yourself up and prevent your bottom from sticking up. Remember to keep your belly button pulled in.
• With your head and spine in line, keep your back flat — don't let it curve. Picture your body as a long, straight board.
• With control, slowly tap your left knee to the ground without moving your hips. Lift your left knee back up, returning to the starting position. Repeat the same movement with the right leg. This completes one rep.
• Complete two sets of 10 reps.

Twisting Mountain Climber

Get ready to obliterate your obliques with the ultimate core move. Mountain climbers are especially great because they provide intense cardio also. Start in plank position and prepare to burn some major calories.

• Engage your core.
• Explosively bring your right knee up toward your left elbow while twisting your obliques.
• As soon as you return your right foot to the floor, explode with your left leg, pushing your left knee toward your right shoulder. The movement and transitions should be fluid, without pauses, in this exercise.
• Aim to complete 10 reps on each side for a total of 20 reps. Rest and then do one or two more sets.

Side Plank

An effective way to carve and strengthen your deep front and side muscles is side planks. Fire up your obliques and arms at the same time.

• Start in plank position (the top of a push-up) and roll to your left side, allowing your feet to roll too, so you're balancing on the outside of your left foot and the inside of your right. To advance this move, stack your right foot on top of your left.
• Reach your right arm toward the ceiling and lift your waist away from the floor to make your obliques fire away. Press your left inner thigh up into your right inner thigh; this helps stabilize you even more.
• To take pressure off of your wrist, press your left fingertips into the floor.
• Hold for 30 seconds, working toward a full minute. To complete a set, repeat on the other side. Do three sets.

Reverse Crunch

This move targets your lower portion of your abs specifically. Aim for 15 reps and at least two sets.

• Lying on your back, lift your legs in the air with your knees bent. Place your hands on the floor beside you.
• Without momentum, use your lower abs to slowly curl the hips off the floor and into your chest. Slowly lower them back to the starting position.
• This counts as one rep.

Scissor Kick

Like reverse crunches, these target your lower belly and will strengthen your core.

• Lie flat on your back. Extend your arms so they're against the sides of your body with your palms pressing into the floor, or bend your elbows and place your palms under the back of your head. Bend your knees and draw them into your ribs. This will make it easier to pull your navel in toward your spine and actively press your lower back flat on the ground.
• Lift both legs straight up toward the ceiling, continuing to engage your abs and pressing your lower back into the ground. Keeping your core strong, slowly lower your right leg down toward the ground until it is a few inches above. Then slowly scissor your legs, lifting your right leg back up as you lower your left leg down toward the ground.
• This counts as one rep. Ten reps make a set; do at least two sets.

Double Leg Lift

On top of working your abs and obliques, this move also doubles as a great thigh toner. Plus it's a great modification if for hanging leg raises [7], too.

• Lie flat on the ground with your legs extended straight up toward the ceiling. Place your hands underneath the back of your head. For added stability, place your arms out to your side, allowing the palms to grip the floor (much like you would in a push-up position).
• Pressing your lower back into the ground, slowly lower both legs down toward the floor, then slowly raise them back up. If this is too difficult, lower them as much as you can or lower one leg at a time.
• Complete 10 to 15 reps.

Bicycle Crunch

This tried-and-true core move targets your entire abdominal wall, so the lower part of your abs is definitely getting worked.

• Lie flat on the floor with your lower back pressed to the ground (pull your abs down to also target your deep abs). Interlace your fingers, and put your hands behind your head.
• Bring your knees in toward your chest, and lift your shoulder blades off the ground.
• Straighten your right leg out to about a 45-degree angle to the ground while turning your upper body to the left, bringing your right elbow toward the left knee. Make sure your rib cage is moving and not just your elbows.
• Now switch sides, and do the same motion on the other side to complete one rep (and to create the "pedaling" motion).
• Do 15 to 20 reps per set. Do two to three sets.

Ball Pike to Plank

This killer move focuses on your lower abs as the bottom half of your body is in full control of the ball. First things first: make sure the ball is sized to your body; you should be able to sit on the ball with 90-degree angles at your hips and knees. If you don't have an exercise ball, use two sliders or paper plates on carpet to slide up to pike position.

• Start in a plank position with your hands directly under your shoulders and your shins on the ball.
• Do not allow your lower back to arch. Keep your feet, pelvis, and shoulders in one long line.
• On an exhale, pull your abs deeply to your spine and use your abs to fold your body in half, pulling the ball forward toward your hands as your pelvis moves up in the air.
• Your toes will move onto the top of the ball, and your back will become perpendicular to the floor, like a handstand. Allow your head to fall between your arms, keeping your neck long and in line with your spine.
• Lower yourself back into a plank position, and do not allow your pelvis to sag below your shoulders.
• Do 10 reps for two to three sets.

High Knees

You may think this move only targets your lower body, but it will fire up your core, too. Plus, it will give you a burst of cardio to get your heart rate up.

• Hold your hands at waist level.
• Hop the right knee up toward your hands, then quickly switch legs and hop the left knee up.
• This counts as one rep. Do this move for 30 to 60 seconds.

Russian Twists

Add weights to Russian twists to blast your front ab muscles, transverse ab muscles, lower back, and obliques.

• Sit on the ground with your knees bent and your heels about a foot from your butt.
• Slowly recline backward until you feel your lower abs engage. It is really important, and difficult, to keep your back straight, but don't let it curve.
• Place your arms out in front of you with your hands one on top of the other. Your hands should be level with the bottom of your ribcage.
• Pull your navel to your spine and twist slowly to the right. The movement is not large and comes from the ribs rotating, not from your arms swinging. Inhale through centre and rotate to the left. This completes one rep.
• Do 16 full rotations to complete a set.

Low to High Woodchop

This exercise works your core, shoulders, back, traps, and arms, all while helping you build muscular endurance. Bonus: your heart rate will stay elevated, which means you're torching calories.

• Squat, and twist left to hold the dumbbell on the outside of your left leg.
• Exhale, and lift the weight diagonally across your body, ending twisted to the right with the dumbbell above your head. Pivot on your left foot as needed.
• The move is a bit percussive, so focus on the rotation initiating in your torso.
• Control the weight back up to the starting position to complete one rep.
• Remember you are moving with force but also control. Don't give into the momentum of swinging the weight around. Do three sets of 15 reps on each side.

V-Sit

Although this move is a little more advanced, it will make your lower abs burn. Try to lift your upper body up off the floor as much as possible so your arms meet your knees.

• Lie on your back, and reach your arms rigidly to your side, off the floor. Lift your legs off the floor and point them, so they are at about a 45-degree angle. Lift your head, so your shoulders are off the floor as well.
• When you're ready to begin, lift your upper torso off the floor, and bend your knees. You can lean back to make this move harder or come up more to make it easier. Slowly lower your upper body back down to the floor, straightening out your legs as you do so. Stop when your back is on the floor, but not your head, shoulders, or legs.
• This completes one rep. Do 10 to 12 reps per set, and do two to three sets.

V Crunch

Fire up your lower abs with this go-to bodyweight core exercise. Try to lift your upper back off the floor so your hands touch your feet.

• Lie on your back, and lift your legs and arms up, so they are extended toward the ceiling. Lift your upper back off the floor, reaching your hands toward your feet.
• Lower your legs toward the floor while reaching your arms overhead, keeping your shoulders off the mat and lower back pressed into the mat.
• Repeat the crunch motion to complete one rep and aim to 10 to 15 reps.

Hanging Leg Raise

Master this advanced move, and you'll have those lower abs showing in no time. To modify, you can do this move with bent knees.

• Start by hanging on a pull-up bar with palms facing out, or use the ab straps and hang with your arms inside of them. Do use a box or bench if you need help reaching the bar.
• Pull your shoulder blades down your back to keep your shoulders away from your ears.
• Engage your abs as you fully extend both legs, lifting them up simultaneously with control.
• Lower the legs down slowly and return to the starting position. This completes one rep.
• Avoid swinging during this move to ensure that you're really working your abs.
• Do two sets of 10 reps.

Battle Ropes

Using battle ropes is a fantastic full-body exercise: in addition to forcing you to engage your core, your entire body will need to kick into gear to stabilize you. On top of that, your heart rate will shoot up which helps burn calories. Here are two variations to start with.

• Hold the ends of the ropes at arm's length so they are extended out in front of your hips.
• Keep your hands close together, about one foot apart.
• Bend into a semi squat position.
• Engage your core.
• Explosively raise both hands straight up into the air until they are about eye level.
• Bring your hands back down to hip height.
• Rapidly repeat this motion for one to two minutes.
• Rest and begin the next set.

Try to do three sets, with rest in between. Each week, challenge yourself by extending the time of each set.

• Hold the ends of the ropes at arm's length so they are extended out in front of your hips.
• Keep your hands approximately shoulder width apart.
• Bend into a semi squat position and engage your core.
• Begin by raising your right arm explosively. As it is descending, begin raising your left arm explosively. This should be a fluid motion that sends waves down each rope.
• Keep alternating your arms for one to two minutes for one set. Challenge yourself by adding time each week to each set or simply by speeding up.