Flatten & Firm in 15 Minutes!

The core seems to be a tough spot to whittle down. Whether you are carrying a spare tire or you just don't have that hourglass figure you envisioned, we have the moves to tone you up! A good core includes a strong back, so we picked moves that work both the front and the backside of the abdominal wall. Now, we do use a variety of equipment for these moves, but it's well worth it. You can also sub out medicine balls with weights as you see fit! Do each of the seven moves for one minute each, rest for a minute, then repeat!

What you need:

• Stability ball
• Medicine ball
• Gliding disks

Oblique Leg Lift Crunch:

When doing this move, it's important to make sure you're lifting yourself using your core and not your arm that's resting on the ground.

• Step 1: Lie down on your right side with your legs fully extended. Your left foot should be stacked on top of your right foot.
• Step 2: Use your right arm as a kickstand as you lift both your upper body and your legs off the ground. Try to get your upper and lower body as close together as you can, really digging that hip into the ground. Don't push off your right hand, use your core to bring your upper half to your lower half.

Do as many Oblique Leg Lift Crunches as you can for 30 seconds on your right side, then switch sides for another 30 seconds on your left side.

Stability Ball V-Pass:

You should definitely be feeling the burn when you perform this move. It works your entire core!

• Step 1: Lie face up on the floor with arms and feet extended, grasping a stability ball with both hands.
• Step 2: In one fluid movement, use your entire core to lift your arms and legs off the ground, keeping legs and arms straight the entire time.
• Step 3: Transfer the ball from your hands to your feet and allow yourself to lower back down to the floor. Note: make certain to keep your lower back pressed into the ground to sprotect your back throughout the movement.
• Modification (Beginner): Bend knees while performing move or ditch stability ball altogether.

Do as many Stability Ball V-Passes as you can for 60 seconds — these are challenging, rest as needed!

Ab Cyclones:

This move is a great way to target your abdominals. If the ground is too hard on your back, you can put your hands underneath you, between your butt and lower back.

• Step 1: Lie flat on your back with your hands down at your sides, palms down. For extra comfort, you can place them underneath you, between your butt and lower back.
• Step 2: Keeping your legs straight, raise them up until they form a 90-degree angle with your upper body.
• Step 3: Drop them down and to your left, keeping your legs straight the entire time.
• Step 4: Now rotate them to the center, straight in front of you about 6 inches off the floor.
• Step 5: Swoop them to your right side, keeping the same hovering distance from the floor. Pull them back to that 90-degree angle. That's one rep. Note: If your lower back starts to arch and is no longer touching the ground, bend your knees and do not drop your legs as low.

Perform Ab Cyclones for 30 seconds going clockwise and 30 seconds going counter-clockwise.

Boat Crunch:

This move will test your balance and keep your abs engaged! For an added challenge, pulse your arms up and down!

• Step 1: Sit down, bend your knees, then raise your legs until the knees are over the hips. Raise your upper body until you create a "V" from the chest to the thighs. Extend the arms forward for balance. Pull the belly button in so you are not arching your back. Try to get your calves parallel with the floor.
• Step 2: Inhale and extend the legs out as you drop the upper body, opening the "V" to become almost parallel with the floor. Think about being long. Flex or point the feet.
• Modification (Beginner): Rest on your elbows. Inhale and extend the legs out as you drop the upper body, opening the "V" to become almost parallel with the floor. Think about being long. Flex or point the feet. Exhale and crunch the legs back to the starting position. If the boat pose is too easy for you, you can come into a full V-sit. Find the balance on your sit bones and completely straighten the legs. This will recruit more strength from the lower abdominals.

Perform :60 of Boat Crunches.

Crazy Ivan:

Even if you don't have a medicine ball, this is a great move. One modification of this workout is to ditch the weight so it's still an effective move even without equipment!

• Step 1: Sit down on a mat with your medicine ball next to your left hip, keeping your knees bent. Slowly lean your upper body back to a 45-degree angle.
• Step 2: Raise your feet up with knees bent, and cross your right foot over your left.
• Step 3: Rotate your upper body to bring the medicine ball from your left hip up and across so that it is over your right shoulder. It should be above your forehead.
• Step 4: Do as many reps as you can within 60 seconds. Alternate your starting side after 30 seconds.
• Modification (Beginner): Ditch the medicine ball.

Perform :60 of Crazy Ivans.

Plank Skis with Sliding Disks:

Start in a forearm plank position, placing gliding disks under your toes (sun paper plates for carpet and/or small towels for hardwoods). If your elbows are sore or sensitive, pop up to a push-up plank position.

• Step 1: Find a smooth surface and get into forearm plank position, placing a towel or disks under your toes. If your elbows are sore or sensitive, pop up to a push up plank position. Your back should be straight and aligned with your head and toes.
• Step 2: Slide your feet up to your right elbow. Your knees should naturally bend. Try getting your left knee to the right elbow. Feel the twist throughout your torso.
• Step 3: Slide your feet back to start position and then reverse the movement. Tuck your right knee into your left elbow this time. That's one rep.

Do as many Plank Skis with Sliding Disks as you can for 30 seconds on your right side, then switch sides for another 30 seconds on your left side.

Feet on Medicine Ball Pushup:

Push-ups are great to work your arms and back, but with the added medicine ball, your core will be engaged while you keep your balance!

• Step 1: Get in push-up position with your feet together and toes rested on a medicine ball.
• Step 2: Keeping your core tight and body in as straight of a line as possible, lower into a pushup by bending at the elbow with your toes staying balanced on the ball.

Perform :60 of Feet on Medicine Ball Push-ups.

Remember, do each exercise for one minute straight, and then immediately move onto the next one. After you've completed each exercise, rest for one minute and then complete the entire sequence again. Happy abbing!

Want more calorie-blasting workouts in 20 minutes or less? Check out the Your 14 Moves Away From the Perfect Bubble Butt, Cardio Hip Hop Dance Party, VIDEO: 20-Minute Beginner Tabata Workout, and Buzzworthy 8-Minute Abs Routine!