There are way more important reasons to strengthen your core [1] than bikini-clad weekends, and you don't need a ton of crazy equipment and a gym membership to sculpt a strong and sexy midsection! The following 12 easy-to-follow exercises use your own body's weight to tone up your tight midsection. Incorporate these into your strength-training routine for results you can see and feel.

Full Sit-Ups

• Lie on your back with bent knees and feet flat on the ground, and place your hands on opposite shoulders.
• Keeping your heels on the ground and your toes flat to the ground, engage your abdominal muscles, and gently lift your head first, followed by your shoulder blades, coming into a full-sit up position.
• Hold the position for a second, and with control, come slowly back down to lying on your back.
• This completes one full sit-up.

Oblique V-Crunch

• Lie on your right side, with your left hand behind your head and right hand on the floor.
• Press down into your right hand as you raise your straight legs off the floor bringing your torso toward your legs.
• Lower yourself back to the floor with control. This completes one rep.

Reverse Crunch

• Lie on your back on the floor. Place your hands on the floor beside you.
• Bring the knees in toward the chest with your feet together.
• Use your abs to slowly curl the hips off the floor and into your chest, and then slowly lower them back to the starting position to complete one.
• Repeat for one minute. Don't swing your legs to create momentum; use your abs to control your movement.

Bicycle Crunches

• 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).
• This completes one full rep.

Seated Russian Twist

• Sit on the ground with your knees bent, pull your abs to your spine, and lean back a few inches while lifting your feet off the floor. Be sure to keep your back straight.
• Reach your arms out in front of you, and twist your torso to the right, then to the left, repeating for one minute. Lower your heels to the ground if you need to.
• This completes one full rep.

Plank

• Balance on the hands and toes with the body in one straight line, hands underneath the shoulders and feet hips-width distance apart.
• Pull your abs to your spine, and hold this position for 30 to 60 seconds to complete one rep.

Push-Up Rotation

• Begin in a plank position with your feet in line with your hips.
• Lower your body toward the floor, and then push through your arms, returning to plank.
• Twist to the left, reaching your left arm to the ceiling without letting your pelvis rise or lower.
• Return to plank position, bringing your hand back to the floor, and perform another push-up. When returning to plank, twist to the right, and reach your right arm to the ceiling.
• Return back to plank position, returning your arm to the floor. This completes one rep.
• Perform 15 reps.

Mountain Climber

• Start in a traditional push-up starting position — shoulders over hands and weight on just your toes.
• Bring your right foot forward, bending the knee and putting weight on the ball of your foot.
• Switch legs, bringing the left knee forward while moving the right leg back. This completes one rep.

Bird Dog

• Begin on all fours with your hands directly under your shoulders and your knees directly under your hips. Bring your abs to your spine as you bring your left knee and right elbow together under your torso.
• Keeping your torso stable, straighten your right arm and left leg. Reach through your left heel to engage the muscles on the back of your leg and your butt.
• This completes one rep.

Side Plank

• Sit on your left side with your legs slightly bent and your feet stacked.
• Place your left hand about 12 inches from your pelvis.
• Push your hand into the ground, and straighten your legs as you lift your pelvis off the ground. If you have trouble balancing, stagger your feet, so the top leg is in front.
• Hold for 30 seconds, and switch sides to complete one rep.

Scissor Abs

• Lie flat on your back with your arms at your sides, palms pressing into the floor. You can place your hands under your pelvis if you feel the need to protect your lower back.
• Bring both legs straight up toward the ceiling, engaging your abs and pressing your lower back into the ground.
• Keeping abs pulled in and lower back on the ground, slowly lower your left leg until it's a few inches above the floor, then scissor your legs, lifting your right leg up. This completes one rep.

Swimming

• Begin on your stomach with your arms extended in front of you.
• Keeping your neck neutral and in line with your spine, lift your feet, arms, and chest from the floor.
• Begin to "swim" by lifting your opposite arm and leg a little higher, and then alternate sides, making a fluttering motion.
• Continue this movement for 30 seconds to complete one cycle.