10 Essential Core Exercises to Help You Tackle Everyday Activities

What do you think of when you hear the word "core"? Maybe an apple core, the center of the Earth, an essential part of a group? In our bodies, the core is the center of our skeletal system, the muscles that keep us upright, the trunk from which our branches extend. Our core is as essential to everyday living as the air we breathe and the food we eat.

Your core is made up of your midsection and all the muscles surrounding that area, including the front, back and sides. You engage your core to do almost everything—from getting out of bed or putting your toddler in his or her car seat to sneezing or walking down the street.

If your core is weak, all of these activities can suffer. To keep from injuring your back from something as simple as bending over to tie your shoes, it's important to keep your core muscles in good, working order. "A strong core is important to me because it allows me to be an active mom," NASM-certified personal trainer and coach Jen Karulf says. "Having five boys, I am constantly chasing, lifting and carrying little ones. A strong core is a necessity."

While there are many core-building exercises you can try, certified personal fitness trainers Cheryl Russo, Mark Westrich and Karulf demonstrate the 10 most common core exercises for all-around strengthening at every level.

Basic Plank

How to: With straight arms, place your hands directly under your shoulders, spreading your fingers wide like a fan as you push into the floor. Draw the belly button toward the spine to protect the lower back, as you straighten one leg, then the other until you are at the top of a pushup position. Retract the shoulders, keep the body straight, pushing the ribs toward the ankles to engage the core. Look six inches forward on the floor to keep your head in line with the spine. Don't let the hips rise up like a camel or drop down like a cobra.

Modified Plank

How to: Follow the same description as the traditional plank, except with the forearms on the floor parallel to each other, forming the number 11, with the elbows under shoulders.

Side Plank

How to: One arm is straight with the hand in line with the shoulder, fingers spread like a fan. Hips are stacked in line with one leg on top of the other. The belly button is drawn toward the spine to stabilize the core muscles. If you need more stability, stagger the feet. Hold the plank for 10 to 30 seconds on each side, depending on your fitness level.

In side plank, the challenge happens by adding on levels, not necessarily time. As you advance in your strength, you can raise the top leg, raise the arm, drop the hip down and up or add a dumbbell.

Bird Dog

How to: Begin on all fours with your hands directly below your shoulders and your knees directly below your hips. Engage your core and bring your belly button toward your spine. Slowly extend your right arm forward and your left leg back as far as you can, holding for a brief pause at the top. Bring the arm and leg back to the starting position and then repeat the same motion on the other side using the left arm and right leg. Make sure that you begin in proper alignment, and try to maintain a straight line from your head to your spine. Keep your core engaged throughout and do not let your back round or your pelvis or back rotate. Try for two to three sets of 20 reps on each side, depending on your fitness level.

Single-Leg Bridge

How to: Start by lying on your back with your knees bent and your feet flat on the floor. Straighten one leg, raising it up toward your chest until your leg is at 90 degrees. Driving through the opposite heel, lift your hips toward the ceiling and raise your glutes off the ground. Perform 12 to 20 reps and then switch sides. Repeat two to three times.

Alternatively, you can try an isometric version of this exercise by holding the bridge at the top position for 30 to 45 seconds for three sets on each side.

Twisting Crunch:

How to: Lie on your back with your knees bent, feet flat on the floor and your hands behind your head. Using your abs to crunch up and pull your shoulders off the ground, rotate the body and bring your elbow toward your opposite knee. Twist and repeat to the other side. Remember to keep a space between your chin and your chest, exhaling as you lift up. Try not to pull with your hands, but rather use them for support, and maintain proper spine alignment by looking directly toward the ceiling. Aim for three sets of 10 reps on each side, 20 reps total.

Kneeling Rollouts With a Ball

How to: Start with forearms on an exercise ball and knees on the mat. Your back should be flat and your stomach pulled into the spine. Breathe in as you roll out to your elbows and breathe out as you roll back to your forearms. Perform anywhere from 10 to 20 reps and repeat for two to four sets.

Back Extensions on a Ball

How to: Start by draping your body over the ball, feet spaced wide with your stomach on top. Breathe out as you raise the upper part of your body off the ball by squeezing your glutes and lower back. Keep arms long and draw them up, pulling your shoulder blades down and back. Perform 10 to 20 reps for two to four sets.

Criss-cross

How to: Start lying on your back with knees bent directly above hips in a tabletop position. Place hands behind your head. Breathe in and out naturally as you bring right elbow and shoulder off the ground toward the left knee while extending the right leg straight out, hovering above the ground. Do not bring knees past your hips. Keep your stomach drawn in and back flat against the ground. Twist to alternate sides. Perform 10 to 20 reps slowly for two to four sets.

Jackknife With a Ball (Advanced)

How to: Start in plank position, hands on the mat with shoulders directly above them, stomach pulled in and toes on an exercise ball. Breathe in as you pull the ball toward you, drawing your stomach in and pushing your rear end to the ceiling until you are in a pike position. Breathe out and return to the starting position. Perform 10 to 20 reps for two to four sets.