Increasing Core Strength

Our friends in the Pilates world have long known about the importance of core strength, but it's a term that becoming more and more widespread in the yoga community. The core refers to the muscles of the torso, both front and back, which support your spine, affecting your posture, and integrate the workings of your upper and lower body. While many workouts approach the abdominals in a fairly superficial way, yoga positions can get deep into your midsection, working muscles you didn't even know you had, which is great for your long-term fitness and health.

Forearm Plank:

Step by Step
Start in Dolphin Pose, knees bent. Then walk your feet back until your shoulders are directly over the elbows and your torso is parallel to the floor.
Press your inner forearms and elbows firmly against the floor. Firm your shoulder blades against your back and spread them away from the spine. Similarly spread your collarbones away from the sternum.
Press your front thighs toward the ceiling, but resist your tailbone toward the floor as you lengthen it toward the heels. Lift the base of your skull away from the back of the neck and look straight down at the floor, keeping the throat and eyes soft.
Stay anywhere from 30 seconds to a minute. Then, release your knees to the floor with an exhalation.


Full Boat:

Step by Step
Sit on the floor with your legs straight in front of you. Press your hands on the floor a little behind your hips, fingers pointing toward the feet, and strengthen the arms. Lift through the top of the sternum and lean back slightly. As you do this make sure your back doesn't round; continue to lengthen the front of your torso between the pubis and top sternum. Sit on the "tripod" of your two sitting bones and tailbone.
Exhale and bend your knees, then lift your feet off the floor, so that the thighs are angled about 45-50 degrees relative to the floor. Lengthen your tailbone into the floor and lift your pubis toward your navel. If possible, slowly straighten your knees, raising the tips of your toes slightly above the level of your eyes. If this isn't possible remain with your knees bent, perhaps lifting the shins parallel to the floor.
Stretch your arms alongside the legs, parallel to each other and the floor. Spread the shoulder blades across your back and reach strongly out through the fingers. If this isn't possible, keep the hands on the floor beside your hips or hold on to the backs of your thighs.
While the lower belly should be firm, it shouldn't get hard and thick. Try to keep the lower belly relatively flat. Press the heads of the thigh bones toward the floor to help anchor the pose and lift the top sternum. Breathe easily. Tip the chin slightly toward the sternum so the base of the skull lifts lightly away from the back of the neck.
At first stay in the pose for 10-20 seconds. Gradually increase the time of your stay to 1 minute. Release the legs with an exhalation and sit upright on an inhalation.

For more information:
http://pilates.about.com/od/historyofpilates/a/JPilates.htm
http://www.yogajournal.com/poses/finder/browse_categories