This Yoga stretch warms up your legs and strengthens your abdominals at once. It is likely the most widely used Yoga pose of any, and in fact is so well known that many do not know that it is in fact a Yoga asana.
One of the (many) excellent reasons to practice Yoga is its versatility and its adaptability. Leg Raises are recommended by doctors before and after childbirth, to those with ankle/foot injuries or who otherwise have difficulty performing standing exercises, and to those who have lost large amounts of weight and look to strengthen the muscles for appearance purposes, but who also need to work on the subsurface muscular structures for organ support.
INSTRUCTIONS
1. Lie on your back with your legs extended and your feet together.
2. Place your arms on the floor at your sides, with your palms facing down.
*Your arms should be straight, but your elbows should not be locked.
3. Tuck your chin toward your chest to lengthen your neck.
*Your shoulders should be relaxed and down.
4. Exhale and press your lower back into the floor.
Important: Make sure your lower back remains pressed into the floor throughout the exercise.
5. Flex your right foot.
6. Inhale and lift your right leg toward the ceiling.
*Keep your leg straight, but soft. Do not lock your knee at any point.
*Your leg should not move past a 90-degree angle with the floor.
7. Exhale and lower your right leg back down to the floor.
Use your mind: As you lift and lower your leg, press through your heel and visualize your entire leg lengthening. Keep the image of longer, leaner, fit legs in your mind's eye.
8. Repeat steps 6 and 7 from three to ten times.
9. Take a deep cleansing breath, and follow steps 1 to 8 for the left leg.
FOR THE BEGINNER:
To make Leg Raises easier, begin the exercise with one leg bent and the sole of your foot placed firmly on the floor. Keep your foot on the floor as you raise and lower your other leg. This modification also helps to keep your lower back pressed into the floor and protects the lower back muscles and spine.
Pregnant women and those recovering from injury should follow these beginner instructions as well, regardless of experience.
FOR THE ADVANCED YOGI
Once you feel comfortable raising one leg, you can perform the exercise raising both legs at the same time. As you perform this variation, remember to keep your lower back pressed into the floor and your shoulders relaxed. If you need extra support for your back, you can place your palms down under your buttocks.
Raise and lower your legs in a set of five to ten reps, doing from 1 to 5 sets depending on your comfort level.
Because this variation makes the exercise more challenging for the abdominals and lower back, those who are pregnant, recovering from surgery or injury or who have chronic back issues should proceed only after consulting with a medical doctor. As always, never stretch your body to the point of pain.
NOTES TO STUDENTS:
When you raise your leg in this exercise, your other leg may lift off the floor. Make sure that your other leg remains on the floor throughout the exercise. It is also important to make sure that you keep both of your hips on the floor throughout the exercise.
In order to avoid arching your neck, you need to be sure your chin is tucked down toward your chest, as outlined in step #3. This important to avoid possible soreness or even strain.
Raise your leg until you feel a comfortable stretch. Go as far as you can toward the 90-degree goal, but never push to the point of pain. Even if you are very flexible, do not reach beyond the 90-degrees. This puts a great deal of strain on your lower back, and furthermore throws it out of proper position and alignment. Injury of a long-term type could be the result.
Links to additional abdominal stretching asanas are at the bottom of this article.
Stay well, everyone!

