Chakrasana in Sanskrit, is also known as The Wheel. It takes its name because upon completion of this posture, it resembles a full circle of semi circle.
This pose opens up the chest by opening the thoracic region on the upper back. At the same time, it strengthens the gluteus muscles, the legs, calves, wrists, arms and spine. As it requires a strong core, it helps to strengthen the abdominal muscles as well.
In this pose, elbows are fully flexed, wrists are extended at 90 degrees, hips are hyper extended and lumbar is extended.

Sequence leading into the pose

  1. Lie on your back
  2. Bend the knees and place both heels close to the hips
  3. Place the palms firmly on the ground next to the ears with elbows pointing upwards
  4. The palm and heel of each side should be in one straight line.
  5. Inhale slowly.
  6. Continue to inhale and press the palms firmly on the ground.
  7. Raise your shoulder, chest, abdomen, hips and thighs above the ground.
  8. The neck and back should be arched with the crown of your head resting firmly on the ground.
  9. Exhale and inhale a few times while at this position.
  10. Take a deep breath.
  11. Press your feet and palms on the ground while holding your breath.
  12.  Taking the support of your hands and feet, slowly raise your head, shoulders, trunk, abdomen, hips and thighs to the optimum level.
  13.  Your head should be hanging in between your shoulders.
  14. Make sure the elbows are not bent.
  15.  Arch the body as much as possible, opening your thorax and taking the pressure off your lumbar.
  16.  Exhaling gradually, bring the lower part of your body down and return to the starting position.

Pose Modifications
One can choose to have blocks placed below the palms, or to lift up on fingertips as well as the balls of the feet.
The usual restrictions are limited strength in the triceps brachii muscles, the limited extension of elbows, limited flexibility in the thoracic region, spine, iliopsoas and rectus femoris muscles. For those who are not as flexible, the diaphragm is also another limiting factor in this back bending pose.
Theway to keep improving is to practice everyday with consciousness of each inhalation and exhalation, and in time to come, your elbows will be fully extended, the muscles will also be strong enough to lift you up.
The physical benefits of this pose are that it strengthens and increases the flexibility in the spine, wrists, thorax and hips. It also strengthens the muscles especially on the arms and abdominal region.
This back bending pose is also known to have a therapeutic effect on back ache sufferers (though we need to practice with caution and awareness) and asthmatic victims. As the body is bent the opposite manner, it also stimulates the digestive system and acts as a massager for our liver and pancreas.
I have my limitations on this pose at the moment, but I will persevere in my practice. There was a few times, during practice, when Master help lifted me up. For the first time, I breathed in so much deeper. I just wanted to stay in the pose while enjoying the deep inhalation and exhalation. Afterwards, I felt like my lungs are cleared and light. Breathing becomes easy and I feel so much lighter. I guess the other therapeutic effect it has is on the recovery of depression. When one is able to breathe deeper, the clouds in the mind clears.