Bakasana helps to strengthen the spine, the pelvic girdle and the legs and it also helps with physical balance. It also helps the circulation of the blood to the head as it falls into the inversion set of postures.
By performing this posture it allows lots of muscles to be in use at the same time - the hamstrings are both stretched and contracted, the forearm flexor muscles are stretched, the gluteus maximus muscle and the core stability muscles are also contracted.
As an inversion it helps on the mental and emotional level by releasing stubborn habit patterns. It creates a wonderful flow of energy through the spine activating all the chakras.
Although the benefits of this posture are excellent you need to make sure, as with all inversion postures, that if you are suffering from high blood pressure, have a hernia or a detached retina, have spinal disc problems or are pregnant then you should not do this posture.
It is really important when doing this posture, especially for the first few times, that you do not cause the hips to twist by over extending the raised leg. The guidance from a partner will help you, until you become more aware of the flat lower back when in the posture. Preparations for this posture include strengthening the gluteus maximus muscles and working on stretching the hamstrings.
How to do this posture?
Stand in the mountain pose. Place your hands flat on your thighs; breathe in and as you breathe out slide your hands down legs towards the floor making sure you are bending at the hips. Place both hands on the floor about two hand lengths in front of your feet (bend your knees if you need to).
Raise your right leg behind as high as is comfortable, whilst making sure the hips and lower back are flat and trying not to twist the pelvis (get someone to watch and check this for you until you can feel that you are in the correct position). Allow the stretch to extend from the hips to the toes.
Slowly lower the raised leg down to its original position. If this is uncomfortable you can always bend the knee and then place the foot on the floor.
Uncurl your spine raising up to Tadasana (mountain pose) before completing on left side.
The beauty of this posture is that even if you can't get your hands down to the floor you can use blocks to assist. You can also use the back of a chair or the seat of a chair. If you use the back of chair you just need to lift the knee, pushing the heel away behind you whilst holding onto the chair. If you use the chair seat for support, lift the knee and push the heel behind you. It is just as important to make sure the pelvis doesn't tilt when using any of these modifications.
This is an excellent inverted posture to do, especially if you are not comfortable with shoulder stands as it allows you to fully experience the magical effects of the energy of the chakras moving throughout the body whilst you are in total control of the posture. Have fun with this and try out with the modifications too.