Flexibility of the body, especially the spinal chord, and flexibility of the mind are interrelated. Flexibility of the mind means adaptability. Its opposite, rigidity of mind, is called ego. As ego puts stress upon the nervous system, it creates a rigid body. Yoga says that the flexibility of the spine and flexibility of the mind are interrelated. if you keep the spinal column flexible, you will have a flexible mind, and you will find that the flexible mind can do more work than the inflexible mind.
Have you ever seen a tree standing on the shore? Such trees are very strong, still standing after seventy, eighty or ninety years. When a sudden flood comes, they are completely uprooted and washed away because they are very rigid. When the floodwaters subside, the tall grasses are still there. The powerful flood waters could not wash them away. Why? Because they just bent with the flow of the waters instead of resisting.
The water could not do anything. However, the more powerful but rigid tree was uprooted. Grasses blow before the gale and again raise their heads to the mid-day sun. The proud giants of the forest remain stiff, not moving an inch, only to be rudely uprooted. The humble servant prostrates to all and goes on serving until retired by old age, while his unbending master is envied, only to be thrown in prison. But the ordinary servant goes on. For a spiritual aspirant especially, flexibility is necessary. Once the prana (energy) starts to increase, any resistance will prevent its free movement. So every morning you should practise your asanas, pranayama and mantra jape (repetition of God’s name).
Flexibility of the spinal column will allow the energy to flow properly, so that instead of going downward, it will go upward. It is just like water, which, in a gross state, flows downwards, but when in subtle form ( as in steam) it rises. In the same way, a flexible spinal chord will allow your energy to flow upward, past the lower centres and up to the higher centres. That is what is meant by the “ascent of kundalini shakti”.
The shakti, or energy, which is stored in your lower chakras, is called kundalini. It is like the spring in a watch, tightly coiled from being wound, so that when released, it makes the watch hands move. The energy is condensed it is potential. Kundalini is coiled up and lying in a dormant state for most of us. Through the performance of asanas and pranayama, it unwinds, releases and rises up to the higher centres. As it is stimulated, each centre or chakra releases a specific wavelength or energy stored in it like a battery. As you rise, the voltage increases. The lower chakras may have for example only six volts, but as you go up, you encounter ten, fifty, a hundred, a thousand volts. So, for spiritual evolution, it is important to raise the energy to higher centres. Now you can see the interrelationship between your physical body and physical-mental flexibility. We perform all the physical exercises to attain mental flexibility and to get the energy moving properly, removing blockages in the centres.
When the energy is moving properly, you are bound to become healthy, strong, and peaceful, radiation strength and vitality to your friends. Then, wherever you go, whomever you meet, all will draw energy from you; you will be the centre of attraction and everyone will want to touch you, to shake hands with you, to be with you. Even your mere presence will bring them energy and strength.