Literally the meaning of mudras is a seal. It is called so because it seals the mind with the soul.Exercises falling under mudra are associated with retention of breath.In fact bandhas and mudras go together.Mudras control the vital forces(pranas) and there by the mind in order to awaken the hidden mystic powers.
Once the potentialities of the spirit are unfolded before the performer,he can conquer all diseases and move towards God-realization.
Mudras help the striver to awaken kundalini to check the distractions of the mind and to sublimate vital energy into ojas shakti or spiritual energy.With the help of this shakti he can explore the mysteries.
Once the yogi attains spiritual energy,his personality blooms;he is able to attract men,his will power becomes strong and his mind balanced.
But in order to draw maximum benefits of Asanas,Pranayamas,Bandhas,Mudras and Kriyas,one must purify heart by selfless service of humanity and by developing virtues such as non-violence,truthfulness,purity,etc.Mere performance of any Hatha yoga exercise will not lead to attainment of powers.
There are scores of mudra that are in Vogue and practised,But we will here deal with only important ones.
They are Maha Mudra,Maha Vedha,Yoga mudra,Viparita Karani Mudra,Yoni Mudra,Unmani mudra,Kaki Mudra,Ashwini Mudra,Matangini Mudra,Khecheri mudra,Shakti Chalini mudra,Vajroli Mudra and Shambhavi Mudra.
Mudras,unlike other asanas,need concentration of mind towards the self or spirit.It is through these that man goes near to God.They help a man acquire psychic powers.But more important for man is to develop purity of mind.
The self is the source of all powers.There is nothing impossible for the self .It is the support,sustenance and final goal of all.The powers of the Self reveal themselves through the medium of mind.As the mind attains higher degree of purity and concentration,the Self reveals itself in various powers.
One Should practice mudras on empty stomach and invoke the mantra Om.There are some asanas which should not be done with out the guidance of masters initially. What.What ever yoga one may follow,what ever path one may adopt,the powers of the Self are bound to reveal themselves.
The acquirement of powers becomes an obstacle or a temptation for those aspirants who are lacking in discrimination or aspiration for Self-realization.These Powers being mental in nature do not constitute the goal of life.
One must not come under the sway of the development of psychic powers,but when these powers develop one may use them,with dis passion,for the good of humanity.Use of any power or wealth aids the purification of the heart.
But the abuse or the misuse of it through greed and infatuation leads to sever consequences.
Our scriptures speak of eight ‘sidhis’ and we are told only the great Hunuman had all of them.
Anima: A yogi can render his body as small as he wishes.
Mahima: One may become as heavy or grow as large as one wishes.
Laghima: One becomes lighter than cotton fibres.
prapti: Approaching distant things bu extending one’s subtle senses.
Prakamaya: Power of realizing what ever one desires.
Vashittwa: Perfect control over all beings,objects and elements.
Ishitwa: Power to create.
Kamavasayitwa: Attaining Supreme satisfaction and bliss.
Mastery over hunger and thirst;hearing and seeing from a distance;going to any place with the movement of the mind;entering into other’s bodies; assuming any form according to one’s wish;death at will;companionship of Gods;infallible will;power of commanding all;knowing past,present and future;power of enduring the pairs of opposites(heat and cold,gain and loss,etc);knowing the minds of others;controlling the powers of elements;remaining ever undefeated.
Yes mudras has the ultimate powers to lead a person towards being a complete person.
All this information is from the Book Yoga( A complete book on yoga) By Swami Prakash Muni Ji