Yoga should ONLY be undertaken by a Physically Healthy & Mentally Stable Person. If in doubt you should see your G.P. or a Health professional for Diagnosis and / or perscription.
The Eight Steps
in hatha, radja & Ashtanga Yoga
1) Moral Commandments ( Yama ), Harmlessness ( Ahimsa ), truthfulness ( Satya ), Non-Materialistic ( Aparigraha ), Continence ( Brahmachanya ) and Non-Stealing ( Asteya ).
2) Rules for Purefication ( Niyama ), Purity ( Saucha ), of body and mind - which also means getting rid of the six Weaknessess. a] Passion ( Kama ), b] Anger ( krodha ), c] Greed ( Lobha ), d] Infatuation ( Moha ), e] Pride ( Mada ), f] Envy ( matsarya ). Contentment ( santosa ), Austerity ( tapas, study of the scripture ( svadhyaya ) surrender to the self at all times ( isvara pramdhana )).
3) Postures ( Asana ),
4) Breath Retention & Regulation ( Pranayama ),
5) Control of Mind & Senses ( Pratyahara ),
6) Concentration ( Dharana ),
7) Meditation ( Dhyana = prolonged concentration ),
8) Holy Trance ( Samadhi = condition of Blissful Beingness ).