The Yogasūtras of Patañjali (200 B.C.) is accepted as a basic text of yoga and has been highly venerated. In the third chapter of the work called Vibhūtipāda, various vibhūtis or siddhis (supernatural powers) that a yogi obtains by the practice of ‘saṁyama’ are described; and balasiddhi is one of them. Saṁyama is a technical term used to indicate the triad of dhāraṇā (fixing the mind on the object of concentration), dhyāna (meditation) and samādhi (total absorption in the object thus chosen), practised on one and the same object. This saṁyama results in the development or manifestation of supernatural powers in the yogi.
If saṁyama is practised on the strength of an elephant (vide Yogasūtras 3.24) or lion or the mythical bird Garuḍa or Hanumān (the devotee of Rāma), the yogi develops a strength similar to theirs. This is called ‘balasiddhi’.