Scenic bios is the state of physicality that a performer generates in the act of performance. It is a state of readiness and energy that is above and beyond the daily. Daily energy is that which we all employ during ordinary activity. It is usually the minimum required for practical requirement. Extra daily energy on the other hand, is that which the performer employs by various means such as balance, anatomical alteration, and other less obvious devices such as extra awareness and understanding of certain principles, in the very act of performance.
Some of these principles, first recognized and formulated in empirical studies by Eugenio Barba, may be learned or they may be inherent. Such principles as equivalence, dilation, rhythm and timing, all seem like second nature, and the performer may not know that she is applying them in any strict sense. But, Barba has demonstrated that through physical training and exercises of his devising these principles can become fruitfully exploited by the actor in her endeavours.
All these principles are believed by Barba to exist in the actors pre-expressive being. This pre-expressivity is otherwise known as scenic bios, or stage 'presence'.