The physical side includes menial service of the teacher and the yoga, but in yoga, the central drive must be for transcendence. Without that, it is not yoga but a personal or social activity of some kind. There are those who believe that there is a sort of side entrance: for instance that they can somehow attain by slavish service.
Again, the rich may hope to bribe their way in, the scholarly by study of texts, the eloquent by preaching, the busy by organizing. Such attitudes are big obstacles, and nearly everyone has to get round one or two of them. The yoga is very little physical: in fact, there is simply the basic requirement of a reasonable level of health so that the practices can be done. Later, yoga practice itself creates inner energy and light, which can be almost independent of the body state.
Dr. Shastri often pointed out that Saint Francis, already gone blind, was old at 45, so that he could hardly walk. ‘Without, a collapsing physical vehicle, but within, blazing with light.’