It is interesting to see that some teachers tell their students to work hard when the student is unable to do so. A student is breaking the wrist and the teacher is telling to do handstands/jumps inspite of this. Whereas, some teachers are telling their students that they are doing a great job while the students are developing big bellies.
There is something called Laziness. Some people think Laziness is in the body or body cells. Actually, laziness is in the Mind. And, when the body has enough mass, the Mind thinks that the body does not have any energy. But, that mass can be converted into energy and it should be.
However, there is something called Lack of Energy. And, this belongs to the Body. Whereas, some people think that is Laziness. Then, their own Rajas forces the Mind of the less energetic person to become more Rajasika. Because Mind is more powerful than the Body, the student wrongly increases the activity of the Body. Actually, the student should take rest in this case.
This difference between the Laziness and Lack of Energy, between the Body and the Mind, and between Tamas and Rajas should be clearly understood by a Yoga Practitioner.