Many students have been injured over the past couple of weeks.
Not from yoga asana.
But from extracurricular activities.
(During a conference in 2008, Sharath talked about the jogging craze he got involved in when he was young(er). He said it practically ruined his yoga practice, and advised, "No extracurricular activities." If you have extra energy after doing (an intense) asthanga practice, you should volunteer to help poor people, he said).
He was - is - right.
Students in my classes have been injured from:
-Doing the Limbo
-Running a Marathon
-Walking Down Stairs
At least they have lives outside of yoga (not the last one - that was me). But still.....
You should rest one day each week. You should not even stretch. In general, no other exercise should be done. Period. Because your body becomes very stiff if you do other exercise. Yoga is the opposite of other types of exercise. Sharath got into the jogging craze when he was 17, and Eka Pada Sirsasana (a leg behind the head pose) and Kapotasana were a struggle. He has struggled the whole time with his practice, especially since he had Rheumatic fever as a child - which affected his joints.
"You have to keep struggling, because once you get [it], there is nothing like this." You should have dedication and faith in the practice. The guru can only do so much. It depends on the students' dedication to the practice, and faith.
Read more about the conference where Sharath said this here.