If you have ever practiced vinyasa flow in America there is a great chance that he is one of the teachers of the teachers you have practiced with.
Until he brought these practices to Pattabhi Jois and B.K.S. Iyengar most yoga was a very still practice it seems.
What was once predominantly sitting and being still became a very physical practice that allows us to actually get in really good shape while doing yoga.
Here is a great video of Krishnamacharya practicing you can see the similarities and some of the movements that we do.