Practice what you Teach!
Teaching Karate is challenging and it goes beyond the dojo; a good Sensei is teacher, mentor and role model to their students.
On a physical level, a Sensei must be competent at performing whatever technique he is asking his students to perform. As we get older we may not be able to maintain the same high level of competency but we must understand what we are teaching. To this end it is essential that we continue to practice to the best of our ability; irrespective of age.
So practice what you preach – better still, practice what you teach!