Physically profficiant

During some of the classes we take in the semester there are a few students who I notice can not complete some of the critical elements. I feel if you are going to have to teach students why it is important to be able to complete the task in hand the teacher themselves should be also be able to do so. Some of the students in my class are unable to simply serve the volleyball over the net or complete a normal hit over to the other side during game play. Students will notice you are unable to o so and question the authority and wonder why they have to if you can't.