Take a number between 30 to 50 and do 1 push up, 1 sit up. 1 leg raise, 1 squat that number of times. The purpose of the drill is to move from drill to drill with efficient and relaxed movement and pay extra attention to the neck and head so you learn to relax your body while working. The effect and benefit will be much greater than doing them all in repetition in terms of movement development.
Another drill to consider is to stand with your arms outstretched in various ways and moving with tension in the arms and have a partner hit the arms with a stick so you learn to relax the shoulder and rest of the body so the rest of the body is not affected. This is a good drill to teach relaxation during strikes fast. The striker learns that hitting the soft with hard (muscles with stick) is more effective and less destructive than other work (most of the time)