At the end of each lesson's beginning warm-up period, Sensei calls out, "Two lines for ukemi please!" And all the students answer, "Onegaishimasu!" We then form two lines and proceed to do rolls down the length of the dojo. As we reach the end of the mats, we file back to the head of the line and roll again; once forward on the left, once forward on the right, once backward on the left, once backward on the right, twice jumping over a person kneeling halfway down the mat. That might be all, unless Sensei feels that we need more ukemi practice, and he dispassionately watches as we stagger dutifully back up to the head of the lines.
I hate ukemi.
Apparently I'm not the only one. Here are a few definitions from the Aikido FAQ
Aikido: (1) The art of unity with the ground. (2) The way of blending energy. The Aikidoka (one who practices Aikido) attempts to become one with the mat by being thrown into it repeatedly in the hope that they will merge with the mat. This usually doesn't happen, so the process must be repeated. Frequently.
Ukemi: (1) The art of blending with the mat--part of what Aikidoka study. (2) The art of hurling yourself at the Earth for no good reason.
Nage-waza: The art of helping others to blend with the mat--the other part of what Aikidoka study.
Shodan (male): A male who is so adept at blending (and helping others to blend) that he can wear a skirt to class and nobody in class will laugh at him because he might help them learn to blend with the mat--at high velocity.
One reason that I hate ukemi is that I'm not very good at it. I am such a big guy (6'5", 280 lbs) that I carry a lot of momentum. My forward rolls can scare my Sensei. After two backward rolls I am so dizzy that if I don't sit seiza for a few minutes, I'll loose whatever is in my stomach. So I begin my study of techniques in a state of dizziness and mild nausea.
Why do I continue? As Oscar Medina says:
Ukemi is the actual vehicle through which you learn Aikido. Most Americans have difficulty with this concept, believing that you learn the techniques of Aikido by performing them as nage [one who throws]. Nothing could be farther from the truth. What you receive through your body as uke [one who is thrown] is not the losing end of someone else's execution of an Aikido technique. What you receive is the essence of Aikido itself. Bit by bit, your body and senses are learning the movement and energy of the technique as it is being done to you. You are learning what feels strong and right, and what does not. Aikido is thus transmitted directly from body to body. In order for Aikido to become effective, you must develop within yourself "good one point", "ki extension", the ability to maintain "weight underside" and "remain relaxed" throughout the waza. All four of these items are developed through ukemi rather than through doing the waza. As your skill at ukemi improves, your ability to perform the techniques of Aikido will likewise improve. They are directly linked.Sigh.
So I continue to hurl myself at the ground, "for no good reason."