Essay: Bio-mechanics of Good Jujutsu

There is a general misconception that jujutsu is only effective if you possess a high level of strength, stamina and aggression and that without these elements you will never to able to overcome an opponent who is larger or stronger. However, by recognising the importance of, and making use of certain principles of bio-mechanics, you will find that it is possible to overcome even the biggest or strongest of opponents.

The art of jujutsu centres around using an opponent’s size, momentum and balance to your own advantage and slight adjustments in your own posture (tachi shisei) can greatly enhance the effectiveness of the technique being executed.

Relaxation

One of the simplest things to remember when executing a technique or movement is to stay relaxed, as when you 'tense up' this slightly raises your shoulders, arms, core muscles and leads to a raised central point of gravity (tandem). Staying relaxed allows quicker evasive movement and provides the slightest extra amount of time to fight back.

Breathing

Breathing is closely linked to relaxation. The breath must be kept slow and steady. We breath outwards when we are ending a technique, usually accompanied by a kiai. It may sound strange that such a simple thing can make a difference.

Using a simple wrist lock for example - when leaning in breathing out simultaneously allows us to exert more of our body's mass into the technique, making it more powerful. This is very similar to how a boa constrictor traps its prey, as with each exhalation the snake tightens its grip and makes it harder for the prey to escape.

Timing

Picking the right time to start to apply a technique or evasive movement can make tremendous difference in determining if you will be successful or not and reach the desired end result. If you move too early or too late your opponent will either have time to adjust themselves and complete whatever they are attempting to do, or you will not be able to get out of the way fast enough. Maintaining eye contact during this time will help you pick the optimum time as most people will signal their intent through movements in their eyes.

Breaking the Opponent's Balance

Once you have the opportunity to execute a technique, if your opponent's balance is not slightly off, it can be very hard to get the end result you are looking for. Applying the technique at the right moment allows us to manipulate their balance. Assessing the weight distribution in their legs and their centre of mass can help us to achieve this. Once their balance is broken we must keep it that way throughout the duration of the technique. They must not be allowed to recover their balance and posture.

Balance Combative Distance (Maai)

If you are too far away from the uke (person receiving a technique) it can be a positive thing as this will mean that you are safe from a potential attack. However it is important to be aware when this is no longer the case and you are within the reach of the attacker. When you are executing a technique, your proximity to the uke will have an impact on your ability to control them.

If you are able to keep in mind all of the above when practicing jujutsu, you will find that you do not need to rely too heavily on your own physical strength and the techniques you are practicing will feel easier to execute and feel more effective.