Most people have probably seen a wooden dummy before. There is a famous scene in "Rumble in the Bronx" where Jackie Chan uses one in the beginning of the movie. But even though Jackie Chan's moves on the dummy are flashy and impressive, there is much more to using a dummy than just looking cool.
Wooden dummies ("mook yan jong" in Chinese), while primarily found in Wing Chun kung fu, can generally be adapted to any martial art style. The advantages that wooden dummies provide are numerous, and are not limited to:
Developing a powerful structure: When you strike the solid dummy you receive instant feedback regarding your structure. If your strike was solid and true and with good structure, you will feel the power transfer from your body into the dummy. If, for example, your wrist was at the wrong angle, you will receive negative feedback from the dummy.
Wooden dummies are available to train 24/7: Regardless of if you always train at the same time every day or if you train at odd times, a dummy is always available as opposed to doing drills with a partner where you don't have to set up a time that works for both of you. Another advantage to this is that wooden dummies can be used throughout the day, too; Perhaps you are going to train a specific technique every time you walk past your dummy, or every hour for the entire day (to build central nervous system efficiency, also known as "muscle memory" or "greasing the groove"). It would be difficult to find a training partner who would agree to that regimen!
Building power: While a dummy does not necessarily have to be used with full power, there is nothing wrong with doing so. Over time, as you build your speed and power on the dummy, you will eventually begin to develop tangible power in your strikes, which leads to the next point:
Building confidence: When you are able to strike with great force, and you know that you are able to strike with great force, your fighting ability will increase exponentially. The difference between being able to perform a powerful technique in the air and knowing that you can perform a powerful technique against resistance such as a dummy without getting injured is extremely empowering.
If you decide that your training would benefit from a wooden dummy, there are some things you should keep in mind as you shop for a dummy:
The body must be between 8.5 and 9.5 inches in diameter. The reason for this is to allow the upper arms to be placed at the correct angle. Any narrower than this and they will be too close together; any wider and they will be too far apart.
The arms: The upper arms must be set at the same angle. Some dummies have upper limbs where one is resting 1 or 2 inches above the other one. This is incorrect as it will develop imbalances in your techniques. On a properly made dummy, the arms will have offset shanks allowing the arms to rest at the same height despite the holes in the body being at different heights.
Training with a wooden dummy is an effective way to improve your technique, your power, and your confidence. Although it is traditionally used by Wing Chun styles, any style of martial arts can adapt its techniques to the dummy.