A speed bag is an item that is frequently used in boxing training. Its purpose is to improve a person’s reflexive speed and coordination by using repetitive punching motions. The bag itself is generally about 1 or 2 feet in diameter (0.3 to 0.6 meters), and it is normally hung from a short spring. Each time the bag is struck, it rebounds with a force that varies depending on how hard it was hit. If it is struck more forcefully, it will come back faster, and this is used in the training process.
Speed bag exercises generally involve the boxer standing in front of the bag and striking it with repetitive patterns at a certain speed and power. By keeping all the movements and levels of force precise, the boxer can generate an exact predictable rhythm. Boxers usually begin training with the speed bag by doing everything very slowly with small levels of power. Over time, they gradually increase power and speed until the bag is moving at a blur.
This training can help a fighter punch more quickly and with more precision. It also helps with timing. During a fight, an opponent will generally be a moving target, and catching him with a punch as he approaches requires that the punching motion be thrown in good rhythm with his movements. Using speed bags can potentially help improve a fighter's skill in this critical area.
Use of a speed bag can also improve a fighter's defensive skills. Catching an incoming fist is generally not that different than catching the bag as it swings wildly. This general level of precision and overall improvement of hand coordination makes this training a popular option for many other sports besides boxing. For example, a tennis player or a baseball player could both benefit from the enhanced coordination they might gain during speed bag training.
There are also fitness benefits to training with a speed bag. It can be very taxing to strike the bag at full speed, and it will eventually begin to build the muscles in a fighter’s arms. The bag can also make a fighter breathe more heavily and increase the heart rate. After performing the actions for several minutes, a fighter can potentially improve his endurance. Even though the speed bag workout is more like a sprint than a jog, if it is performed for more than 10 or 12 minutes, it can become a bit of an aerobic workout and potentially burn some fat.