Missing the bag. If you miss the bag with a proper linear technique, there will be no problem. If come up short with a circulate technique, there will be no problem. If you are too long with a circular technique, you may receive a serious injury. For example, a round kick that is so deep that the knee hits the bag or a spinning back fist that is too long and the elbow hits the bag. The result is a seriously hyper extended joint.
Bending the wrist. Keep the wrist locked for all hand techniques. If it is even slightly bent, it may collapse resulting in a serious sprain.
Holding breath. When people exert themselves, they tend to hold their breath. Watch people when they pick up something heavy. They take a deep breath, hold it, grunt, and lift. This reduces endurance by starving your body of oxygen when it needs it most and it may increase thoracic pressure enough to cause a blood vessel to rupture in a vital area. Exhale or kiai as you strike or kick to prevent breath holding and to enhance power by tensing the torso muscles.
Do not kill the bag. Trying to hit the bag too hard over-stresses the body and destroys the mechanics of the skills you are trying to develop. In addition to increasing the potential for injury, your strikes and kicks become slow, sloppy, and off balanced.
Do not get sloppy. Do it Right! Keep it Tight! Focus on staying relaxed, hitting with fast, powerful, technically perfect techniques. Always work on strikes and kicks that start from and return to a solid guard position. Sloppy bag work results in bad habits that will hinder rather than help your sparring.
Do not over train on one apparatus. Supplement your heavy bag training with training on focus mitts and Thai pads. The only problem with these items is that you need a training partner to hold them. With the heavy bag, you may work alone. Focus mitts are flat, heavily cushioned pads with a glove on the back. The partner wears the pads to provide moving targets for you to use to develop punching speed and precision. Thai pads are large pads that the partner wears on the forearms provide moving targets for strikes and kicks. Working the pads is similar to working on a heavy bag that can think and move. The advantage of this equipment is that there is less resistance on impact and therefore less strain on the body from striking them. They also allow a wide variety of training drills that help develop timing, distance, movement, and accuracy.
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