The speed bag (or speed ball) is a small ovoid-shaped air-filled ball. It is hung from a platform by means of a swiveling pivot.
The speed bag is meant to be struck lightly and repeatedly by a boxer. It rebounds against the platform and back towards the boxer after each strike.
Proper use of the speed bag is meant to train the boxer to keep his hands up, improve hand-to-eye coordination, build hand speed, and when moving around the platform is thrown into the routine, about shifting weight while hitting on the move.
The speed bag is meant to be struck in rhythmic, circular motions from a high guard position. Ideally, the fist should come down in the middle of the downward slope of the bag. Depending on the size of the bag, this ought to be on a line with the area between your chin and your eyes. The hands should then return to the high guard position. Therefore, the bag platform should be adjusted to this height.
Even though the speed bag is a light, air-filled device, the repetitive striking motion can still be damaging to the hands. At a minimum, hand wraps should be worn while training on the speed bag.
The speed bag platforms that are frequently found in boxing gyms are adjustable. The same is true for a home gym boxing set up with multiple, built-in stations. However, there are many inexpensive kits that are simply bolted to the wall and are not adjustable. If one of these is purchased, careful measurements should be taken before installation, and obviously the use of the platform will be limited to the primary user.