Dumbbell - Types

Types

By the early 17th century, the familiar shape of the dumbbell, with two equal weights attached to a handle, had appeared. There are currently three main types of dumbbell:

• Adjustable dumbbells consist of a metal bar whose centre portion is often engraved with a crosshatch pattern (knurling) to improve grip. Weight disks (plates) are slid onto the outer portions of the dumbbell and secured with clips or collars. Shown to the right is a "spinlock" dumbbell, whose ends are threaded to accept large nuts as collars. Alternatively, a dumbbell may have smooth ends with plates being secured by a sprung collar. Nowadays, many commercially sold dumbbells are available with sophisticated, and easy-to-use methods for weight increments adjustments.
• Fixed-weight dumbbells are weights created in a dumbbell shape. Inexpensive varieties consist of cast iron, sometimes coated with rubber or neoprene for comfort, and even cheaper versions consist of a rigid plastic shell that is filled with concrete.
• "Selectorized" dumbbells are adjustable dumbbells whose number of plates (i.e. weight) can be easily changed when resting in the dumbbell stand. This is achieved by adjusting the number of plates that follow the handle when lifted, e.g. by turning a dial or moving a selector pin — rather than manually adding or removing plates. This makes it very easy to change the weight of the dumbbell between exercises, and the stand typically doubles as storage for the additional weights not being used for a particular exercise.