Dumbbell - China Ent Medicals Disposables - Disposable Vaginal Speculum Manufacturer
History
HistoryThe forerunner of the dumbbell was used in India for more than a millennium, shaped like a club so named Indian club. The design of the "Nal", as the equipment was referred to, can be seen as a halfway point between a barbell and a dumbbell. It was generally used in pairs, in workouts by wrestlers, bodybuilders, sports players, and others wishing to increase strength and muscle size.
Etymology
"Dumbbells" as a word originated in Tudor England athletes used hand-held church bells to develop the upper body and arms. These bells ranged in weight from a few ounces to many pounds. The bells were flourished in various ways. This would have made a great deal of noise, so the athletes would take out the clappers so they could practice quietly; hence the name "dumb", as in "no sound", and "bell" dumbbell. When strongmen started to make their own equipment, they kept the name, even though the shape changed. The etymology of the word "kettlebell" is similar. See Oxford dictionary definition.
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:
A spinlock adjustable 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.
Fixed-weight dumbbells are weights created in a dumbbell shape. Expensive varieties consist of cast iron, sometimes coated with rubber for safety.[citation needed] Cheaper versions consist of a rigid plastic shell that is filled with concrete.[citation needed]
"Selectorized" dumbbells are adjustable dumbbells whose weight is changed mechanically for example, by turning a dial or moving a selector pin rather than manually adding or removing plates. This can make it very easy to change the weight of the dumbbell between exercises. Such dumbbells often include stands that double as storage for the additional weights not being used for a particular exercise.
See also
Barbell
Kettlebell
Weights
Weight lifting belt
Pool dumbbell
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by: gaga