Barbell. Dumbbell. Kettle bell. Whence 'bell'?

So, a barbell is a metal bar with weights on each end. A dumbbell is similar, but sized for one hand. A kettle bell is an iron ball with a handle.

Why do all of these exercise tools have the word ‘bell’ in their name? Is there some meaning of the word ‘bell’ other than ‘metal object that goes ding or bong’?

From the OED on dumb-bell: “Formerly, An apparatus, like that for swinging a church-bell, but without the bell itself, and thus making no noise, in the ‘ringing’ of which bodily exercise was taken.” So, dumb=mute, bell=bell. Barbell by extension, I guess. I’ve never heard of a kettle bell, but wikipedia says it’s also used for exercise, so “-bell” must have gradually come to mean “metal thing you lift for exercise.”

Here’s a promotional site about kettlebells.

So, if there were a political scandal involving freeweights, it could be called Bellgate.