Meaning of the bell ringing during Bobsleigh?

[ManokAeDobo]

I'm watching the Bobsleigh competition during the Olympics and I notice that at certain turns or even at the push start, people are ringing bells or there's a bell sound coming from somewhere. Does this mean anything? Tradition? Trying to make the driver's lose focus? Any clarification would be nice.

 

[cherry_blossom_girl]

Cowbells are used in all events at the winter olympics, because it kind of hard to clap when you have mittens on : D