Nope. A ‘bucking strap’ can be attached at the little side rings of saddle! For sure you are not supposed to hold to it when riding!
But actually, I’ve seen lots of people having it…
Not to confuse with a western bucking strap that makes horses buck in rodeo!
http://z.about.com/d/philadelphia/1/5/r/x/4/cowtown_rodeo_009.jpg