The 1980's were a fantastic time for gymnastics and that's when I got my start. I can't imagine that any sport has ever evolved so quickly and dramatically--if only one or two girls in the world were doing a certain skill in 1981--say, a full-in on floor-- it was practically compulsory by 1989.
If you've seen old bar routines from the past, you've noticed the gymnasts beating the bars--not out of frustration, but in a skill known as the belly beat. This is where you're swinging on the high bar, and you slam your hips into the low bar, pumping your legs to build momentum to swing back up. One thing I can tell you about belly beats: they required very, very, VERY precise bar settings.
I began gymnastics in 1984, and the routines for that four year olympiad cycle still had close bar settings and belly beats. A length of foam was wrapped around the low bar and fastened with first aid tape--you could slide it into place for practice or off to the side when you didn't need it. This allowed a bit more practice with less bruising. When you didn't use the foam, you better make sure your bars are exactly right--too close and you bruise your hipbones, too far and you hit your thighs and can't bend enough for the upswing. Arms too far apart or shoulders not extended would change the length of your torso and you'd hit on your thighs. But if you hit just right, it was totally painless and really fun.
For meets, the first thirty minutes were allowed for general stretch and bar sets. Because gyms would have different brands of equipment, every coach had to let each girl hang still with their hips draped over the low bar while they made adjustments and then noted on a clipboard the measurements of low bar, high bar, and center. This could take a long time at a meet full of young kids!
But gymnastics evolved SO quickly in this time frame that before the four years was up, beats were obsolete and they removed the beat from my compulsory routine Class III routine rather than waiting for the new cycle of routines. Bar routines have gotten much more difficult now that gymnasts can swing, fully extended, without hitting the low bar. But are they more interesting? Probably not. Check out Ma Yanhong who was still beating the bar with pretty amazing results in 1984. (Also, her dismount is Cra. Zy.)
Footnote: I can't let this post past without mentioning my favorite story from my coach: once she saw a girl in a meet who was too nervous to leave the floor to go to the restroom before her turn. And when she beat the bars, she peed everywhere. :D