I think the problem people have is that they see skinny gymnasts but don't see that these gymnasts have great upper body strength (due to a very high power to weight ratio).
Watch and you will see that the gymnast makes the bodybuilder look like a complete amateur. So if a bodybuilder cannot do it, just imagine how horrible you would be trying to do the same activities. With lots of training the bodybuilder would eventually be able to do all the gymnast activities - and so can you. It is really just a matter of conditioning and training your body.