Take a look at this presentation on periodization. On page 15 it shows a chart of training volumes for different sports for 2 different decades. It shows gymnasts did less preparation through the 90's than in he 80's.
Explanation?
Gymnasts train less than they used to?
Started by Neal Winkler, December 30, 2010 · 1 Replies · 1,881 Views
You also need to look at the competition chart a slide or two later.
Together they show that more simultaneous training of elements leads to lower performance. By doing block periodization, the overall training is less, but due to the residual effect, performance in competition is better, and number of competitions and athlete can attend are more.