I would disagree with the premise they did not compete. They competed very hard every day because they had each other to compete against. His premise was he didn't want a watered down version of tennis. He wanted them to compete but against equal competition or better. I've been told that they leave out a part of the story that he would pay professionals to come in and compete against them . If you could compete in a closed environment you would not need to go outside that closed environment to compete. If I had a couple of sons the same age or a group of guys who were compelled to work equally hard I would have never had to go play travel ball. You could go pitcher against hitter and vice versa but that world does not exist in baseball like it does in tennis. He had the perfect world. He may have never yelled but he used other things that were just as bad in real life.
I agree. Being two sisters who were super good was a big advantage as they could play a very good opponent every day.
I think without that sister competition aspect not playing tournaments would have worked less good.
I also read an interview with a former top coach who had worked with male and female speed skaters who said that generally girls like the process of training more while boys generally get bored from training a lot when they can't play competitions, they train to win.
He said his girls worked harder, complained less and could tolerate more training but would be less competitive and enjoying competetion less.
Maybe that is a bit sexist as this was a former east German coach but maybe there is a bit to that, in my experience with the boys I work with they tend to get bored if there is no competition, they don't train to get better long term but they train to win tomorrow and you have to balance training and competition in a way that they improve long term but also win tomorrow or they are losing interest in it.