First and foremost, there's no either/or trade-off between supportive parenting and demanding parenting. It's a common misunderstanding to think of "tough love" as a carefully struck balance between affection and respect on the one hand, and firmly enforced expectations on the other. In actuality, there's no reason you can't do both.
There is something to be said for Angela Duckworth's opinion, based on her grit research and displayed in her best-selling book, Grit: the Power of Passion and Perseverance. I say that because she agrees with my common sense approach to using balance in our methods.
"Fathers, do not provoke your children to anger, but bring them up in the discipline and instruction of the Lord."
"He who spares his rod hates his son, but he who loves him disciplines him diligently.
If you want to bring forth grit in your child, first ask how much passion and perseverance you have for your own life goals. Then ask yourself how likely it is that your approach to parenting encourages your child to emulate you. If the answer to the first question is "a great deal," and your answer to the second is "very likely," you're already parenting for grit.
Not only this, but in a separate chapter, the author describes the research we have about the effect of "extra-curricular" activities. Kids - who participate in organized, outside-of-school activities, with adults in charge, and endure for multiple years while making progress - tend to be more gritty than their less active counterparts.
The bottom line of this research is this: School's hard, but for many kids it;s not intrinsically interesting. Texting your friends is interesting, but it's not hard. But ballet? Ballet can be both.
The amazing part of her findings and opinion is that kids can develop their perseverance by following their passions. They can strengthen themselves by pursuing their interests.
Notably, the particular pursuits to which students had devoted themselves in high school didn't matter - whether it was tennis, student government, or debate team. The key was that students had signed up for something, signed up again the following year, and during that time had made some kind of progress.
I started this post with comments about balance, and I will end it the same way. Though I have not conducted my own psychological research, I also know that down time is important. Boredom is important, too. Kids need time to relax and reflect. They need time to dream and create. They need time to think for themselves. And they need time to be out from under the thumb of coaches, parents, and teachers. There is something to be said for free time in our children.