The serious injury will come to her next year.
This is a rule of WTA, after a crazy amount of tournaments year, it is fate.
Young girls have to learn how to protect themselves, and to enlong their life of sports.
Some players prefer to spend hours on the practice court while maybe a player like JJ prefers to use the tournament environment as practice. For all we know she spends less time on a tennis court than other top ten players. It's a balance. One thing is certain: she has learnt how to win.
You can't do that grinding away on a practice court for 6 hours a day.