Until she wins another major then all the coaches she has gone through are spot-on, When the going gets tough she will pull up, Many of the top tennis players play with pain and have operations for all sorts of things, I think it's a mental block with her after winning the US Open at that early stage of her career, She went downhill fast and troubles with many coaches says something was not right.
Once you win a major the hardest part is to repeat it, Doing the long yards fitness-wise and putting in the training and the hours and hours of hitting needs 100% dedication away from the lifestyle
Warm-up tournaments mean nothing really, all they are used for is playing time on grass for timing, Last week's loss in the final at Nottingham was down to a slip ?? 1 set up then play suspended and the next day taped up knee lost 2 sets and the final,
She needs to either want it and put in the hard yards or leave tennis for a lifestyle and live on winning the US Open, My bet is the 2nd option