I'm with Moja, i'd expect a dig if that age to be feelin it next day, especially if she's not at it constant.
If she was mine i'd give her meals a little sloppier a day or so before and i give tomatoes, with tinned sardines, at least once a week but thats just me...
If her grubs good then it's just down to fitness at the end of the day and though you can excercise em to death nothing beats running/work fit.