They say swimming is the best exercise you can do. I would imagine that if she swam 15 to 20 minutes a day, with a good walk and run along with it, she would be in great physical shape. I have seen some pitbulls that can swim with the best of breeds, but in general there high muscle and bone mass in combination with low body fat makes them less boyant than other breeds; so in the water they struggle a little. Great exercise nontheless. She looks like she enjoys swimming.