Exercise is usually good for constipation but you do need to drink a bit more water to compensate for the extra water loss..

I doubt that your DD is constipated because of you exercising however at her age you could introduce some water in a sippy cup. Also maybe try giving her some pears as well as her usual fruit. Bananas can be constipating for some children so if she eats them try dropping them from her diet for a while.