I am a marathoner, and, with quite a bit of training and working up to longer distances, my ~2 y.o. is now my running partner! While I do love running with her, I live in the midwest, so running in the winter isn't always feasible (It is currently -2 degrees F). We normally shoot for 40 miles/week (less in the winter). She is now in such good shape that even a longer run (12-13 miles) doesn't wear her out. Does anyone have any other exercise suggestions besides running that will leave her tired? It's sometimes hard to deal with her when I'm winded from a run and it made almost no dent in her energy level.