research

http://www.youtube.com/watch?v=deT_f6vcFfs

I found this video of a toddler running and its done in a way that looks animated. In it you can see how floppy their hands are and how little their legs are and they move their legs a lot for the amount of ground they cover. 
I found another video in which you can see what the toddler looks like running from a side view, I used this as reference for my run cycle but it didn't look quite right so I decided to rotoscope the simple body shape/ bone structure so I can put my character over that and it will look more believable.
https://www.youtube.com/watch?v=XY3A8nPYL-c