There is a number of sources I'm referencing in my head, not exactly the same. Minions running was something I though would be close, but I'm thinking a little more hope between steps to get more distance out of very tiny legs.
and one of the best tutorials on HumanIK:
https://www.youtube.com/watch?v=-7E1OmvpbvI
audio is quiet but its good. Another one with good tips is:
https://www.youtube.com/watch?v=-7E1OmvpbvI
audio sounds distorted and low but whatevs, its also good!