There are still similarities between walks and runs:
Walk, Run
(These are from Richard Williams Animation Survival Kit book, by the way. It's ~30-40$ on Amazon for the 2009 edition)
There's the basic contacts, passing positions, down's and ups. The difference for a run seems to be that only one foot is on the ground during contact, the character leans forward more, and frame 6 shows the character momentarily airborn, along with a few other subtleties. Try to copy this basic run cycle and see what you get. Try to figure out why it's convincing, then start experimenting with poses and see what you can do.
Walk, Run
(These are from Richard Williams Animation Survival Kit book, by the way. It's ~30-40$ on Amazon for the 2009 edition)
There's the basic contacts, passing positions, down's and ups. The difference for a run seems to be that only one foot is on the ground during contact, the character leans forward more, and frame 6 shows the character momentarily airborn, along with a few other subtleties. Try to copy this basic run cycle and see what you get. Try to figure out why it's convincing, then start experimenting with poses and see what you can do.