[C+C] Forward running sprite animation

[Zia]

I'm working on 8-frame run cycles for my characters. This is what I have right now:



I feel like the torso feels really stiff and the lower legs a little floppy, but I'm not quite sure how to fix that - or what else I should be looking at doing here. This is the first 8-frame animation I've done; previously I'd been doing 4-frame animations

[noriah]

I haven't done many walks from the front, so I'd start with reference.
This game has approximately the same size sprites as yours, and they have walks in multiple directions:
http://www.spriters-resource.com/ds/adventuretimehicwysog/sheet/55313/
This channel has lots of easy to use reference footage too:

The grid helps you tell which shoulder is higher, the angle of the hips, etc.

The torso feels stiff because you aren't moving/rotating it at all. The hips and shoulders rotate in opposite directions because they drive the arms and feet to swing in the opposite directions. You could imply a rotation by changing the shading on the torso. You could also move the belt buckle from side to side.
You might also have the head bob up and down on a delay to have it follow through.