The leg motion looks really good but you need to work on the bob. The reason we bob as we walk is basic geometry, our leg is longer relative to the ground when it's straight than when it is bent so when the leg passes in the middle it pushes the body up from the hip. There isn't necessarily any movement in the spine, though there certainly can be if you're going for that look. The hip movement is non negotiable though unless you're really trying to push for a funny walk where the character bends their legs in a peculiar way.