Originally posted by Ben_Edict I don't think your conclusion hits the point. Your examples are poorly focused. That is the main issue. The fence is sharp, not the kid, the blinds are in focus, not the kids. That is the issue, you should address.
I agree with Ben, focus is off. Until that's resolved, you won't have sharp photos. How is your auto-focus set? Are you letting the camera choose the focal point, or are you doing it? I use either Center Focus and Recompose or manual focus. I would never let the camera choose the focus point, and moving the focus point around to various locations seems a waste of time to me.
Note, it is possible that your lens or camera is back-focussing. That needs to be eliminated as a possibility. I like this chart for checking AF:
http://focustestchart.com/focus21.pdf
I would also go into each of the three K-7 menus and reset to factory defaults. That should bring back some punch to your photos. If you don't like the look, customize the Image Tone settings for contrast, sharpness and saturation until you are happy with the result.
Keep the shutter speeds high with moving kids.