Ah, I can't seem to get it to work properly. Do I need to have the leg selected whilst rendering or the camera? I've got lost on the camera shutter open and shutter closed bit too as the manual isn't clear to a dumkopf like me. I've got frame 1 set at 0 for open and 1 for closed. This is the same all the way through the 16 frames. I'm using with his leg in  back position in 1 and 16 but at 8 well forward.

Feel like giving up! Can't even do motion blur.. (Oh, it is turned on in the Render settings, I did manage to check that!)