Yes the shape distortion makes it harder to track…
Regarding the imaging hardware, the ideal results would be obtained with
high frame rate - more frames means the shape will change less from frame to frame and has less chance to disappear outside the search window.
high shutter speed - will better stop freeze the moving object as opposed of creating the blurry shape you have in your video.
Control of shutter speed is generally the hardest to get as camcorders/cameras/webcams are built to create movies pleasing to the eye when played back, and so for the vendors the blur is actually a feature rather than a bug 
For the markers the plain circular shape you have is good. Avoid shapes that would not look the same when rotated, like a rectangle or a triangle. Another thing to experiment with would be to have another smaller circular disk, say half the size, inside the main one, with a contrasting colour.
The size of the target is also important, for that you can switch to the regular trajectory tool (right click in an empty area on the video), the inner rectangle is the actual target being tracked. The marker should take as much of its space as possible. (The outter rectangle is the search window).
Keep us posted with the experiments 
