Sure, duplicate the clip onto a new track above, mask the area you want to have shaded, and reduce the opacity of the lower clip to the desired level.
Alternativley, do the same but use the Cookie Cutter on the top layer, reduce opacity of lower layer to acheive the same.
To overlay an arrow, make a PNG file of the arrow you want with a transparent background. Import it and place it where you want it using track motion. You could even put the athletes name on the arrow if you want to. I used this technique in
THIS video to censor out a pair of boobs.