This test needs to be filmed, so have a friend on hand to film you or set up your phone.
Instructions:
For the warmup: Perform a thorough full-body warm up. Perform 1-2 sets of 3-5 pull ups on a bar at a moderate velocity.
For the test: do pull-ups on a bar as fast as you can. For each rep, start from a dead stop, and pull up as hard as you can. Hold the top for a brief instant, then lower at a normal rate. You can tap the floor in between sets, but do not push off with your legs.
When you feel that your initial velocity has dropped 10%, perform 1-2 more reps. Usually this is within 4-6 reps, so you should do 5-8 total reps.
Send the video to me for review & discussion.