What are those black bands some players wore yesterday? (coaches, professional, sport)

[no kudzu]

I think Carder had at least 3 on each arm and quite frankly they looked tight. What are they for?

[dohmixer]

Here's a good answer I found with google search. Why are football players, both college and professional, now wearing black arm bands? Not the wrist bands, but what looks to be rubber bands almost, around their biceps? | Answerbag
In actuality, the bands were originally being worn under recommendation of the sports medicine teams for both NFL & Big 10 schools about 10 years ago in aid to help prevent tendinitis. It never actually worked effectively for that because the bands would need to be applied very tight almost like a tourniquet to provide counter-traction and prevent inflammation. So they were then discontinued.
However, during their use, as more and more of the players began to wear them, they actually became a focal point for the quarterback to see the receivers arms. So coaches began advising their use again. If you observe closely, you will see that it is mostly the offensive receivers that wear them now as focal points. Plus they are now the "in-thing" like tattoo'd biceps so a lot of it is just for show these days.