What is the purpose of the thin bands football players are wearing on their arms and legs?

Question

What is the purpose of the thin bands football players are wearing on their arms and legs?

Answer 1

on arms, black tape is normally a death in family,close friends, etc as stated above but what ones are on the legs, only thing i can think of are under the fold of the sock, tape, to keep the socks up???, never seen anything else, except tape around the knee for support or something, please explain!!!!

Answer 2

Keeps the muscles warm and its a nice look.

Answer 3

Sign of respect......There has been a death. Someone close to the player or team.