There has been a lot of talk in gridiron over the last 4 years about the importance on a strong neck and grip, and how a strong neck can help reduce the incidence of concussion.
i own a 4 way neck machine which is pretty good.
if you don't have a machine...
*for the front muscles of the neck, while lying on a bench you can use a small plate placed on the forehead
*for the muscles at the rear (trap's) shrugs are as good as any exercise
* for the muscles at the side! Manual resistance, Holding a towel that is wrapped around the head.
one or two rep's 10-12 is sufficient to build muscular strength, once a week.
some have found it more useful splitting the the four movements into two, like forward and back movement monday
side to side movement on a Thursday