Exerpt from article "Art Of Waterbury":
"The simplest way to incorporate different planes is to use horizontal and vertical descriptions. In addition, within each horizontal and vertical plane are numerous variations. Let's use the horizontal plane with pressing movements as an example. I denote horizontal pressing exercises as dips, and all bench pressing variations from a 30 degree decline up to a 45 degree incline. Any pressing movement with an incline greater than 45 degrees becomes a vertical pressing movement. Obviously, standing overhead pressing variations are vertical in nature."