Art responding to Science:
Note that Bubba's subject is the mechanics of the spey cast, not the spey rod. Quanitfying what the rod does would be difficult enough, but the spey cast consists of interactions between the rod, the line (we'll mercifully ignore the leader and fly for now) - and you, the spey caster. Combined, it's enough to crash a Cray supercomputer.
I think that much of the appeal of spey-casting, though seldom expressed, is our immediate experience of the process. To me, after seven years, every successful spey cast seems like a minor miracle. Two dictionary references: Kinematics: in physics, the study of motion exclusive of the influences of mass and force. Kinesthesia: the sensation of bodily position, presence, or movement resulting chiefly from stimulation of sensory nerve endings in muscles, tendons, and joints.
Normally, making a spey cast feels good to your proprioceptors: special receptors in your muscles, joints, ligaments, tendons and inner ears, in much the same way that the first slow back-stretch after arising in the morning feels good. But that's a little off Bubba's subject.
Consider Mike Maxwell's casting style. Although he uses arms and shoulders somewhat less than most of us do, he makes maximum use of "body rock." It reminds me of some films I've seen of medieval catapults, which lurch backward and forward on their base skids while propelling boulders with slow, awesome power. Perhaps it's necessary to get the most out of Maxwell's very slow "true spey"-action rods. Mike, his rod and line are one kind of casting unit. Perhaps, therefore, a caster working a fast-action spey rod, and shorter-head line are a different kind of unit involving different body movements. :eyecrazy:
There, I've done my part. Someone else can do the math.
