“The reason that isolated body part training on machines doesn’t work is the same reason that barbells work so well, better than any other tools we can use to gain strength. The human body functions as a complete system – – it works that way, and it likes to be trained that way. It doesn’t like to be separated into its constituent components and then have those components exercised separately, since the strength obtained from training will not be utilized in this way. The general pattern of strength acquisition must be the same as that in which the strength will be used. The nervous system controls the muscles, and the relationship between them is referred to as ‘neuromuscular.’ When strength is acquired in ways that do not correspond to the patterns in which it is intended to actually be used, the neuromuscular aspects of training have not been considered. Neuromuscular specificity is an unfortunate reality, and exercise programs must respect this principle the same way they respect the Law of Gravity.” –Mark Rippetoe, Starting Strength (p. 3, 3rd ed.)
But MovNat is the general context for human movement. The book Body By Science (a system that utilizes exercise machines), is, from what I have heard, worth a read.