“The primary reason for this was that Nautilus equipment allowed the health club (at the time known as the “health spa”) industry to offer to the general public a thing which had been previously unavailable. Prior to the invention of Nautilus, if a member wanted to train hard, in a more elaborate way than Universal equipment permitted, he had to learn how to use barbells. Someone had to teach him this. Moreover, someone had to teach the health spa staff how to teach him this. Such professional education was, and still is, time-consuming and not widely available. But with Nautilus equipment, a minimum-wage employee could be taught very quickly how to use the whole circuit, ostensibly providing a total-body workout with little invested in employee education. Furthermore, the entire circuit could be performed in about 30 minutes, thus decreasing member time on the exercise floor, increasing traffic capacity in the club, and maximizing sales exposure to more traffic. Nautilus equipment quite literally made the existence of the modern health club possible.
The problem, of course, is that machine-based training did not work as it was advertised. It was almost
impossible to gain muscular bodyweight doing a circuit. People who were trying to do so would train faithfully for months without gaining any significant muscular weight at all. When they switched to barbell training, a miraculous thing would happen: they would immediately gain – within a week – more weight than they had gained in the entire time they had fought with the 12-station circuit.
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.
Barbells, and the primary exercises we use them to do, are far superior to any other training tools that have ever been devised.Properly performed, full-range-of-motion barbell exercises are essentially the functional expression of human skeletal and muscular anatomy under a load.“
From Starting Strength by Mark Rippetoe