Nautilus is a type of exercise equipment characterized by its circular, nautically shaped spiral pulleys. The cams, as these pulleys are called, were designed to vary the resistance throughout the exercise. While the Nautilus company once focused exclusively on resistance training machines, they now manufacture a line of aerobic exercise equipment.
The Nautilus story begins in 1948, when Arthur Jones, described as a self-taught exercise physiology student, began to question the efficiency of traditional barbell training. He developed a machine that improved upon the limitations of barbell training. The torso pullover, a machine that worked the upper abdominal muscles and the latissimus dorsi, was his first creation. It was introduced to the general public in 1970. Dr. Michael O'Shea put Nautilus equipment on the map in 1975, when he opened the Sports Training Institute in New York City. The gym, which only used Nautilus equipment, catered to athletes such as Billie Jean King, Martina Navratilova and John McEnroe.
The strength curve, a concept that describes the amount of force available at a given point of a contraction, inspired Jones' creation. The cam varies the resistance so that it correlates with the strength curve. During a biceps curl, for example, there is less resistance at the start of the movement, where the muscle is at its weakest, and more resistance at the fully flexed stage, when the muscle is strongest.
Nautilus machines are adjustable, with movable parts that align with the working joint of the exercise. Proper form on a Nautilus machine requires that the axis of resistance of the joint align with the center, or axis of resistance of the cam. During a lateral raise exercise, for example, the seat is adjusted so that the center of the shoulder is lined up with the middle of the cam.
Nautilus also makes an aerobic machine called the Mobia, which combines the walking features of a treadmill, the stepping movements of a stair-climber and the smooth, circular movements of an elliptical trainer. The machine comes with a chest strap that monitors heart rate, and a specialized nutrition plan.
Variable resistance is just one of the benefits of Nautilus equipment. Some of the machines facilitate rotary movement, which is not easily performed with a barbell. Nautilus machines also provide resistance in both the concentric and eccentric phases of the contraction. The muscles shorten during the concentric phase and lengthen during the eccentric phase. During traditional barbell training, gravity can easily take over during the eccentric phase. This does not happen on a Nautilus machine.
While the Nautilus company claims that the machines offer variable resistance according to muscle strength within the contraction, a study published in the "Canadian Journal of Sports Science" showed that the Nautilus leg curl did not accomplish this task. Lead author MA Pizzimenti reported that the machine did not adequately alter the load to suit the biomechanical capabilities of the hamstrings. Another study, published in the "Journal of Orthopedic Sports Physical Therapy" compared Nautilus exercise equipment with barbell training. Lead author MT Sanders reported that there were no significant strength or endurance differences between the Nautilus and the barbell training groups.