Adjustable-Arm Cable Machines
Credit: Courtesy Keiser

Cutting-edge cable machines like those made by Life Fitness or Keiser are adjustable in so many different ways that you can dictate almost any movement path you can imagine, many of which are impossible with other machines or even free weights. "It's like we put a weight in your hand but allow you to control the direction of the gravity pulling on it," says Greg Highsmith, director of product development for Life Fitness. Engineers have managed to make the mechanical system almost invisible. Variations in lift ratio – how many inches the weight moves for every inch you move the handle – are another huge advantage.