For resistance training, cable machines typically involve a system of pulleys and cables. Think of how people used to draw water from a deep well, using a rope, pulley and bucket. The cable runs through a pulley, or even a few pulleys, and connects to a stack of weights. Because the cable can be pulled in various directions, the machine can be used to work on different muscle groups. The cable machine doesn’t require as much balance as free weights, so you can concentrate on correct form and holding the peak contraction on each repetition.
How It Works
When you use a cable machine, you can apply force to a muscle from various directions, such as horizontally, vertically or diagonally. A freely rotating wheel, the pulley can alter the direction of force being supplied by the cable. The weight stacks consist of rectangular plates, each weighing 10 or 20 pounds. These stacks slide up and down guide rods. A horizontal hole has been drilled into each plate, so a pin can be inserted through the plate. This action establishes the amount of weight used in an exercise. You can attach any one of a variety of handles, such as a parallel-arm lat bar, short straight bar, double-handed low row bar, single-handed D-grip, V- or U-shaped press-down bar, rope or ankle collar, to the end of the cable.
In a fixed-resistance machine, the design or arrangement of cables and pulleys has been pre-set. You lift the weight stack by pulling on the handle attached to the cable. When you use a fixed-resistance machine, you’ll expend more effort during certain phases of the exercise due to changes in your muscle length as well as the angle of the pull. It’s as if someone is altering the amount of weight during the exercise. As a result, your muscles are not evenly taxed throughout the range of movement. You’ll feel the most resistance, or the maximum weight that you can move, where the angle of the joint is weakest. Strength training exercises on fixed-resistance machines include the bench press, triceps press and shoulder press.
The more common type of cable machine seen in gyms is variable-resistant. These machines feature a kidney bean-shaped cam or wheel. The way in which the cable routes over the crests and valleys of the cam affects the relationship between the weight stack and the axle, or the pivot point, on which the cam turns. When you reach the point at which the exercise becomes most difficult, the distance between the axle and the weight stack decreases and makes the weight easier to lift. On the flip side, the distance between axle and weight stack increases during easier phases of the exercise. By varying the distance between the fixed weights and the pivot point, you can work your muscles evenly throughout a complete range of motion. Variable resistance machines can be used for single-joint exercises to isolate particular muscles for a workout, such as bicep curls, or multi-joint exercises, such as an overhead press.
Check for worn pulleys, frayed cables, damaged welds and loose pads before you use any type of cable machine. Stop using the machine if your movement is rocky or rough. Adjust the machine’s pads and levers to suit your body size. Avoid sticking your fingers or hands into the weight stacks to pull out the selector pin or change the load. Use slow and controlled movement to exercise your muscles through a full range of motion. Don’t hit the top of the pulley on the way up or bounce the weights at the bottom of a lowering phase.
Kay Tang is a journalist who has been writing since 1990. She previously covered developments in theater for the "Dramatists Guild Quarterly." Tang graduated with a Bachelor of Arts in economics and political science from Yale University and completed a Master of Professional Studies in interactive telecommunications at New York University.