Why cables aren't machines

Here and elsewhere, you'll find a bias against machine-based training.

"Don't 'do the machines.'" and "free weights are superior to machines."

But a frequent if not almost universal exception is made for cable machines and cable exercises - pulldowns, seated rows, pull-throughs, belt squats, and so on - all of which require a cable system to do.

Even a basic knowledge of scientific simple machines will tell you that these are machine exercises. They require a pulley, one of the Six Simple Machines you may remember from school.

The reason is that simple pulley only allows you to change the direction of force. You can rig a stack of weights hanging from a cable, allowing you to pull horizontally (like in a seated row) but raise the weights vertically against gravity. You can rig them to allow you to pull vertically (like in a belt squat or cable curl) but raise the weights vertically.

What these cable units don't do - at least, the good ones don't do - is force you into a limited range of motion (ROM). They don't provide an array of pulleys designed to lower the amount of force you need to move a weight. It's simply providing you with a way to move weight without needing to contrive a position that lets you pull the weight against gravity. Not every machine with a cable on it is like this, though - only those that don't restrict your ROM count.

That's why cable machines aren't machines. They are simple machines, but they don't help you lift the weight...they just let you lift it in different ways than a barbell or dumbbell can.