Free Weights vs. Machines: The Debate. The debate on whether machines or free weights are better for building muscle has been around for decades. ... Then, people realized that while machines are good for training size and strength they neglect key core & stabilization muscles. Generally speaking, one is not “better” than the other in all instances. There are benefits and drawbacks to both machines and free weights, and some exercises tend to be more effective when done using one or the other. The primary difference between free weights and machines, however, is the fact that when using free weights, you can move in three dimensions: forward, backward, horizontally, and vertically. This is important, because this is how your body normally moves in daily life.
When you use free weights, you therefore end up engaging more muscles, as you have to work to stabilize the weight while lifting it. The drawback is that you’re at an increased risk of injury unless you maintain proper form.
Machines, on the other hand, are fixed to an axis that will only allow you to move in one or two planes. If used exclusively, this could lead to a lack of functional fitness, which can translate into injuries outside the gym.
