The most common argument for the use of machines is that they’re safer. There is nothing safe about a fixed range of motion. Most machines jam people’s joints into awkward positions, making them less safe than with free weights. Because free weights necessitate that you use your muscles to control the weight and range of motion, you actually activate more muscles and burn more calories using free weights than machines, making it a more effective muscle-building, strength-enhancing and fat-burning solution. Machines are also less “functional,” since they don’t allow you to use your core to stabilise your midsection while going through the range of motion, as you would in every real-life movement.
Free weights also give you more of a variety in exercise choices and allow you to integrate core strengthening with typical lifting movements.