It’s a simple comparison of free weights against the machine weights. Free weights include anything that you have to pick up and hold, acting against gravity. Machine weights are already in position for you to use in the set range of motion. There will obviously be pros and cons to both sides, but we aim to find out which will work better for builder solid muscle mass. Cables are a type of combination of both, so we will leave them out for the purposes of this comparison.
Firstly, free weights work more muscles at one time, then machine weights do. For instance, during bench press, you will be engaging your core as well as your biceps and triceps for balance and of course, your chest. In a machine situation, it will be a set push in a set range of motion only using your chest muscles. You will find that you are often working and engaging those smaller muscles where the balance is key, and therefore your overall strength increases.
Sometimes you want to isolate a certain body part such as quads or the “teardrop”, and that is when the leg extension machine can be perfect for engaging only the muscle you want to use. I find myself using mostly free weights, but I do use machines certain times when I need that isolation or when I have had an injury before, and I need to keep the range of motion clean.
Furthermore, it all depends on where you are at with your training. If you are still a beginner or not looking to bulk up massively and compete on stage, machine weights can be absolutely perfect and also your risk of injury is very minimal. Your heavier and more serious lifters will more often head towards the free weights, which can also be intimidating to the average person. Sometimes I even get tired of all the big dogs taking up the free weights area, so I opt to use certain machines.
Overall, both have massive advantages, but the free weights will work more muscle groups and increase lean muscle. So the free weights win the battle of the weights, but that does not mean that machines do not work as effectively. Both have massive pros and cons.