I always here people say things like, “why are you doing free weights, you’re not going to get big from that!” Here I am going to examine the validity of this statement.
Free weights definitely have their advantages. They require more stabilizer muscles than machines because you have to balance the weight as you lift. This, in turn, uses the most amount of muscle mass to perform a particular lift.
Machines do not need to recruit stabilizer muscles to perform the lift because the machine is on a fixed path. This mean that the shoulders and delts that were being used during a flat bench press will not be used nearly as much during a machine press.
However, machines allow you then to focus more on the targeted muscle while not having to worry about the stabilization muscles that might be a weak point for you. Also, if you lift with just as much intensity as with free weights, then machines will get the targeted muscles just as strong.
Bottom line: Do not neglect free weights, as this will slowly weaken some of the stabilizer muscles over time and might make you “peak” and stop growing because of those weak spots. Although, it would not be a bad idea to start out your work out with free weights and then later on, when your stabilizer muscles are fatigued, to switch to some free weights so that you can