Exactly, I use free weights and machines all the time....its the folks that abandon the free weights completely in favor of the machines that lose out.
You could reach your max potential ONLY USING MACHINES as they certainly are better designed to get the job done much more efficiently.Free weights are overrated actually.
I always find this argument funny... machines versus free weights - like a single muscle fibre can tell the difference - it only knows whether it is been made to contract or not that is it.Also, I'd like to see someone train calves or hamstrings exclusively without machines too...
Anything that exhausts the muscle and is difficult will work.IF I were to put you in an Artifical enviroment of higher gravity, lets say 4 times the amount on earth, but one that is survivable.You will in fact have better musculature from just existing and interacting in that enviroment than you would with all of your free-weight training.You MENTALLY think free weights are better. It is more of a psychological issue than anything.
You could even have the BEST quads, by just doing leg extensions and nothing else.
i dont use any machines for calves just stack the wieght on my lap for seated and do standing calve raises off a block......... and for hams stiff leg deads after quads..