Do you prefer free weights or machines? Why?
I used to always use machines until I went to college. The trainers at the University of Richmond had us use all free weights. Now I use a combination of both depending on what I'm doing.
See what Active Expert Joe Decker, "The World's Fittest Man", has to say in this article:[Strength Training: Free Weights or Machines?|http://www.active.com/fitness/Articles/Strength_Training__Free_Weights_or_Machines_.htm]
Currently I am doing both. I use machines when I am with my PT, because of recovering from carpul & elbow surgery ( 3 months ago) and using 5# dumbbells at home.
Both are good.
Like Active Expert Joe Decker said, "...consistency, intensity, and variation...". I also agree that single leg extensions and curls are great macchine exercises. The peck deck is also cool because the hands can be brought all the way together for that extra degree of contraction. This can also be accomplished with a cable cross. The dual cable cross is an awesome macchine because it can accomidate almost any movement. One macchine that I don't like is the "Smith Macchine", which is a cage that has a barbell built into it, and can latch in at different heights. It makes a great stretching rack, but as a weight training tool, I do not like the limited range of motion. I see people all the time performing squats with it, and their feet are positioned way out infront of the bar, and their posture just bothers me. If you can't back squat that much weight with a barbell, then don't. Do a leg press or something. For calf raises, I prefer to have someone jump on my back or wear an X-Vest, because of the way that the weight is distributed, plus it reminds me of Arnold training for Mr. Universe.
This question reminds me of the book The Naked Warrior by Pavel Tsatsouline. One thing he suggests is no shoes, no mirrors and no gloves. It is the no mirrors concept that I feel has revelance to this question. He said that Russian power lifting champions often train blindfolded to help with kinesthetic awareness. Since macchines limit the range of motion, yes they help beginners develop strength, but training free weights can help to understand where your body is in space. And a word of caution, just because you're using a macchine doesn't mean that your form is proper or safe. Retract them scapulas! Sit up straight. And don't forget to breathe.