Machines
vs.
Free Weights
Machines have their place, but free
weights are the way to go for the best results. I'm talking about the type of machine
where they have a different apparatus for every muscle that forces you to move according
to the limitations of the machine.
I do not consider high and low pulleys, or leg press type apparatus as machines.
For some reason, the people who make the machines (Nautilus, etc.) have it in their minds that to effectively work a muscle, you must work only that muscle, and no other one. They also say that since a lift gets easier towards the end of the movement, the weight should increase accordingly. This sounds good in theory, but doesn't really work in practice. These machines soon become limiting and frustrating to most users which is why any serious trainer uses mostly free weights, using the machines only occasionally, or as a secondary exercise.
About "isolation". If you're training for size, don't bother with too many isolation movements. Why isolate one muscle when you can work dozens of the small and supporting muscles at the same time? For most people, every muscle needs to be worked, and free weights add many the stabilizing and supporting muscles into the exercise. Take Bench press, for example, The main muscles used are the pectorals (chest muscles) but you are also working the front delts (shoulders), the triceps, the abs, and the lats (back), and the neck plus many smaller hidden muscles! Without developing these muscles, you would look incomplete (not to mention all those underdeveloped muscles just waiting to be strained, pulled or otherwise damaged). If you want size, limit the isolation exercises and focus on the compound movements. Save the isolation exercises for tweaking your physique, after you have the mass you want, or to supplement the basic exercises.
Another reason to use free weights is INTENSITY! It's almost impossible to do an intense set on a machine, the way they force you to move just doesn't allow for it, and having the weight get heavier the harder you push is just not satisfying. It's only when you do a very intense set using heavy weight and multiple muscle groups (squats, deadlifts, heavy shrugs) that you body releases growth hormone and adrenaline, which give you growth and energy respectively. You will also release "endorphins" which causes almost a high after a good set. With machines, it's very difficult to generate this level of intensity.
At the beginning, I said that machines do have their place, and that is for extreme beginners (to develop a base), recovering from an injury, as a supplementary exercise and to tweak certain muscles. If you have a pulled or strained muscle, or other injury, a machine may be safer than free weights until it recovers a bit. Anyone who starts training on machines invariably switches to free weights after a few months because they work far better, the results speak for themselves.
