Anyone who has ever been in a gym before is familiar with the gleaming banks of shiny exercise machines. Coming in all shapes and sizes, they are usually cause for the newcomer to the gym to pause and ask, "What IS all of that stuff?"

Well, according to the price that the gym paid for any one piece of that equipment, I certainly hope that it not only stimulates your muscles, but also cooks your breakfast, washes your car, and brings the kids home from soccer practice! Now the question becomes whether or not those machines were worth the price, or if you'd be better off doing a home aerobics video with a can of soup in each hand….

Personally, I would advise you to get the low-sodium version of the soup, serve it up alongside a tomato sandwich, and then go buy yourself some free weights. Yes, that is just my opinion, but it does come with some scientific reasoning behind it.

Natural movement vs. Controlled movement

One of the things that you need to remember is that when you are exercising, you are training for LIFE. You may spend an hour a day at the gym, but that still leaves 23 other hours for your muscles to function without the aid of that fancy equipment.

Whenever you do any given exercise, the movement of your body during that exercise is called the Range of Motion. The greater and more difficult the Range of Motion, the more effective the exercise is, because your body has to work harder to perform that movement.

Let's take a classic dumbbell bicep curl for our case study. If you aren't familiar with the movement, it is basically performed by standing up straight with your palms facing forward, and a pair of dumbbells held down at your sides. You concentrically contract your biceps (also known as flexing your elbow) to bring the dumbbells up to approximately shoulder level, and then repeat the movement for a prescribed number of repetitions.

Let's take that same muscle movement and do it using a bicep curl machine. You sit down, brace your upper arms on a pad, grasp 2 handles that are in front of you, and do that same fancy elbow flexing movement to move the handles in an upward motion. Pretty easy stuff so far, right?

Now let's examine the muscles that are used in this motion. Wait - I thought we were concentrically contracting the biceps? That is correct, and if you are using the bicep curl machine, that is pretty much ALL you are doing. For one, you are sitting down. You know, like you did all day at work, and then in your car on the way to the gym. Then, your upper arms are braced on a nice soft pad to keep your upper body stable while you pull the handles upwards. The machine has effectively limited the muscles used in this exercise to the biceps, as well as the muscles in your forearms and fingers as you grip the handles.

Let us now sidestep over to the weight room where the dumbbells are kept, and once again get in the start position for a standing bicep curl with the dumbbells. Notice the term "standing". You know, like you DIDN'T do all day at work, and hopefully also did not do in your car on the way to the gym. So before we even start the exercise, we are using more muscles than we did on the machine - namely the leg muscles.

Now let's pick up a 10 lb dumbbell in each hand. We've just added 20 lbs to our body weight. What is keeping us from losing our center of balance and falling clean over? The abdominal muscles and the muscles of the lower back and spine. Now we are using our legs, our abs, and our back. Flex those elbows and start to raise the dumbbells. Now our center of gravity has become a fluid state, and our legs, back, and abs all have to constantly compensate to maintain posture. Oh, and the biceps are also in on the action by this point, as are the forearms, the fingers, and the shoulder girdle.

We now have the dumbbells all the way up and it's time to start lowering them again, via an eccentric contraction of the biceps (also know as extending the elbow). What muscle group controls the extension of the elbow? The triceps on the back of the arm.

Did you lose track yet? It's okay if you did because you have illustrated the point:

Machine Bicep Curl: Uses the biceps, forearms, and fingers
Cost: Thousands of dollars

Standing Dumbbell Bicep Curl: Uses the biceps, forearms, fingers, legs, abs, back, triceps, and shoulders.
Cost: $40 for a good set of dumbbells that can be used for dozens of other exercises

In a nutshell, free weight exercises simply USE MORE MUSCLES than machines do, which make them more effective. Does that mean that the machines are a complete waste? Absolutely not! In some circumstances it is BETTER to stabilize the muscles being used in any given movement. However, those circumstances are the exception, rather than the rule.

So what do you do? Change up your routine, and incorporate free weights as well as machine exercises. However, keep the machine work to a minimum - say 20% of your total time spent working with weights. Spend the other 80% developing your stabilizer muscles, your sense of balance and coordination, and if nothing else - just standing up!

After all, you can go home and sit down on the couch to enjoy your post-workout snack. The bicep machine already brought the kids home from soccer practice, remember?

About the Author

Aaron Potts is the owner and creator of Fitness Destinations. Aaron's experience in the health and fitness industry includes one on one personal training in many different environments, maintenance of several health-related websites, and authoring of many fitness-related products for consumers and fitness professionals. http://www.fitnessdestinations.com