The Smith machine — and its disadvantages

For years, Smith machines have littered the floor of commercial gyms. If you are unfamiliar with this piece of equipment or have never used one, it is simply a fixed barbell with steel rails and adjustable pegs or latches that promote strict vertical motion. People will often use it for squatting and or bench-pressing without a spotter because it allows one to rack the weight if they can no longer handle the load.

Although the ability to bail on a heavy lift at the turn of wrist may be appealing, the machine presents its own disadvantages. Furthermore, users do themselves a disservice by the stimulus (or lack thereof) that they receive compared to similar free weight exercises.

Is it unsafe?

I never understood why people gravitated toward using Smith machines until one day when I was an intern in college and our head strength and conditioning threw his towel over one, proclaiming it to be the best towel rack he’s ever seen.

All jokes aside, it may come as a surprise to some, but the human body does not do well when in fixed positions, particularly under load. Ask anybody who has ever had bindings fail to release in a ski boot and subsequently suffer a tibia-fibula fracture. When major forces are applied to the body without the ability properly absorb/disperse them elsewhere, bad things happen.

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In order to understand how this applies to strength training, take a look at the barbell bench press: Contrary to popular belief, the bar does not travel in a completely linear path throughout the motion. It moves in a diagonal path, as can be seen in the picture.

The reason for this is because in order for the bar to be brought safely to the midline of the chest, the shoulder blades must be retracted, ultimately forcing the elbows slightly inward. When using a Smith machine, this is simply not possible due to the bar being fixed, causing a great deal of stress on the shoulders. While the trauma induced from a Smith machine bench press might not prove to be as severe as the aforementioned tibia-fibula fracture, repetitive use of this movement over time can cause some issues.

The bench press is only one of example of the poor biomechanics promoted during strength training with a Smith machine. Squatting presents its own issues, mainly as the result of the movement requiring a vertical shin and angling of the feet forward to a degree that the movement resembles more of a wall sit than a squat. While this may be difficult to picture for some, understand that from a performance and movement standpoint, it is far from optimal.

What about the results?

Besides the fact that one may be running an increased risk for injury with the smith machine, it appears to be less effective in performance outcomes than traditional free weight training, specifically muscle activation. A 2010 study in the Journal of Strength and Conditioning Research compared EMG-analyzed muscle activation between Smith machine and free weight bench press, finding that specific muscle group activations were significantly greater in the free weights groups. That should come as no surprise to anybody who has ever used fixed machines for strength training versus a free weight. A fixed machine removes the need for one to stabilize and keep the weight moving in appropriate path which ultimately recruits not only site-specific musculature to a greater degree but the surrounding structures as well.

Along with the disadvantages of squatting and or bench pressing in a Smith machine, the other major issue it presents is that it limits the exercises that can be executed as well as the planes of motion trained. There can be no Olympic lifting done (please don’t try) for obvious reasons and nearly no exercises done in the frontal plane. While I understand some individuals may find great success with the smith machine and every piece of equipment has a time and place, I encourage those of you who may currently use it to take a step back and critically analyze if it the best choice for your program. A number of exercises, movements and pieces of equipment can fill a spot in a program, but you must always ask yourself two questions: 1) Why am I choosing to include this? 2) Is this the best choice for me, or can I select something better?

Jimmy Pritchard has a bachelor’s in exercise science from Colorado Mesa University and is a certified strength and conditioning specialist through the National Strength and Conditioning Association. He is the director of strength and conditioning at Ski & Snowboard Club Vail. Contact him at 970-331-3513 or jpritchard@skiclubvail.org. Check out his website http://www.pritchardperformance.com.