Here we are. This is probably the most controversial topics when it comes to recreational gym equipment. The smith machine has been both shunned and preached by various lifters and is probably the most controversial piece of equipment to ever exist in a gym (the leg press coming in a close second). You have one group of people who swear that the smith machine allows for the best muscle targeting and weight loading while lifting safely, and you have another group who swear that the smith machine is just for p*****s (and another side who honestly does not care). Recently I was asked my thoughts on the smith machine and whether I believed it to be a useful training piece of equipment. Since I have a pretty neutral stance on the smith machine, I wanted to explain to you all the pros and cons to using a smith machine and then my final thoughts on whether or not people should use it.
There can't be any pros to the smith machine, right? Wrong! The smith machine does have a few benefits. Whether you like it or hate it, the smith machine can be helpul with:
When using the smith machine, since the bar is in a fixed range of motion like other machine, you are able to target muscles in a "more isolated" manner. During a bench press, you have to focus just as much energy balancing the barbell as you do actually pressing it. WIth the smith machine, you get to focus all your energy on moving the bar through a full range of motion. That means more emphasis on the primary movers, and less emphasis on secondary stabilizers.
For those who may be injured (or prone to injury), using a smith machine can be very beneficial. When you have a low back injury, you must put less stress on the lower back, resulting in you needing to keep your torso upright when you perform lower body movements. Barbell back-squats require minimal, but still some torso lean. Front-squats require an upright torso, but also places the lower back in an intense isometric muscle contraction (still taxing the lower back) which may result in pain just like barbell back-squatting. During a smith machine back-squat (or front-squat) the torso can stay fully upright, there is hardly any stress on the lower back, and you are able to move the lower body muscles through full range of motion. The same application could be used for the bench press and a shoulder injury.
When you take out the limitations of a free weight movement (limited by your stabilizers), you are able to surpass the loads you use for free weight movements. That means you are able to progressively overload the muscles more than if you were to use a free weighted movement. With more weight, more tension, and more work done, this results in.....more muscle!!!
Just like anything else, there will always be bad that follows the good. The smith machine is amazing for muscle targeting, rehabilitation, and overload, but is the smith machine worth your time? The smith machine can be seen as a worthless piece of eqipment because:
When a movement in fixed motion, something has to move in order to compensate for the lack of adjustment. This means that you must adjust the motor pattern performed. Sometimes the movement is performed with the intentions of treating the smith machine as a regular barbell. What happens is the movement places unneccessary and even immense stress on the ligaments, tendons, and joints of the body in order to perform the movement intended. For example the smith machine bench press allows you to press in a straight line. What happens is since you cannot perform the bench press in a slight arch motion (like the bench press is supposed to be performed), your shoulders must compensate the motion by being forced out instead of down. This increases the strain on the shoulders and can result in severe rotator cuff injuries. If you allow your shoulders to go down to your side instead of out, the stress is placed on your elbows since your elbows forearms will be bent back to complete the range of motion. This results in the elbows being lower down your side than the bar, placing a great deal of stress on your elbow joint. Either route with the smith machine pressing can lead to some serious and career changing injuries.
The blessing of a smith machine can also be a curse. When you take away the stabilizers, you take away their limitations to the exercise. Also when you take away the need for stabilizers, you let them lag behind and allow them to weaken. Stabilizing muscles are what keeps your body in alignment and structural integrity. The abdominals for example, all are stimulated during free weighted movements which involve standing, bracing, and even some sitting movements. When you eliminate the need for a strong core, the abdominal muscles start to atrophy (weaken and shrink). What happens is any movement that involves using the abdominals may start to suffer and regress due to the abdominals being a limiting factor. That could mean your weak abdominals could effect your squatting, push-ups, or even just walking with your back pack on with good posture. The abdominals are called the "core" for a reason. The abdominals are the center of the body and also provide the foundation for a solid strength base. Being able to stabilize is necessary, even essential for your ability to maximize your strength and power.
The last con of the smith machine is of my own experience. The smith machine is just too d*** easy. Just like the leg press, the smith machine is a fixed weight that glides through the air while being fixed with the poles that stabilize it. One thing I really disliked about the smith machine was the momentum you could use from the bars ability to slide up the stabilizing construct. I never really realized how easy it was to use a smith machine until one day that was the only piece of equipment I could use and go heavy on (at a hotel). At a time I could only bench 315, I was sitting there doing repetitions with 345 like it was nothing! After I started the movement, I pretty much knew I could finish it. This may be good for your ego and showing off, but muscles are stimulated by tension, time under tension, and contraction types. If you have to load up 405 in order to get a decent training stimulus due to the momentum actually aiding you, I find the equipment very pointless. Why would I load up 405 to get a stimulus from the smith machine when I could stress my muscles the exact some with 315, while reducing the risk of injury and while strengthening my stabilizers?
I am not here to tell you the smith machine is an abomination to exercise equipment, nor am I here to tell you it is the next big thing. I believe the smith machine has it's place in some exercise programs, but only when it is used for specific purposes. Using the smith machine does not make you a weakling, nor does it give you the right to load up the plates in order to show off your 8 inch arms. The smith machine is like any other piece of equipment in a training facility. It has it's place and should be used only when used for a specific purpose.