Smith Machine Vs. Free Weights

Popular for strength training, the Smith machine allows you to do barbell work but with the stability of a selectorized machine. As opposed to a free-standing Olympic bar, the Smith machine glides along a set plane of motion. When incorporating the Smith machine into your workouts, recognize the advantages, and disadvantages, it has when compared to free weights.

Features

A large, hulking contraption, the Smith machine consists of an Olympic bar that slides along a vertical track. The bar is plate-loaded and locks into either side of the track. The stopping point for the bar may be set anywhere along the vertical track, and the user only needs to rotate the bar to unlock it and allow it to move along the track.

Significance

Many weightlifters use the Smith machine to perform squats, lunges and bench presses. Questions exist about the biomechanical benefit of using the Smith machine as opposed to free weights. Because you are guided along a track, it may not allow for a natural execution of movement. During some exercises, lifters find it possible to hoist a greater amount of weight when using the Smith machine. It is important to understand if the ability to lift more weight with the Smith machine is actually helping you build muscle, or if it is simply a function of the machine's support and cheating your gains in the long run.

Benefits

The Smith machine mimics movement that would be conducted when doing similar exercises with free weights, but it provides a safe alternative because of the guiding aspect of the vertical bar. The Smith machine offers protection for solo trainers who do not have a spotter to save them during a lift that becomes too heavy. The Smith machine also offers great benefit for tired muscles that have already conducted some free weight exercises, and it provides for greater isolation of the pectorals during a chest press and the hamstrings during squats.

Drawbacks

The primary disadvantage in using the Smith machine is that it does not tap into the stabilizing muscles as well as exercises performed with free weights. As a result, the Smith machine fails to improve a user's balance and functional ability to react to unstable conditions. Furthermore, it can give you a false sense of strength, so that if and when you do go to free weights, you may try to lift more weight than is appropriate.
A study in the "Journal of Strength Conditioning Research" published in December 2009 compared the free-weight squat with the Smith machine squat in six healthy individuals. In this case, researchers used electromyography to measure muscle activation and found the free-weight squat activated muscles at an average rate of 43 percent more than those performed on the Smith machine.

Maximization

Despite the drawbacks, the Smith machine adds value to your training routine. Make sure you supplement any Smith machine exercises you perform with free-weight work, but adjust your workload accordingly. The Smith machine may also help with muscle development to isolate certain primary muscles, after you have addressed stabilizing muscles and primary muscles with free-weight work. The stability of the Smith machine does allow you to isolate hamstrings more than in a free-weight squat because you can stand farther forward.