PT on the Net Research

Smith Machine - Proper Use?


The club where I work just got a new piece of equipment called a Smith machine. Most of the members don't know what they're doing. Do you have any information on the proper way to work the Smith machine? I've never cared for it myself as it's too hard on the knees if not properly instructed. I had a member ask why it's easier to lift more weight on an incline chest press with the Smith machine than it is on a flat bed Smith machine chest press. This same man refers to himself as having a greyhound stature. He is about 49 years old, lean and mean. He wants to know why he can work the hell out of his legs and not get sore on the Smith machine, but when he works his upper body, he feels it.


The Smith machine is a bar mounted on two tracks allowing for only a directly vertical motion. The two tracks essentially equate to multiple added force vectors, decreasing the weight of the mounted bar. When positioning the body, it is crucial to take into account that the natural ARCING path of motion of the resistance seen in squats, presses and pulls CANNOT occur with the use of this machine. This can create abnormal stress to the working joints, which is a possible problem.

As far as your member's question, I can't possibly answer either of them without witnessing his mechanics and knowing subjectively what he means by "working the hell out of his legs." It is peculiar that he gauges the productivity of his workouts by how "sore" he gets as this is not healthy system of measurement.

Pleas keep in mind the following (taken from "The Science of Loading" by Mitch Simon, MS):

"If given adequate rest and nutritional support, our bodies tend to respond to the stress of working out by overshooting the pre-workout levels of metabolic substrates, biochemical cofactors, contractile proteins, and other elements specific to the type of exercise performed, in a process known as super compensation. The new levels aren't permanent and will return to pre-workout levels if we don't exercise again in timely fashion (with in a few days). If a client-athlete experiences DOMS (delayed onset muscle soreness), following a workout, it is by no means an indication of a good workout. In fact, if the soreness is enough to interfere with the workout we have a paradox: If our soreness is serious enough to cause us to miss a workout, we will lose our super compensation; if our soreness is serious enough to interfere with a workout and we workout anyway, we risk injury and overtraining. Stretching to reduce DOMS has been shown to be ineffective and may even prolong soreness. Only two things reduce DOMS:

  1. Anti-inflammatory and pain killing drugs.
  2. Performing the movements that caused the soreness at greatly reduced intensity.

Take home message: Don't train people in such a way that they become very sore. It's useless and self defeating.