Smith Machine or Free Weights?

A common question I get asked is this: "Nate, which is better - free weights or machines?" In fact, if I was given a nickel for every time I've heard this phrase, I'd be writing this blog from somewhere in the Caribbean. The fact is, both machines and free weights have a wide variance of advantages and disadvantages based on the clients specific needs.

In this study, they compared bench pressing using two different modes: Smith Machine and Barbell. Using EMG (measurement of the electrical activity delivered to the activating muscle) they determined that activation of the pec major and anterior deltoid were about the same. The difference was with the middle deltoid - which was HIGHLY more active during the Barbell bench press than with the Smith Machine.

This increase in activation was linear to the increase of resistance. In other words, the heavier the weight, the more the muscle had to work. (Simple, yet so elegant.)

Reasons for the increased activation of the middle deltoid, they concluded, was that this global mover would actually fire as a GH (glenohumeral) stabilizer. Fascinating! What I would like to know is how the lower trapezius, pec minor and SITS muscles respond. Assuming there is less activation of the deep core muscles during the Smith Machine bench press, does that have an influence on the reduced activation of the middle deltoid? Increased activation of the SITS muscles? Interesting...

Overall, their final conclusion was supporting the Barbell bench press for improved upper body strength development - and I would agree. One of the greatest benefits of exercise is creating the path of motion yourself. This leads to improved kinesthetic sense, increased calorie expenditure & fiber recruitment and overall movement quality (granted the structural integrity of the kinetic chain is sound).

So dust off those benches and don't be afraid to move a little iron around!