Bench Press with Free Weights or Smith Machine?

A recent study in The Journal of Strength & Conditioning Research compared muscle activation between a Smith machine and free weight bench press.
The study used 14 experienced lifters and 12 inexperienced lifters and all were male around age 20. Muscle activation was tested using elecromyography (EMG) at 70% 1 rep max (RM) and 90% 1 RM.

Not surprising the 90% 1RM elicited greater muscle activation than did the 70% 1RM and this was true for either free weight bench press or Smith machine. This has been found in many other studies and this is a reminder that to get stronger, you have to lift heavy.

What I thought was interesting about this study was that using free weights did NOT far surpass using the Smith machine when it came to engaging the pectoralis major, your large chest muscle. Also, it didn't matter if the lifter was experienced or not, the activation was roughly the same in both free weights and Smith machine.

This study did conclude that free weights lead to greater activation of the medial deltoid (you know, that tear drop shaped muscle at the top of your arm). This alone is good enough reason to stick with the free weights!

For those of you who don't care about making the tear drop shaped medial deltoid "pop" then maybe you care to know that this greater activation is because it is helping to stabilize the shoulder joint.

So, if you play basketball, baseball, tennis, racquetball, hockey or volleyball then stick with the free weight bench press. If, however, you are a novice lifter or a physical rehab patient, then start with the Smith machine for the stability it provides.

Good luck.
In good health,

Marie