Research corner time. I've had some time to sit down with the latest Journal of Strength and Conditioning and peruse the latest topics. Everyone's favorite, the good 'ol bench press got a few studies this time around, and one of them caught my eye as it is applicable to many gym goers:
"Comparison of Muscle Activation Between a Smith Machine and Free Weight Bench Press"
Done at the Exercise Physiology Lab at Cal State Fullerton, this study looks at how hard certain muscles work during a bench press done in a Smith machine
and free weight bench press with a barbell:
Back to the study. They used EMG sensors attached to the deltoids, triceps, and pec major to measure how hard the muscles has to work to accomplish the task. Long story short the free weight movement elicited greater muscle activation than the machine version.
And as you can tell the dude above is way more jacked than the woman in the Smith machine.... ;)
But another important point is that the free weight exercise requires greater stabilization of the glenohumeral joint (shoulder) - which means that the muscles such as the medial deltoid that do the stabilization will get better at this task, which will help keep you healthy.
In other words, stay off the damn machines if you want to get stronger and have healthy joints.
And briefly, another study looked at the effect of stretching before pressing, and found that contrary to some beliefs, stretching had no effect on strength and power production.
Seeing as most guys have shoulders tighter than steel cable go ahead and get all the flexibility work in you can. Yeah yeah...if you are a powerlifter than you will want to refrain from a lot of stretching 2 minutes before you lift... otherwise keep working on shoulder mobility as it will pay off big time down the road.