A comparison of muscle activation between a Smith machine and free weight bench press.
Schick EE, et al. J Strength Cond Res. 2010 Jan 21.
Within bodybuilding circles there is some disagreement on whether the barbell bench press or the same exercise performed on a smith machine is superior. Proponents of the bench press cite the fact that it requires the trainee to stabilise the weight being lifted in space which requires a greater effort from the body than the smith machine. By contrast, those advocating the use of the smith machine point out that by not requiring the athlete to stabilise the weight the smith machine allows for greater overload on the muscles of the chest.
Methods: This study compared muscle activation rates between the bench press and the smith machine to attempt to answer the question as to which is superior. Participants were classified as either experienced or inexperienced and required to perform test sessions on both exercises at 70% and 90% of their 1 rep maximum (1RM). EMG testing compared muscle activity during the concentric phases of both exercises which were trained in separate sessions. In each session the participants’ 1RM was established. Subsequent to this, they performed 2 reps at 70% of 1RM and 2 reps at 90% of 1RM.
Results: Results indicated greater activation of the medial deltoids on the free weight bench press than the smith machine version. In addition, there was greater muscle activation at the 90% of 1RM load than the 70% load.
Our Take: At Predator we would generally always argue in favour of free weight exercises in preference to machine exercises which, as this study shows, leads to lower muscle activation rates particularly of stabiliser muscles like the medial deltoids. In addition, one thing this study could. It address is the fact that with long term use, smith machine exercises will force the body to move along a fixed plane of motion which is alien to how the human body should move. Even supposedly straight movements like the bench press occur by the bar path deviating around an axis. Similarly, when people walk forward in a straight line the movements of the joints such as hips will not go forward in a fixed path. By forcing the body to move in an unnatural pattern the usage of the smith machine is not recommended due to its ability to disrupt normal joint movement, and correct neuromuscular firing patterns. In laymans’s terms, long term smith machine use cannot only make muscle growth more difficult but can produce an increased likelihood for injury and diminution in sporting performance (which do not occur in a fixed plane).
© 2012, Reggie Johal. All rights reserved.