Train with free weights to increase your bench press and gain upper body strength. Research shows that instead of relying on the Smith machine, barbell and dumbbell chest presses should make up the core of your training to increase strength and size in the chest.
A new study in the Journal of Strength and Conditioning Research compared muscle activity and 1RMs in three different chest press exercises: A Smith machine chest press, a barbell bench press, and a dumbbell chest press. Researchers wanted to see if increasing the degree of freedom of the exercise would affect muscle activity, the 1RM, or the amount of time spent in the sticking region of the lift.
The Smith machine press is a 1 degree of freedom exercise because the barbell can only be moved vertically, whereas a free-weight barbell allows the barbell to be moved horizontally as well. With dumbbells, there is much greater freedom that must be controlled at the shoulder joint. It’s reasonable to suggest the greatest load could be lifted with the Smith due to the need to only control 1 degree of freedom, but that was not the case.
The barbell bench press allowed trained participants to lift the greatest average load (106.4 kg), followed closely by the 1RM achieved in the Smith chest press (103.6 kg), and the dumbbell press coming in far behind (89.5 kg). It’s possible participants did better in the barbell bench press because that was the lift they commonly trained. The unnatural path of the Smith machine is another possible reason for the barbell trial achieving heavier maximal loads.
Electromyographical (EMG) readings of muscle activity showed that the pectoralis, deltoid, and biceps were all activated to a greater degree with the two free weight trials than the Smith machine, which is likely due to the limited degree of freedom of the Smith exercise. The horizontal displacement of the free weight chess presses causes more pec and deltoid activity to control and lift the bar.
EMG readings also showed that biceps activity was higher and the triceps were less active due to the need to limit lateral movement of the dumbbells during the concentric motion through the sticking region of the press.
Take away the understanding that both barbell and dumbbell chest presses can be programmed into some form of a periodized training program to get the best results. Free weight exercises are always preferable to using the Smith, and for the chest press, the Smith should be completely avoided. The unnatural path of the bar will place too much stress on the joints and it causes reduced muscle activation—and possibly a lower 1RM. In addition. Plus, recent research shows doing a bench throw performed for power on a Smith machine leads to lower peak force, power, and velocity. Avoid it!
For more on how to mix up your chest workouts for maximal gains, read Top Ten Bench Press Variations.
Ven Den Tilliaar, R., et al. The Sticking Region in Three Chest-Press Exercises with Increasing Degrees of Freedom. Journal of Strength and Conditioning Research. 2012. 26(11), 2962-2969.