|The dumbbell bench press is a pec stretcher. Doesn't it already look like maximal pectoralis major activity?|
The true purpose of this study by scientists from Brazil and the US was to investigate muscle activation, total repetitions, and training volume for three bench press exercise modes, the smith machine (SMBP), barbell (BBP), and dumbbell (DBP) - all followed by a triceps extension (TE).
With nineteen trained men as subjects, the scientists had each study participant perform three testing protocols with 4 sets of bench presses (10RM) with dumbbells, barbells or smith machine being the primary exercises that were then followed up with triceps extensions and two minutes of rest.
|Figure 1: EMG activity in pectoralis (left) and the anterior deltoids (right | de Araújo Farias. 2016).|
|Figure 2: Bench press repetition performance and volume for each mode (de Araújo Farias. 2016).|
|Figure 3: Mean and standard deviation values for IEMG (a) bench press (pectoralis major activation) and (b) bench press (triceps brachii activation) with and without pre-exhaustion in Suares. 2016).|
As previously pointed out, though, there is no way of using these results for reliable prediction about the long-term adaptational response to training with dumbbell, barbell and smith machine. If we go by the prognostic power of training volume, it should be the dumbbell with a total volume of 31.2 ± 3.2 reps (versus the BBP 27.8 ± 4.8) that builds the most muscle. In that, I will leave it up to you to decide whether it's a coincidence that the dumbbell bench press also produced the greatest EMG activity ... ;-)
What I can and still want to tell you, though is that using dumbbells had the added benefit of showing the least interference with the subsequent triceps extensions (total volume: BBP = 1204.4 ± 249.4 kg; DBP = 1216.8 ± 287.5kg SMBP = 1097.5 ± 193 kg) - an observation that appears logical, and still raises the question: what's more conducive for your gains? The pre-exhaustion of the triceps you get from barbell bench presses and the resulting increase in EMG activity, or the rest your triceps will get during dumbbell bench presses and the subsequently increased training volume during triceps extensions. Well, I can't tell, but based on previous studies, it would appear as if the increased activity and decreased volume would balance each other out and explain why previous research found conflicting results (Prestes. 2015).
- Brennecke, Allan, et al. "Neuromuscular activity during bench press exercise performed with and without the pre exhaustion method." The Journal of Strength & Conditioning Research 23.7 (2009): 1933-1940.
- de Araújo Farias, D., et al. "Maximal strength performance and muscle activation for the bench press and triceps extension exercises adopting dumbbell, barbell and machine modalities over multiple sets." Journal of strength and conditioning research (2016).
- Prestes, Jonato, et al. "Discussion of “The effects of pre-exhaustion, exercise order, and rest intervals in a full-body resistance training intervention”− Pre-exhaustion exercise and neuromuscular adaptations: an inefficient method?." Applied Physiology, Nutrition, and Metabolism 40.8 (2015): 850-851.
- Soares, Enrico Gori, et al. "Comparison between Pre-Exhaustion and Traditional Exercise Order on Muscle Activation and Performance in Trained Men." Journal of sports science & medicine 15.1 (2016): 111.