The purpose of the study was to compare the muscle activity in the prime movers and antagonist between the barbell bench press (BBP) and the dumbbell flyes (DF) Seventeen resistance-trained men (age 22.9 ± 1.8 yrs; height 1.80 ± 0.06 m; body mass 80.0 ± 8.3 kg), with 4.8 ± 2.0 years resistance training experience, completed the study. The surface electromyographic activation was measured in four different muscles (pectoralis major, anterior deltoids, triceps brachii, and biceps brachii) during six repetition maximum loads in both exercises. To better understand eventual differences, an in-depth analysis of the fifth repetition was performed, dividing it into six phases (lower, middle, and upper phase of the descending and ascending movement). The results showed a higher muscle activation in the whole movement and the majority of the lifting phases for pectoralis major, deltoids anterior, and triceps brachii for the BBP compared to the DF (8-81 %, p ≤ 0.05). However, the antagonist biceps brachii showed a higher muscle activation (57-86 %, p ≤ 0.05) in the DF compared to the BBP. In conclusion, both exercises could be included in training programs, but the BBP should be emphasized because of the higher muscle activation overall. Among specific populations, were tasks based on strength and control in a horizontal shoulder flexion position with extended elbows often occurs, the DF might prove useful.

• The findings of the present study demonstrated that performing the BBP activates the agonists and synergists, to a greater extent than the DF. The DF, on the other hand, activated the arm flexors (biceps brachii) to a greater extent than the barbell bench press.

• Lower external loads were lifted with the DF than the BBP. Therefore, the authors recommend the BBP for athletes or others engaged in resistance training.

• For variation, both exercises should probably be included in the program but with an emphasis on majority of the volume focused on the BBP due to the higher muscle activation overall.

• The DF could prove quite useful among specific populations and tasks where strength, stabilization, and control in a horizontal shoulder flexion position with extended elbows is desirable.