How does bench angle affect upper body muscle activation during bench press exercise?

The authors' outcomes support the use of a horizontal bench press to attain activation of the upper and lower pectoralis major during the lift. However, interestingly it was found a bench incline of 30° or 45° resulted in increased muscle activation providing a useful insight into effective adaptations of bench press exercise for optimal strength and musculature. They conclude that "the present investigation demonstrate(s) the importance of considering the effects of muscle activation throughout different time points of the contraction/lift as variations may be evident…in an effort to optimise a resistance-training programme with the goal of improving muscle strength and development of the pectoralis major, it would be beneficial to include horizontal bench press and an incline bench of 30°."

For the study, 14 resistance trained participants undertook 2 training sessions; in the first session, participants were asked to complete 1 repetition maximum (RM). This was defined as one repetition of a horizontal barbell bench press with the greatest amount of weight. On the second session, fitted with electrodes to assess muscular activation, participants completed 6 repetitions for each of the 4 barbell press angles at a resistance equivalent to 65% of the previous weight. Effects of bench condition were observed on the duration of muscle contraction and the contraction phase of the upper and lower pectoralis major, anterior deltoid and lateral triceps brachii.