The bench press is foundational to resistance training programs. Not only is the exercise regularly prescribed by strength coaches and personal trainers, but it is also included in fitness test batteries, and it is one of three lifts performed in competitive powerlifting.

The bench press can be performed in various ways, including with different grip widths. A medium or standard grip involves holding the bar slightly wider than shoulder-width apart. A narrow grip involves holding the bar with the hands closer together near the centre of the bar. A wide grip involves holding the bar about as far wide as possible.

A recent study examined if grip width during the bench press impacts the extent to which certain muscles are active during the exercise. Such studies are important because they help us to understand which muscles are most likely to increase their strength if a particular grip is used during a bench press training program that lasts several weeks.

In the study, a group of 28 men performed bench press repetitions with a narrow grip (armpit-to-armpit width), medium grip, and wide grip (81 cm apart). Electromyography was used to measure muscle activity of chest, shoulder, and arm muscles while participants performed the exercise. The muscles measured included the pectoralis major, deltoid, biceps, triceps, and latissimus dorsi. The amount of weight participants lifted during testing was that which they could lift exactly six times (i.e., the 6 repetition maximum or 6RM). 

The researchers found that the pectoralis major, anterior deltoid, and triceps brachii were the muscles most active during the bench press. However, grip width impacted the extent to which the muscles contributed to the movement. For example, the triceps was more active when narrow and medium grips were used, whereas the anterior deltoid was more active with wide and medium grips. For the pectoralis major, grip width had little impact on its level of activity.

Also, the researchers observed that grip width impacted how much weight the participants could lift. With a narrow grip, the participants lifted 8.4% less weight than with a medium grip and 6.6% less weight than with a wide grip. A previous study also found that force output during the bench press is greatest when a medium grip is used. 

Overall, the findings from the new study indicate that grip width during the bench press impacts muscle activity and how much weight can be lifted. So, if your goal is to lift more weight during the bench press and have the greatest collective muscle activation, a medium grip is recommended. If your goal is to activate more triceps, a more narrow grip is recommended. If your goal is to activate more anterior deltoid, a medium or wide grip is recommended.

Nevertheless, the bench press with any grip width will result in high levels of muscle activity of the pectoralis major, anterior deltoid, and triceps. Consequently, the bench press will cause improvements in the strength of these muscles. This is why the bench press continues to be a foundational exercise for most upper-body strength training programs.