Bench Press Grip Widths & Muscles Worked! Varying your bench press grip width shifts the focus on different muscle groups. The main muscles involved are the chest, shoulders (specifically the anterior deltoids), and triceps. A narrow grip emphasizes the triceps, but as your grip widens, triceps involvement decreases while chest and shoulder activation increases. A wide grip can actually helps you bench a bit more weight, but it comes with drawbacks—it reduces your range of motion and increases t