The underhand bench press, also called the reverse grip bench press, works the same three major muscles as a standard bench press: the chest, the front of the shoulders, and the triceps. The key difference is where the emphasis shifts. Flipping your palms to face you changes the angle of your upper arm relative to your torso, which increases activation of the upper chest (the clavicular portion of the pectoralis major) and brings the biceps into the movement as a stabilizer in a way that a standard overhand grip does not.
Upper Chest Is the Main Beneficiary
Your chest muscle has three distinct sections: upper, middle, and lower. A standard flat bench press with an overhand grip tends to load the middle and lower portions the hardest. The underhand grip rotates your upper arms outward, which shifts the line of pull so that the upper chest fibers do proportionally more work. This is similar to the effect of inclining the bench to about 30 degrees, which EMG studies have shown produces peak activation of the upper chest compared to flat or steeper angles.
One commonly cited finding is that a narrower hand spacing increases upper chest activation during a standard bench press. Interestingly, grip width does not appear to have the same effect during the reverse grip variation. Whether you go slightly narrow or slightly wide, the upper chest recruitment stays relatively consistent, which makes the exercise more forgiving in terms of hand placement.
Triceps and Front Deltoids
The triceps remain a primary mover during the underhand bench press. They are responsible for extending the elbow as you push the bar away from your body, and that job doesn’t change with grip direction. Because the underhand grip naturally tucks your elbows closer to your sides, some lifters report feeling more triceps engagement compared to a wide-grip overhand press, where the elbows flare out and the chest takes over more of the load.
The front of the shoulder (anterior deltoid) assists the chest in flexing the shoulder joint during every pressing variation. With the reverse grip, the anterior deltoid still contributes, though the tucked elbow position tends to reduce the degree of shoulder flexion compared to an overhand press with wide, flared elbows. This can make the movement feel less shoulder-dominant for people who tend to “feel it” too much in their front delts during a regular bench.
Biceps Play a Bigger Role Than You’d Expect
One of the more surprising differences with the underhand bench press is how much more the biceps are involved. In a standard overhand bench press, the biceps do very little because the pronated (palms-away) grip puts them in a mechanically weak position for the movement. Flip the grip to supinated (palms toward you), and the biceps are suddenly positioned to help stabilize the bar and control the descent. One study comparing a free-rotating barbell grip to a locked barbell found that allowing the hands to rotate into a more supinated position increased biceps activity by 173%. While that study used a specialized barbell rather than a strict reverse grip setup, it illustrates how powerfully hand position influences biceps recruitment during pressing.
This doesn’t mean the underhand bench press replaces curls. The biceps are stabilizers here, not prime movers. But the extra demand is enough that some lifters notice biceps soreness after their first few sessions with the exercise.
How the Grip Changes Shoulder Mechanics
The underhand grip forces your elbows to tuck close to your torso rather than flaring out toward 90 degrees. This is significant for shoulder health. Wide grips with high shoulder abduction angles can reduce the subacromial space (the gap where your rotator cuff tendons pass under the bony shelf of your shoulder blade), potentially compressing those tendons and increasing injury risk over time. Research on bench press biomechanics has shown that grip widths narrower than 1.5 times shoulder width decrease both glenohumeral shear forces and rotator cuff muscle activity, which may lower the risk of instability and rotator cuff injuries.
By naturally tucking the elbows, the reverse grip mimics many of these protective effects. If you’ve experienced front-of-shoulder pain with a standard bench press, the underhand variation is worth experimenting with, though you should start light and see how your joints respond.
Proper Setup and Bar Path
Position your hands slightly wider than shoulder width on the bar with your palms facing you. Wrap your thumbs fully around the bar. This is not the place for a thumbless grip, because the supinated hand position makes the bar more prone to slipping toward your face.
Unrack the bar and lower it to a point slightly below where you’d touch on a standard bench press. Instead of aiming for your nipple line, bring the bar down to the lower chest or just below it. This accounts for the different elbow angle and keeps the movement path natural. On the way up, the bar should travel in a slight arc back toward your head, not straight up.
Expect to use less weight than your regular bench press, at least initially. The grip and altered muscle emphasis feel unfamiliar, and your stabilizer muscles need time to adapt. Starting at around 60 to 70 percent of your normal flat bench weight is a reasonable entry point.
Managing Wrist Discomfort
The most common complaint with the underhand bench press is wrist strain. Supinating your hands under a loaded barbell puts your wrists in an extended position that can feel awkward, especially if your forearm and grip strength are underdeveloped. The key is keeping your wrists as straight and neutral as possible throughout the movement. If your wrists bend backward under the load, you’re asking the small ligaments in the joint to bear force they aren’t designed for.
A few practical fixes help. First, make sure the bar sits low in your palm, close to the heel of your hand, rather than up near your fingers. This stacks the weight more directly over the wrist joint. Second, wrist wraps provide compression and external support that can reduce discomfort significantly, especially as you work up in weight. Third, if a barbell consistently bothers your wrists, try the movement with dumbbells instead. Dumbbells allow your wrists to rotate freely into whatever angle feels most natural, which often eliminates the issue entirely.
Where It Fits in a Training Program
The underhand bench press works best as a supplemental chest exercise rather than your primary heavy press. Because the grip demands more wrist stability and you’ll handle less weight overall, it’s well suited for moderate rep ranges of 8 to 12 after you’ve already done your heavier flat or incline pressing. Think of it as a tool for targeting the upper chest from a different angle, adding variety to a chest routine that might otherwise rely entirely on incline work for upper pec development.
If your upper chest is a lagging area, pairing the underhand bench press with a 30-degree incline press covers the upper pec fibers from two distinct angles and grip positions. For lifters dealing with shoulder sensitivity, it can also serve as a flat pressing alternative that keeps the shoulders in a friendlier position while still loading the chest and triceps effectively.