What should I do with my free hand?

Let it rest at your side next to the bench, relaxed. Holding the edge of the bench makes it easier to stay balanced and is a sensible way to learn the movement, but it takes away some of the trunk work, so let go once you can stay square without it.

How much weight should I use compared with the regular dumbbell bench press?

Start with less than you hold in each hand for a two-dumbbell press. Staying level on the bench is usually the limit, so pick a load you can lower slowly on every rep without your hips or shoulders rolling.

How is it different from the Alternating Dumbbell Bench Press?

In the Alternating Dumbbell Bench Press the other hand holds a second dumbbell at arm's length, which partly balances the body, while here the free hand is empty and the trunk has to resist the twist on its own. In a study of recreationally trained young adults doing one-arm presses on a flat bench, holding only one dumbbell let them move through a larger shoulder range of motion than holding a second dumbbell up in the other hand.

Should I finish all reps on one side before switching?

Yes, that is the usual way to program it, and it keeps the trunk working for the whole set. Many trainers start with the weaker side and match its reps on the stronger side, so the gap between sides does not grow.

Can it replace the regular dumbbell bench press?

It can stand in for it in a program, but because balance limits the weight you can use, most lifters do it alongside a two-arm press like the Dumbbell Bench Press rather than instead of it.

Dumbbell Single-Arm Bench Press

What Is the Dumbbell Single-Arm Bench Press?

Dumbbell Single-Arm Bench Press is a compound exercise that primarily targets the chest and also engages the front of the shoulders, the triceps and the obliques. It is an intermediate-level movement in which you lie on a flat bench and press one dumbbell from the side of your chest to arm's length while your free arm rests at your side. Because the weight sits on one side only, your trunk has to keep you from twisting and rolling toward the working arm on every rep.

The movement trains the same horizontal press as the Dumbbell Bench Press, one side at a time. Working each arm on its own makes a strength difference between sides easy to see and stops the stronger side from covering for the weaker one. With nothing in the other hand to counterbalance the dumbbell, the obliques and the muscles around the shoulder blade work throughout the set to keep the body square on the bench. Trainers usually place it as an accessory after the main press of the day, or use it in a full-body session as a chest exercise that also challenges the trunk.

Small changes to the setup shift the work. The Dumbbell Incline Single-Arm Bench Press moves more of the load toward the upper chest and front of the shoulder, the Dumbbell Single-Arm Floor Press shortens the range because the upper arm stops at the floor, and the Kettlebell Single-Arm Bench Press puts the weight behind the wrist, so the wrist works harder to stay straight. The Alternating Dumbbell Bench Press also presses one arm at a time, but the second dumbbell held up in the other hand partly balances the body.

It suits lifters who can already press a pair of dumbbells with control and want to address a side-to-side difference or add a stability challenge to their chest work. Expect to use less weight than you hold in each hand for a two-dumbbell press, since staying balanced usually limits the set before the chest does. Newer lifters should build a base with the Push-Up and the Dumbbell Bench Press first, and the Dumbbell Single-Arm Floor Press is a steadier step in between because the floor supports the whole back and the working elbow.

Muscles Worked

MuscleActivation

Pectoralis Major: Primary
Deltoid: High
External Oblique: Medium
Triceps Brachii (Lateral Head): Medium
Triceps Brachii (Medial Head): Medium
Rectus Abdominis: Low
Serratus Anterior: Low
Triceps Brachii (Long Head): Low
Upper Trapezius: Low
Biceps Brachii: Minimal

Instructions

Sit on the end of a flat bench with one dumbbell resting on the thigh on your working side, held with an overhand grip.
Lie back, keeping the dumbbell close to your chest, and set your head, upper back and hips on the bench with your feet flat on the floor and knees bent about 90 degrees.
Hold the dumbbell beside your lower chest with the handle running across your body and your palm facing your feet, forearm vertical and elbow just below bench level, angled about 45 degrees from your torso.
Rest your free arm at your side next to the bench, relaxed rather than pushing into the bench.
Draw your shoulder blades back and down, brace your abs and keep both shoulders and both hips level on the bench.
Breathe out and press the dumbbell straight up until your arm is fully extended over your shoulder.
Breathe in and lower the dumbbell under control along the same path back to the side of your lower chest, without letting your body roll toward it.
Finish all reps on this side, then bring the dumbbell to your chest, sit up and switch hands for the other side.

Common Mistakes

Rolling toward the dumbbell
Letting the hips and shoulders twist toward the working side turns the press into a rocking motion and takes away the trunk's job of holding you square.
Pushing with the free hand
Bracing hard against the bench with the free hand does the stabilizing work the obliques are meant to do.
Going too heavy
Using the weight from a two-dumbbell press usually makes it impossible to stay level on the bench and control the lowering.
Flaring the elbow
Lowering with the upper arm out at 90 degrees to the torso puts more stress on the front of the shoulder than an elbow angle of about 45 to 60 degrees.
Cutting the range short
Stopping the dumbbell well above chest level leaves out the bottom of the press and trains less of the chest's range.
Lifting the hips
Driving the hips off the bench to finish a hard rep arches the lower back and makes the body harder to keep balanced.

Injuries

Dumbbell Single-Arm Bench Press is a medium risk exercise when performed with proper technique. The shoulder takes most of the strain, especially at the bottom of each rep where the chest and front of the shoulder are stretched under load. The one-sided weight adds a twisting pull that can roll the body toward the working arm and drag the shoulder out of its stable position on the bench.

Keep the elbow angled about 45 to 60 degrees from the torso rather than flared straight out, lower only to the side of the chest, and keep the shoulder blade pulled back against the bench with the wrist stacked over the elbow. Choose a weight you can lower slowly while both hips and both shoulders stay flat, and bring the dumbbell into and out of position close to your body, since the setup is where many dumbbell mishaps happen.

If you can't stay square, hold the edge of the bench with your free hand while you learn the movement, or switch to the Dumbbell Single-Arm Floor Press, where the floor limits how deep the elbow can go. Once every rep is steady, progress by adding load gradually or by pausing briefly at the bottom.

Stop if you feel sharp or pinching pain in the front of the shoulder, pain deep in the chest or near the armpit, or numbness or tingling down the arm, and see a qualified clinician if it persists.

Overview

Primary Focus: Chest
Equipment: Dumbbell and bench
Modality: Strength
Difficulty: Intermediate

Alternative Exercises

Frequently Asked Questions

Q: What should I do with my free hand?: Let it rest at your side next to the bench, relaxed. Holding the edge of the bench makes it easier to stay balanced and is a sensible way to learn the movement, but it takes away some of the trunk work, so let go once you can stay square without it.
Q: How much weight should I use compared with the regular dumbbell bench press?: Start with less than you hold in each hand for a two-dumbbell press. Staying level on the bench is usually the limit, so pick a load you can lower slowly on every rep without your hips or shoulders rolling.
Q: How is it different from the Alternating Dumbbell Bench Press?: In the Alternating Dumbbell Bench Press the other hand holds a second dumbbell at arm's length, which partly balances the body, while here the free hand is empty and the trunk has to resist the twist on its own. In a study of recreationally trained young adults doing one-arm presses on a flat bench, holding only one dumbbell let them move through a larger shoulder range of motion than holding a second dumbbell up in the other hand.
Q: Should I finish all reps on one side before switching?: Yes, that is the usual way to program it, and it keeps the trunk working for the whole set. Many trainers start with the weaker side and match its reps on the stronger side, so the gap between sides does not grow.
Q: Can it replace the regular dumbbell bench press?: It can stand in for it in a program, but because balance limits the weight you can use, most lifters do it alongside a two-arm press like the Dumbbell Bench Press rather than instead of it.