Does rowing one arm at a time even out a side-to-side difference?

It gives the weaker side its own work and its own load, which is a sound reason to program it, but the evidence that unilateral training closes a gap is thin. A 10-week trial in untrained women found that an upper-body program done one arm at a time produced no greater strength gains, in either arm, than the same program done with both arms. If closing a gap is the goal, row the weaker side first and give the stronger side the same number of reps, so at least the volume stays equal.

Does the single-arm version train the core?

Less than an unsupported row does. In a comparison of three rows in 15 trained men, the two-armed versions produced only about 40% of the external oblique activity of the same rows done one arm at a time, but all of those rows were done seated or standing, and here the hand and knee on the bench carry most of that twisting load. If the anti-rotation demand is what you are after, row one-armed from a standing position instead, such as the Cable Single-Arm Bent-Over Row.

How is this different from the two-arm dumbbell row?

The Dumbbell Bent-Over Row is a standing hinge, so your lower back holds the position for the whole set, while here the bench holds it for you. Rowing one side at a time also doubles the length of the set, and most lifters can row a heavier dumbbell supported on a bench than they can with both arms standing, so it is the better pick for loading the back hard and the worse one for finishing a session quickly.

Is Dumbbell Single-Arm Bent-Over Row suitable for beginners?

Yes. The bench makes it one of the easier free-weight rows to hold in a good position, which is why the standing versions usually send beginners here first. Start light enough that you can finish every rep without turning your torso, and add weight only once that holds for a full set on both sides.

Dumbbell Single-Arm Bent-Over Row

What Is the Dumbbell Single-Arm Bent-Over Row?

Dumbbell Single-Arm Bent-Over Row is a compound exercise that primarily targets the back, and it also loads the rear deltoid, the elbow flexors and the forearm that holds the weight. It is an intermediate-level movement performed with one knee and the same-side hand on a bench, so the bench carries most of the torso while the opposite arm rows a dumbbell from arm's length to the hip.

That support is what separates it from the standing rows. With a hand and a knee taking part of your weight, the spinal erectors no longer have to hold a loaded hinge for the length of a set, so the muscles being trained usually give out before the lower back does. It is the supported version of the Dumbbell Bent-Over Row and the Barbell Bent-Over Row, so it also works after either of them, once the hinge is already tired, or on any day the lower back is not up to a standing pull. As the main row of a session it usually sits early in a back or pull day, at roughly 8 to 12 reps per arm for size and 6 to 10 for strength.

Rowing one arm at a time changes three things. Each side is loaded on its own, so a stronger side cannot quietly take over and you can see exactly what each arm handles. Nothing spans the body, so the dumbbell travels past the line of the torso instead of stopping against it, which lengthens the pull. And because the free hand is on the bench, the trunk no longer has to balance the load, which is the trade this variation makes: more room to load one arm, less demand on the torso. Giving the weaker side its own work is a sound practical reason to program it, but treat evening out a side-to-side difference as a rationale rather than a promised outcome.

Where the dumbbell finishes decides the emphasis. The version shown here pulls to the hip with the elbow tucked and driven back past the ribs, which keeps the shoulder in extension and puts the work in the lats and teres major. Finishing higher, nearer the lower ribs with the elbow further from your side, hands more of it to the rear deltoid, rhomboids and traps. The same movement can also be run free standing, with the free hand on a bench or a rack and both feet on the floor, which is harder to hold still but keeps the hips level and square.

It suits anyone who wants to row heavy without asking the lower back to hold the position, and anyone working around a side-to-side difference in strength or a shoulder that dislikes a fixed bar. If holding a flat back over the bench is what fails first, start with a seated pull such as the Cable Seated Row and come back to it. Driving the elbow back toward your hip pocket, rather than lifting the dumbbell with your hand, is the cue that most reliably keeps the work in the back.

Muscles Worked

MuscleActivation

Latissimus Dorsi: Primary
Lower Trapezius: High
Rhomboid Major: High
Teres Major: High
Upper Trapezius: High
Biceps Brachii: Medium
Deltoid: Medium
Erector Spinae: Medium
Brachioradialis: Low
External Oblique: Low

Instructions

Set a flat bench beside you and stand a dumbbell on the floor next to it.
Place one knee on the bench and put the same-side hand flat on the bench under your shoulder, with that arm straight.
Plant the opposite foot on the floor beside the bench, roughly in line with the knee that is on it.
Reach down with your free hand and take the dumbbell with a neutral grip, palm facing the bench.
Set your back flat and close to parallel with the floor, hips level, neck in line with your spine.
Let the dumbbell hang at arm's length directly under your shoulder.
Pull it up toward your hip, leading with the elbow and keeping the upper arm close to your side.
Finish with the dumbbell beside your hip, the elbow back past your torso and the shoulder blade drawn in, without letting your torso turn toward it.
Lower the dumbbell under control until the arm is straight again.
Complete all your reps, then swap the hand, knee and foot and repeat on the other side.

Common Mistakes

Twisting to finish the rep
Turning the torso toward the dumbbell at the top is how a weight that is too heavy gets moved, and it puts the lower back under a twist while it is loaded.
Rowing with the hand
Pulling with the hand and biceps instead of driving the elbow back past the ribs leaves the lats doing very little of the work.
Finishing at the shoulder
Letting the elbow drift away from your side so the dumbbell ends up near the shoulder is a different row from the one shown here, and a much shorter one for the lat.
Pushing off the bench
Shoving down through the supporting hand to help the dumbbell up turns a back exercise into a whole-body heave and hides what the working side actually lifted.
Losing the flat back
Letting the lower back round or the hips sag between reps puts the spine in the one position the bench is there to keep it out of.
Cutting the bottom short
Stopping before the arm straightens trims the range the back works through, and it is the first thing to go once the dumbbell is too heavy.

Injuries

Dumbbell Single-Arm Bent-Over Row is a low risk exercise when performed with proper technique. The bench takes part of your weight and fixes the torso, so the lower back is not holding a loaded hinge the way it is in a standing row, and a rep that goes wrong can be ended by putting the dumbbell straight back on the floor.

The lower back is still the first thing to watch, because the load sits on one side of the body. Letting the back round at the bottom, or letting the working-side hip drop and then rotate up with each pull, turns a braced position into a twisted one while it is loaded. Keep your hips level and square to the bench, brace before each rep, and hold the same torso angle from the first rep to the last.

The shoulder is the second strain point, and it is the bottom of the rep that causes the trouble. Letting a heavy dumbbell drag the shoulder forward and then yanking it back out of that position is what leaves the front of the shoulder sore, so start each pull from a set shoulder blade and keep the elbow close to your side instead of letting it drift out away from your body. The supporting arm carries load through a bent-back wrist for the whole set, so if that wrist is what aches, grip the edge of the bench rather than laying the palm flat, or rest the forearm along the bench instead.

If the position over the bench is what limits you, a seated pull such as the Cable Seated Single-Arm Row or the Machine High Row trains the same movement with the torso fully supported, and the Barbell Inverted Row builds the position with your own body weight setting the load. Add weight only once every rep of a set finishes without the torso turning toward the dumbbell. Stop the set straight away if you feel sharp pain in the lower back or the shoulder, or any numbness or tingling running down the arm, and do not train through either.

Overview

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

Alternative Exercises

Frequently Asked Questions

Q: Does rowing one arm at a time even out a side-to-side difference?: It gives the weaker side its own work and its own load, which is a sound reason to program it, but the evidence that unilateral training closes a gap is thin. A 10-week trial in untrained women found that an upper-body program done one arm at a time produced no greater strength gains, in either arm, than the same program done with both arms. If closing a gap is the goal, row the weaker side first and give the stronger side the same number of reps, so at least the volume stays equal.
Q: Should the dumbbell come up to my hip or my ribs?: The version shown here brings it to the hip with the elbow tucked and driven back past the ribs, which holds the shoulder in extension and keeps the work in the lats. Finishing nearer the lower ribs, with the elbow further from your side, shifts more of it to the rear deltoid, rhomboids and traps. Both are usable rows, so pick one and hold it for the whole set rather than drifting higher as the weight gets hard.
Q: Does the single-arm version train the core?: Less than an unsupported row does. In a comparison of three rows in 15 trained men, the two-armed versions produced only about 40% of the external oblique activity of the same rows done one arm at a time, but all of those rows were done seated or standing, and here the hand and knee on the bench carry most of that twisting load. If the anti-rotation demand is what you are after, row one-armed from a standing position instead, such as the Cable Single-Arm Bent-Over Row.
Q: How is this different from the two-arm dumbbell row?: The Dumbbell Bent-Over Row is a standing hinge, so your lower back holds the position for the whole set, while here the bench holds it for you. Rowing one side at a time also doubles the length of the set, and most lifters can row a heavier dumbbell supported on a bench than they can with both arms standing, so it is the better pick for loading the back hard and the worse one for finishing a session quickly.
Q: Is Dumbbell Single-Arm Bent-Over Row suitable for beginners?: Yes. The bench makes it one of the easier free-weight rows to hold in a good position, which is why the standing versions usually send beginners here first. Start light enough that you can finish every rep without turning your torso, and add weight only once that holds for a full set on both sides.