You plant one hand on a bench and row a dumbbell with the other, then switch sides. Each arm gets its own turn. That setup can be useful without being a special muscle-growth upgrade: a 2026 review found no clear growth advantage simply from training one limb at a time.
The more useful distinction concerned the strength task being practiced. The finding points toward choosing a format for a specific goal, rather than assuming single-sided lifting is always better.
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No clear growth winner emerged
The systematic review combined 24 randomized trials involving 588 participants. Seventeen studies involved athletes, and the programs included resistance training, plyometrics and combinations of the two. This was broader than a comparison of two dumbbell-row routines.
The muscle-growth analysis found no statistically significant difference between unilateral and bilateral training. That evidence was rated low certainty, so it does not establish that every one-sided and two-sided exercise produces identical growth.
Strength results generally followed the practiced task: unilateral training favored single-limb tests, while bilateral training favored two-limb tests. The latter advantage was small and less stable in sensitivity checks. Programs and participants varied, limiting how confidently the findings transfer to your exact workout.
Count the work for each side
ACE’s unilateral-training guide lists single-arm rows, presses and curls among the options. “Unilateral” describes a single-arm or single-leg task; it does not simply mean holding one dumbbell. A goblet squat can use one weight while both legs perform the movement.
For your log, imagine three sets of 10 rows per arm. That means 30 repetitions on the left and 30 on the right. Three sets of 10 simultaneous two-arm dumbbell rows also give each arm 30 repetitions, even though the arms move together.
Those are counting examples, not proof that the exercises impose identical demands. Switching sides adds another working period to organize; it does not automatically double each arm’s work. Write “per side” clearly instead of comparing a combined rep total with a single-side total.
Keep the load, variation and support position in the log too. A bench-supported one-arm row and an unsupported two-arm row ask you to maintain different positions. Changing the exercise changes more than the number of hands moving.
Choose a reason for making the switch
The American College of Sports Medicine’s 2026 guidance recommends tailoring resistance training to the goal and making the program manageable enough to maintain. For muscle growth, its summary emphasizes weekly training volume; for strength, it highlights heavier loading. An exercise label alone does not describe the whole plan.
If improving a particular two-arm lift is the goal, keep that goal visible when choosing exercises and tracking progress. A one-arm row can remain another option without its dumbbell number becoming a direct prediction of your next two-arm lift.
If your current dumbbells are manageable but the next pair is too heavy, our guide to progressing before a large dumbbell jump explains another decision to consider. Moving to one side at a time is a format choice, not a requirement to force a heavier weight.
Before changing the next set, finish this sentence: “I’m choosing this version because…” Practicing a particular lift, fitting the available equipment or using a setup you can repeat gives the switch a clearer purpose than expecting the one-sided label to guarantee extra growth.