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Dumbbell · intermediate · shoulders

Dumbbell kneeling single arm arnold shoulder press

Also called Half kneeling Arnold press, Single arm Arnold press, One arm kneeling Arnold shoulder press, Kneeling Arnold press.

The short answer

An Arnold press performed half kneeling, with one dumbbell instead of two. The rotation is what sets it apart: the palm turns as the dumbbell rises, so the middle head takes a share that a straight press leaves to the front, and the elbow finishes it. What the single arm adds is a load sitting to one side of you, so your trunk has to keep your chest square and stop you leaning away from it. That is a description of the position rather than a claim about what it trains.

How to do it

  1. Step oneKneel on one knee with a dumbbell in the hand on the side of the raised knee.
  2. Step twoHold the dumbbell in front of your shoulder with your palm facing you and elbow bent.
  3. Step threePress the dumbbell upward while rotating your palm outward.
  4. Step fourFully extend your arm overhead with your palm facing forward.
  5. Step fiveReverse the motion to return to the starting position.
  6. Step sixComplete all repetitions on one side before switching.

What usually goes wrong

Each starts with what you would notice.

You tip away from the dumbbell as it passes your head.

WhyAll of the weight is on one side, so leaning the other way is the cheapest way to stay balanced. It also shortens the distance the dumbbell has to travel.

FixKeep both shoulders level and let the arm do the reaching. Judge it against a vertical line behind you, a door frame will do, rather than by feel, because a lean registers as effort and not as tilt.

Your free hand ends up on your thigh, pressing down on it.

WhyA hand on the leg gives you something to push against, so part of every rep comes from that arm bracing rather than from the working shoulder pressing.

FixHold the free arm out to the side, as the demonstration does, or let it hang. If your balance only works with a hand on the thigh, take weight off until it works without.

The second side cannot do what the first side did.

WhyNothing has gone wrong. The weight was chosen for whichever arm went first, and the second one is being asked to match a number that was never set for it.

FixLet the weaker side decide the reps for both, or press with it first so it picks the dumbbell. What you should not do is make the last reps happen by leaning, which is the fault above.

What it is for

The kneeling single arm arnold shoulder press is a unilateral shoulder exercise that incorporates the rotational movement of the arnold press to target all three deltoid heads. Performing it kneeling removes lower body stability and increases core engagement.

Questions people ask

Which knee goes down, and does the dumbbell go on the same side?
The demonstration loads the arm on the same side as the knee that is down, with the opposite foot planted in front. The written steps say the reverse. Both arrangements are used in practice, neither version has been tested against the other, and no professional body prescribes one, so pick an arrangement and keep it the same on both sides.
What does the Arnold press work here?
The front of the shoulder drives it, the middle head takes more than it would in a straight press because of the rotation, and the triceps finish. The Arnold press entry covers what the rotation does and what it does not.
Why press one arm at a time?
Because the load then sits to one side of you, which makes holding your position part of the exercise. It also stops a stronger arm quietly carrying a weaker one. Measured in 15 healthy men standing on two feet, pressing one arm at a time produced roughly two-thirds more activity down the sides of the trunk than pressing both, and what nobody has tested is whether half kneeling adds anything on top of that.
What should the free arm do?
The demonstration holds it straight out to the side at about shoulder height, which gives you something to balance with and keeps it off your leg. Letting it hang is fine too. What it should not do is push down on your thigh, because that turns into help.
Why kneel?
It takes your legs out of the press and leaves you less to balance on. The usual follow-on claim, that this therefore trains your core, has not been tested against standing or seated pressing, so it is worth treating as a description of the position and nothing more.
Is a single-arm press worth doing if you own two dumbbells?
It is a different exercise rather than a substitute. Two dumbbells let you load the shoulders more heavily in the time you have. One dumbbell asks you to hold your position while a weight off to one side tries to turn you. If pressing strength is the goal, press with both.

Also works delts