Alternate Hammer Curl
Also works: Forearms
A standing curl with a neutral grip — thumbs up, palms facing each other — done one arm at a time. The neutral hand position takes the biceps out of its strongest line and hands the work to brachialis and brachioradialis, which is why hammer curls build arm thickness that supinated curls do not.
Own the movement
Set up first, then execute. Every cue below is something you can check on your next set.
Before the first rep
- Stand with feet hip-width, dumbbells hanging at your sides, palms facing your thighs and thumbs forward.
- Set your elbows against your ribs and leave them there — they are the hinge, not a moving part.
- Grip the handle dead centre. Let it slide toward the inner plate and the dumbbell tips, and your wrist ends up holding it rather than your arm.
- Start from fully straight arms. A hammer curl begun from a half-bent elbow gives away the range where the brachialis does most of its work.
- Pick a weight you can lift without shifting onto your back foot. If you have to rock, it is too heavy.
Every rep
Breathing & tempo — Exhale as you curl, inhale as you lower. One second up, a one-second squeeze, three seconds down — and hold that same tempo on the second arm, which will feel fresher and tempt you to rush it.
Sets, reps & load
Where to start, and what to change when it stops being hard.
Most people can hammer curl slightly more than they can supinated curl, because the brachialis is strong and the grip is comfortable — start around 8-12 kg if you already train, 5-6 kg if you do not. Add 2 kg when you can hit the top of your rep range on both arms with a one-second squeeze and a three-second negative. If one arm lags, do the weak side first and match the strong side to its count.
What goes wrong
The errors that show up most often, and the cue that fixes each one.
Stand with your back against a wall and your heels 15 cm from it. If your shoulder blades leave the wall, the dumbbell is too heavy — drop 2 kg and the cheat disappears.
Pin your upper arm to your ribcage and stop the curl when the forearm is vertical. If the elbow travels, you have swapped an arm exercise for a shrug with extra steps.
Keep the handle vertical from start to finish. Imagine you are holding a hammer and driving a nail into the ceiling — if the head would tilt, the grip has drifted.
Take three seconds on the way down on every rep. The lowering phase is where most of the brachialis growth comes from, and it is the part everyone skips.
Why bother
The biceps brachii supinates the forearm as well as flexing the elbow, so it contributes most when your palm is turning up. Hold the dumbbell vertically and you remove that job entirely. The brachialis, which sits underneath the biceps, and the brachioradialis, which runs along the thumb side of the forearm, take over. Build the brachialis and it pushes the biceps up from below — the arm looks thicker from the side, not just from the front.
Alternating is not just a way to pass the time. Doing one arm at a time lets you use a heavier dumbbell than you could control simultaneously, gives each arm roughly double the rest, and makes a strength difference between sides impossible to hide behind. The cost is that the set takes twice as long, which is why alternating suits your heavy arm work and simultaneous curls suit your burnout sets.
Where it fits
After your pulling work, or on an arm day, 2-4 sets of 8-12 per arm. Neutral grip is also the friendliest curl for a cranky elbow or wrist, so if supinated curls give you medial elbow pain, run hammer curls for a block instead of stopping arm work altogether. Once or twice a week is plenty — the biceps also get hit by every row and chin-up you do.
If this one isn't it
No kit, too hard, or too easy — here's where to go instead.
Same job, different kit
Start here instead
When this gets easy
Asked and answered
Hammer curls or regular curls — which builds bigger arms?
Do both. Supinated curls hit the biceps' short and long heads hardest; hammer curls hit the brachialis and brachioradialis, which add width when viewed from the side and push the biceps peak higher. Running only one of the two leaves visible size on the table. Two sets of each beats four sets of either.
Is alternating better than curling both dumbbells at once?
For heavy work, yes — each arm gets double the rest so you can use more load and hold form for longer. For metabolic finishers, curling both at once is more time-efficient and the extra fatigue is the point. Use alternating for your working sets and simultaneous for the last set if you want a pump.
Why do I feel this more in my forearm than my bicep?
Because that is largely correct. The brachioradialis in the forearm is a primary mover with a neutral grip. If it burns out before your upper arm, your grip may be the limiter — try a thinner handle or lighter dumbbells with a slower negative rather than fighting to feel it in the biceps.
Can I do these if my elbows hurt on normal curls?
Usually yes. Neutral grip puts less strain on the medial elbow tendons than a fully supinated grip, and it is the standard swap when biceps tendon pain shows up. Drop the load 30%, slow the negative, and if it still hurts, stop and get the elbow looked at rather than working around it for months.