How to do a bicep curl for stronger arms

A bicep curl is a great exercise to keep your arms looking toned, and to improve strength, but how do you do it? You’ll probably recognise the move – it's widely used and a staple of many gym workouts. Although it looks simple, the bicep curl needs to be done correctly to see the full effect.

There are many variations if a regular bicep curl with dumbbells doesn’t work for you – experiment with different grips and equipment, such as barbells, resistance bands and a cable machine.

How to do a bicep curl

Exercise: Bicep curl

Equipment needed: Dumbbells

Level: Beginner

Areas worked: Primarily biceps, but also triceps, forearms and grip

How to do a bicep curl:

• Make sure you have completed a warm-up before starting to exercise.
• Stand tall, with your feet firmly planted about hip-width apart, chest lifted and tummy tight.
• Hold a pair of dumbbells at your side, palms facing out.
• Keep your shoulders relaxed (remember, shoulders and ears aren’t friends), elbows tight to your sides.
• Squeezing the dumbbells, curl the weights up by bending your elbows, until they come nearly to your shoulders.
• Keeping the same level of tension, lower the weights back to the starting position, then repeat.
• Try to exhale as you curl the weights up, inhale as you lower them.

What weight should I use?

When it comes to strength training, you should always aim to pick a weight that is challenging, but not impossible. If you’re going to complete 10 repetitions of a bicep curl then the weight should feel hard by the time you’re at your seventh repetition. By number 10, you should need to rest.

At no point should the weight be so heavy that you arch your back, dip your knees, or swing the weights to curl them up.

How many repetitions should I do?

The exact number of repetitions (reps) depends on how heavy the weights are, the style of training, and what your goals are.

If you go to a fast-paced class involving dumbbells or barbells (such as Body Pump), you might lift lighter weights for more reps, while a dedicated strength workout in the gym may use heavier weights for fewer reps.

Assuming you’re doing your own workout in the gym, 3 sets of 8-12 reps at a medium weight works well for beginners, with 60 seconds rest between sets.

If you want to feel the benefits of strength training then you need heavier weights with fewer reps – a 5 x 5 approach works well (5 sets of 5 reps). Rest should be longer, as your muscles will need more time to recover – around two minutes.

Should I do single or double arm?

There’s no right or wrong answer, as it depends on your ability, goals and preference. Often bicep curls come towards the end of a workout, because you should always work in order of larger muscles down to small. The biceps are small compared to, say, the muscles in your chest or shoulders.

So, if you are short on time, curling both arms together takes up less time than doing them individually. It also means you expend less energy, so it could help if you’re tired.

On the other hand, curling one arm at a time means you can potentially lift a heavier weight as you’re only putting the energy into moving one weight. You can also concentrate on that one arm.

If you have an impingement that means you can’t lift as heavy a weight on one side as the other, my advice would be to go with the lower weight for both arms, regardless of whether you’re lifting together or not. It’s good to strengthen both arms at the same rate, letting the less strong side catch up before you progress to the next weight.

It’s always good to mix bilateral and unilateral (both-sided and one-sided) exercises into your workout. You might not feel it, but your core has to work harder to stabilise you in a single-sided move, so try to mix things up.

Common mistakes and how to avoid them

Here are some things to watch out for when performing a bicep curl:

Using momentum

The important element of a bicep curl is that the biceps do the work. Using the shoulders or torso to “swing” the weights won’t have the desired effect, which is to get stronger biceps. If you find you need to swing the weights then they’re too heavy: set them down and pick up lighter ones.

Focus on keeping a firm core and standing upright. Keep your shoulders in line with the body – don’t allow them to move forward to start the movement.

Going too fast

A bicep curl isn’t an exercise in speed. We want our muscles to work so they become stronger. Rushing the exercise means your biceps don’t get a chance to fully elongate and contract. It’s this motion that makes them stronger.

Focus on a steady one-two-one-one-two: two seconds to raise the weight, pause one second, and then two seconds to lower the weight. As you advance, you can play around with these tempos to work the biceps further.

Letting the elbows wander

During a bicep curl, the elbows need to stay tight to the sides to isolate the biceps (make them do all the work). Only the lower part of your arms should move until the top of the movement (when the weight comes near to your shoulder). At that point, the elbows will naturally move forward slightly, then return to position as you lower the weight.

Shrugging your shoulders

I’ve said it before, but it bears repeating: shoulders and ears aren’t friends. When lifting weights, it can be tempting to shrug the shoulders to help lift the weight. But that won’t achieve anything other than creating tension in your neck, and it definitely won’t help build stronger biceps.

Often people aren’t even aware they’re doing this, so it can be useful to look in a mirror as you’re performing the exercise until you’re comfortable with the movement.

Variations and modifications

If you’re bored of using dumbbells for bicep curls, or they present any issues, why not try one of these variations?

• Barbell curl – load a barbell with moderately heavy plates and perform the curls as above. Spreading the weight across a bar means you can lift a heavier weight.
• Cable machine – use a straight bar attachment on the cable machine, with the cable at the bottom of the machine. Pull the bar to waist height and start the movement from there.
• Resistance bands – stand on the band with feet hip-width apart. Hold the handles or end of the band firmly by your thighs and curl.
• Hammer curl – use dumbbells as detailed above, but hold the weights in a “fist grip” instead, knuckles facing forward, palms facing in.
• Reverse curl – using lighter dumbbells, hold them in an overhand grip, palms facing behind you. Curl the weights up and back as detailed above.

A sample biceps workout

Try this combination of moves:

• Barbell curls: three sets of 10-12 reps. Rest 60 seconds between sets.
• Single arm dumbbell bicep curls: three sets of eight reps per side (alternate arms). Rest 45-60 seconds between sets.
• Reverse curls: three sets of 10-12 reps (lighter weight). Rest 45-60 seconds between sets.