The bicep curl is an isolation weight lifting exercise in which a dumbbell is lifted by bending the elbow upwards towards the shoulder.
This isolation lift can also be performed using a bicep curl machine.
What muscles does the bicep curl use?
The bicep curl is an isolation exercise which targets the bicep muscle in the front of the upper arm. The exercise also works the brachialis, which is a muscle situated beneath the bicep, assisting it at the elbow joint.
The shoulder (deltoid) and upper chest (pectoralis major) work as fixator muscles, aiding the bicep with stability control.
This lift is the simplest exercise to perform to increase bicep muscle and improve definition.
It is a good idea to combine bicep curls with tricep extensions to balance the muscle development. This is important because muscles work in pairs and the opposite muscle to the bicep is the tricep.
This means that to develop the bicep muscle and not exercise the tricep muscle would result in risk of injury with one side much weaker than the other.
It will also look better aesthetically to have both sides of the upper arm equally well developed.
Bicep curl machine
By using the bicep curl machine, you can gain a more stable control than using free weights because the upper arm is rested and held in place.
This simple machine is better for new weight lifters but after you are practised, you may want to move onto performing bicep curls with free weights.
With free weights, you need to make sure the upper arm is not moving and trying to ‘help’ by giving momentum to lift the weight. The bicep is the only muscle that should be worked strongly when performing bicep curls.
There is also the preacher curl bench that is useful for a controlled curl. Again, this bench helps the lifter to keep their upper arm stable and concentrate on the bicep as the working muscle.
Preparing for the bicep curl
Good bicep curl technique means ensuring you perform the lift correctly from start to finish – this will get you the best results the fastest. To prepare for the bicep curl using free weights, stand or sit with one dumbbell in each hand. Start with palms facing forward.
Hold abs tight and keep your back straight with a neutral spine. Breathe in, then as you breathe out again, begin your lift either using one at a time (unilateral lift) or both hands together (bilateral lift).
To prepare for the bicep curl using a bicep curl machine, sit on the seat with spine neutral against the back rest and feet flat on the floor.
Rest the backs of your upper arms on the pads and reach down to grip the handles with an underhand grip.
You can also use both styles of lift together, starting in the hammer curl position and when you reach the top of the lift turning your wrists around to finish in the bicep curl position. This can help you get both benefits and target all muscles in the bicep/brachialis area.
Performing the bicep curl
To perform the bicep curl using free weights, slowly lift the dumbbell up and as it comes higher, rotate your wrist so that your palm faces inwards towards your shoulder. Finish at the top of the lift by your shoulder.
Slowly lower the weight in the opposite way, rotating your wrist back so that the dumbbell finishes by your hip where it started.
This shows good bicep curl technique with the combination of movements ideal for developing the bicep and brachialis,
To perform the bicep curl using the bicep curl machine, keep the backs of the upper arms pressed against the pads and bend both elbows to pull the handles upwards using an underhand grip. You will feel tension in your bicep.
When you are at the top of the lift, slowly lower the handles again to complete your rep.
Make sure you keep your upper arms still so that the only muscle working is your bicep and there is no help from the front shoulder (anterior deltoid). Keeping upper arms still is absolutely essential for good bicep curl technique.
There are various types of bicep curl that can all be performed for different benefits. You can use one arm at a time (unilateral lift) or both together (bilateral lift) when performing the bicep curl.
Bicep curl technique
When using free weights, keep your abs tight and back straight throughout the exercise. This helps to control your central body and allows you to concentrate on using the bicep muscles to lift the weight.
Upper arms should stay beside the body, with elbows tucked into your sides and shoulders should not raise up or move. Exhale as you lift the weight and inhale as you lower it.
The bicep curl using the bicep curl machine uses the same muscles as the free weight version. The machine makes the exercise a little easier as the pads help to keep your upper arm still.
Keep a smooth, slow and controlled motion throughout the lift. Focus on the bicep muscle and use only the bicep muscle to lift the weight without any swinging from the shoulders.
Common bicep curl errors
To improve your bicep curl technique, try to avoid these errors:
Moving the dumbbell too far back at the top of the lift. Don’t pull the dumbbell so far back that the forearm moves beyond your shoulder. The top of the lift should be so that your elbow is at just a bit more than 90 degrees. It is more important to focus on lowering the whole way, than lifting too high.
Lifting too quickly. You can easily lose form if you try to execute the lifts too quickly. The muscles get a better workout from a controlled, slow and steady lift. Concentrate on good form and feel the tensing of the bicep rather than worry about speed.
Using the shoulders and torso to help hoist the dumbbell upward. The shoulders (deltoids) and torso (abdominals and obliques) should not help lift the weight when doing the bicep curl. This can result in a twisting movement which can cause injury and strains. Put all the effort into the arms. It is better to use lighter weights or fewer repetitions if you find yourself heaving with your shoulders
Swinging the dumbbell with its momentum. This can by avoided by keeping elbows firmly at your sides.
Not lowering the dumbbell far enough on the downward motion. If you only move the dumbbell part way down during the lowering phase, this can result in a gap developing between the inner elbow crease and the start of the visibly developed bicep, with the bicep muscle more developed higher up on the arm.
A properly developed bicep muscle should be highly visible lower towards the elbow crease – this can be achieved by lowering all the way down until your arm is straight as you lower the dumbbell.
Concentrate on lifting with a slow, controlled motion and avoiding the errors above to achieve an excellent bicep curl technique.
Read more about types of bicep curl