We all want big biceps. When talking about muscles, the first image that comes to mind is to bend the upper arm to see how big the peak is. You want to make that peak bigger, otherwise, you won't be reading this now. You also want to use exercises that have been proven effective.
EZ bar curl is like that. Champions of every era have used it, and many people in the fitness world are now using it. It is the main exercise of many biceps training, if you haven’t already, you should do it.
Muscles worked

Although curls are exercises that focus on the biceps, they involve several muscles of the upper arm. This is a short description of each one.
Biceps
The biceps brachii or biceps brachii is the main muscle group that is exercised when curling hair. It is the two muscles located in the front of the upper arm, used to supinate or rotate the forearm so that the palm is facing upwards, and play a secondary role as the elbow flexor.
In addition, because the biceps passes through the shoulder joint, it plays a small role in shoulder joint flexion.

Brachialis
The brachialis is located below the biceps on the outside of the upper arm. Therefore, when well developed, this muscle helps to create more width for the upper arm.
The main function of the brachialis is to flex the elbow.
All the curl changes exercise the brachialis to some extent, but using a more neutral grip seems to activate it best.
Brachioradialis
Brachioradialis is a forearm muscle that can make the forearm supination and pronation, but it is also the elbow flexor. When the forearm is pronated/palm down, it has a mechanical advantage over the biceps.
How to do the EZ bar curl?
1.Stand upright and hold the outer part of the curved rod. The palm is forward and slightly tilted inward following the shape of the curved rod. The elbow is close to your torso. This will be your starting position.
2.Keep your upper arm fixed, exhale and contract your biceps to lift the weight, and focus on moving your forearm.
3.Continue to raise your forearm until your biceps are fully contracted and the bar is at shoulder level. Peak contraction for one second and squeeze the biceps.
4.Then breathe in and slowly return to the starting position.
6.Repeat the action to the recommended number of repetitions.
Variation: You can also use a curved rod to connect to the lower pulley to complete this action. This change will provide a good feeling of peak shrinkage.
Benefits of the EZ bar curl
The EZ bar curl arm will rotate internally, which will stimulate the long head of the biceps a little more, the angle of the EZ bar will change, and the pressure on the wrist joint will be relatively less. Therefore, the contraction of the short head is limited, but the long head is elongated, which stimulates the outside of the biceps muscles stronger, and the risk of injury is also lower.
If you are new to training then save yourself aches and pains later and start using the EZ bar now. Make sure you are using proper form and you don't use a weight that is so heavy you must cheat or swing to lift it.
EZ bar curl Variations
Reverse curl

The EZ barbell reverse curl will allow you to truly activate the brachioradialis muscle to the fullest extent and exercise the muscles on the knuckle side of the forearm. You won't be able to use that much weight, but this is a very good chance because you can use a more natural grip compared to using a straight bar.
Preacher curl

The promise of the preacher curl is simple: you’ll get bigger biceps. Studies show that during this type of curl, activation of the bicep is at its maximum due to the support of the preacher bench, so it helps you build muscle.
Back and Forth Curl
To practice back and forth, you need a training partner.
One of you will set the challenge and the other will accept it, back and forth, until neither of you can continue.
This exercise can cause severe biceps pumps but is not suitable for the faint-hearted.
Related More:
Bicep curl guide
Dumbbell curl
Barbell curl
EZ bar curl
Preacher curl
Hammer curl
Reverse curl
Zottman curl
Concentration curl