Biceps curls can be done using any of the following equipment:
- E-Z bar (also known as a "Bent bar")
- Cable machine
- Biceps curling machine
- Nautilus equipment
Although the exercises differ, a common factor of each is a 'curling' motion, where a weight—attached to an item of equipment listed above—is moved through an arc, primarily using the strength of the biceps. The biceps is contracted to lift the weight upward through the arc, to a point where further movement is not possible. It is important that the elbow remain next to the body during this motion as to keep stress on the biceps. The biceps is then extended, lowering the weight back through the arc, to the start position. This contraction and extension together constitute a single repetition.
Several variations on the biceps curl transfer some of the load from the biceps to other flexors of the elbow. One group of variations involves postures that hold the elbows in front of the trunk, shortening the biceps and forcing the brachialis to do more work. Variations on this theme include the preacher curl where the elbows rest upon a sloped bench, the concentration curl where the elbow is braced against the inside of the knee, and the prone incline curl performed lying prone on an inclined bench, where the force of gravity holds the upper arms in front of the trunk.
The biceps curl is usually performed with the palms supinated (facing upwards). Turning the palms inward transfers load from the biceps to the brachioradialis. Variations on this concept include the hammer curl, performed with the palm inward, neither pronated nor supinated, and the reverse curl, with the palms pronated (facing downwards). Another variation, the Morelli Curl uses a traditional over-under or powerlifting grip with one palm supinated and the other pronated. The concentric component of the lift is emphasized in the pronated arm, while the eccentric component emphasizes the supinated arm.