Stand with the back straight, grasping the barbell with an underhand grip and hands slightly wider than shoulder-width apart:
• Inhale and raise the barbell by bending the elbows, taking care to stabilize the torso and spine by isometrically contracting the gluteal muscles, abdominal muscles, and spinal muscles.
• Exhale at the end of the movement.
This exercise mainly contracts the biceps brachii, brachialis, and, to a lesser degree, the brachioradialis, pronator teres, and the wrist flexor group.
Comment: When training the biceps brachii using a barbell, take into account variations in each person's physical structure. In the anatomical position (arms hanging alongside the body, palms facing forward, and thumbs pointing laterally), the angle at the elbow between the upper arm and the forearm varies from person to person. Someone whose forearm hangs distinctly away from the body in a valgus position must break excessively at the wrist when performing a curl with a straight bar, which is painful. Therefore, these people should work with an E-Z bar to spare their wrists.

Variations: Vary the width of the grip to work different parts of the muscle more intensely:
• Placing the hands farther apart isolates the short head of the biceps brachii.
• Placing the hands closer together isolates the long head of the biceps brachii.
Raising both elbows after they are flexed increases the contraction of the biceps brachii and contracts the anterior deltoid. To make the exercise more difficult, perform the movement with the back against a wall so that the shoulder blades don’t move. You can lift more weight and gain strength by leaning the torso back while lifting the bar; however, to prevent injury, this requires good technique and well-developed abdominal and lumbar muscles.
