If you’re happy with the hardness, shape and thickness of your upper arms, then keep up what you’ve already been doing. On the other hand, if you feel like one or more areas of your biceps could use some improvement, then incline cable curls may be just the stimulus that your fibers need to activate the signaling pathways that will reshape your arms.
Incline cable curls activate both heads of the biceps brachii muscle. The long head begins on the scapula and it crosses the front part of the shoulder joint.1 It has a very long tendon, but a shorter muscle belly than the short head of the biceps brachii. The belly of the long head of the biceps sits on the lateral part of the arm, and its fibers combine with the short head as both sets of muscle fibers extend towards the elbow. The short head of the biceps begins on the coracoid process on the anterior part of the scapula (shoulder blade).1 It extends down the inner part of the humerus bone and joins with the long head of the biceps, to form the bicipital tendon. This tendon crosses the anterior part of the elbow joint to anchor on the radius bone of the forearm. Both the long and the short heads of the biceps strongly flex the forearm.1 However, because the bicipital tendon inserts on the laterally positioned radius bone of the forearm, the biceps also acts to supinate the hand (turns the palm towards the ceiling), when it contracts.
The brachialis muscle lies deep to the biceps brachii. It begins on the distal half of the humerus and it inserts on the coronoid process of the medially placed ulna bone of the forearm.1 Although it has no supination function, it is a very strong flexor of the elbow joint.
THE EXERCISE: INCLINE CABLE CURLS
1. Adjust the incline bench to about 60 degrees.2 Place the bench in the middle of a pulley station that has two low pulley attachments.
2. Attach the single handle to the low pulley and take one handle in each hand. Choose a medium, light weight (one you can do for 15 reps) to start with until you get the feel of the movement. Sit on the bench and press your back firmly against the bench.
3. Turn your palms so they are supinated (palms facing forward). Keep the hands supinated throughout the exercise. In the starting position, your arms should be stretched out to the sides and you should feel a good stretch across the shoulder. This position ensures that the origins of both heads of the biceps are in a stretched position, and this will increase the activation of the fibers in the biceps.
4. Keep your upper arm (humerus bone) in this position, then flex the elbow of both arms so the hands move up to the shoulder. This will provide a better activation than if you did the exercise one at a time.3 Remember that only the forearm and hands should move as you contract the biceps and brachialis muscles to pull the cable handles upwards as far as possible. Exhale as the handles are moved upwards.
5. Slowly lower the cable handles until the elbow is almost straight (extended). Inhale as the hands are going down. At the bottom position immediately move upwards for the next repetition.
SETS & REPS
Shoot for 10-12 repetitions, with a medium weight, for 3-5 sets. Rest about 60 seconds between sets.4
If you want a little different feel to the exercise that will focus a bit more on the short head of the biceps, you can try to lower the bench to 30 degrees.2 The brachialis does not cross the shoulder joint, so it is not affected by the shoulder position or bench angle and works pretty much the same in any arm curl exercise.
- Moore, KL and AF Dalley. Clinically oriented Anatomy. Fourth edition. Baltimore, Lippincott Williams & Williams, 1999; 665-669; 720-733.
- Moon J, Shin I, Kang M et al: The Effect of Shoulder Flexion Angles on the Recruitment of Upper-extremity Muscles during Isometric Contraction. J Phys Ther Sci 2013;25:1299-1301.
- Serrau V, Driss T, Vandewalle H et al: Muscle activation of the elbow flexor and extensor muscles during self-resistance exercises: comparison of unilateral maximal cocontraction and bilateral self-resistance. J Strength Cond Res 2012;26:2468-2477.
- Oliveira AS, Goncalves M: Neuromuscular recovery of the biceps brachii muscle after resistance exercise. Res Sports Med 2008;16:244-256.