EZ Curl, Straight Bar Curl and Prone or Hammer Curl
Bicep curls are bicep curls right? Wrong. All bicep curls are not created equal. This does not mean one is necessarily better than the other because they are different entirely in what muscles they target within the upper arm. It would be smart and beneficial to you to incorporate all types into your training.
First of all lets consider the musculature and anatomy of the arm, more specifically the upper arm and elbow joint. What most average gym goers would identify as his/her biceps muscles actual consists of two muscles, the biceps brachii and the brachialis. In addition to thinking that the bicep is the only muscle that is on the anterior portion of the upper arm, most people also think it is the king of elbow flexion. However, this is not so. The brachialis originates on the distal half of the humerus and inserts on the coronoid process and ulnar tuberosity, thus making its sole purpose elbow flexion. The brachilias is deep to the biceps breachiiThe biceps brachii originates on the surpaglenoid tubercle and inserts on the radial tuberosity. While the biceps brachii also can perform elbow flexion, the nature of its attachment leads it to have an alternative personality, that alternative personality being the action of supination. A note which will be important for the duration of the rest of this article will be to picture supination as palms up and pronation as palms facing down.
Now lets relate your daily dose of anatomy of the anterior upper arm to your weightlifting. The straight bar or barbell is used for all kinds of exercises. We want to focus on the barbell curl first. When you curl the barbell in a straight bar curl, your forearms are fixed in a supine position. In addition to being in a fixed supine position they also have no option of pronation, and cannot deviate from this supine position at all. The barbell actually acts as a stopping point for extra supination. Because you are curling the bar for an extended time, say 12 repetitions, your biceps brachii are constantly trying to continue to supinate the forearm even more, but the bar acts as a block to this. For this reason, sometimes the wrists begin to hurt if the weight is too extensive because the wrists begin to try and counteract this constant supination force and begin to weaken and tire. Because of the radial insertion of the biceps brachii, to flex the arm it first must act to supinate the arm. Barbell curls with the hands fixed in a supinated position therefore target the biceps brachii.
Next lets look at the prone curl. Because the forearm is pronated in a prone curl this, for all intensive purposes, “deactivates” the innervation of the biceps brachii. By pronating the forearm the biceps brachii no longer have an optimal line of pull due to the nature of the insertion on the radius. However, the brachialis has no radial insertion and therefore is not effected whatsoever by the pronation and supination of the forearm. That being said, when performing a prone curl you are isolating the brachialis when performing the exercise. The straight bar curl however, does not isolate the biceps brachii because the brachialis will still be involved due to the fact it is not effected by the pronation or supination of the arm.
The EZ curl bar exercise is more conducive to those who have wrist problems as opposed to using the straight bar. The EZ curl does not necessarily target the brachialis over the biceps brachii. By but allowing for only the slight supination of the forearm instead of the extensive supination as the straight barbell curl, there is less tension place on the wrist during this exercise.
So, as far as biceps curls goes, just be aware as with any other exercises that you perform, to change up the type of exercises you do. Vary your workouts and vary the exercises you do. This allows you to target all muscles that are involved in the movements of the body. This is also why you shouldn’t just do your favorite exercises because as I once heard “the best exercises are the ones you aren’t doing”. Can’t remember where and who I have heard that from but the idea is of the upmost important. Change your workouts from week to week and be aware of your body position while performing each exercise.
Sources:
http://www.exrx.net/Muscles/BicepsBrachii.html
Kemerly, A. (2008). Biomechanics: Analyzing human movement.
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