by Jim Cordova

Specialized Concentration

Is it possible to shift fiber emphasis in the biceps? More than all of the others, specialized fiber activation in this muscle group is a hotly debated topic. The fiber makeup of the biceps runs near-parallel down the humerus, extending the forearm in a single direction. To some, this signifies the futility of region-specific training. However, this is a very simplistic view from which to draw such drastic conclusions. To be more precise, elbow flexion relies on two distinct muscles, each consisting of innumerous fiber-like strands, crossing over two highly versatile joints, that don’t even shorten uniformly upon contraction!

I admit that the biceps are one of those muscle groups that possess a limited opportunity for region-specific stimulation. Since they work so closely together, every biceps movement will stimulate both heads to some degree, and complete isolation is impossible. On the other hand, their complex structure suggests that one of the two biceps heads will have a mechanical advantage over the other relative to the position of the arms and the path of tension. This means that you can shift stimulation within the muscles, ensure that you are working toward fuller biceps, and, to some extent, even alter their appearance!

In many cases, concentration curls consist of a mixed bag of region-specific ingredients that equate to nothing more than working both biceps heads with added volume and lighter weight. By selecting and combining the relevant variables, you can become more precise with regard to your objectives and accelerate growth. There are a few foundational models that will simplify your approach and assign a whole new meaning to your idea of concentration curls.

The first involves the stretch factor, which refers to lengthening and shortening the biceps from their fixed origination point on the scapula. This mainly affects overall fiber recruitment. It is controlled by bringing the elbows back behind the waist and elevating them toward the head, to lengthen and shorten the biceps, respectively. Generally, fiber recruitment peaks when the elbows are near the waste, with this position being ideal for stimulating hypertrophy. Curling with the elbows elevated results in a very dense contraction. This is a key position to advance separation between the biceps and supporting muscles and where I find contraction and strict isolation tactics to be very useful.

I am sure to surprise some of you when I state that varying grip style can be very counter-productive in your quest to sculpt your biceps. Because of the mechanical disadvantage arising at the point of insertion, overall activation of the biceps will gradually decrease upon rotating the wrists from the supinated toward the neutral and pronated positions. Basically, you will find no greater way stress the biceps than by taking a supinated grip.

Rotating the arms at the shoulder joint will better allow you to shift emphasis between the two biceps heads. This can be tracked by bending the arms at an angle and focusing on lower arm adduction/abduction. Though commonly gauged with grip-width, the point of focus should be hand placement relative to the elbows. The greatest activation from both biceps heads will occur when the hands and elbows are aligned at slightly less than shoulder-width vicinity, which is ideal for overall mass-building. Moving the forearms toward the midline will better allow you to focus on the outer head, and vice-versa.

The outer head performs to a higher degree than the inner head when curling with the arms nearly straightened until roughly 90-degrees of flexion. Conversely, the inner head will work harder from that point onward. Particularly when curling with free-weights, the brunt of the stress will occur when the forearms are parallel to the ground and positioning the angle of the upper arms will allow you to control where you want the bulk of the stress to be. You can shift the tension factor to the inner head by keeping the upper arms perpendicular to the ground and the outer head by slanting them, as you would during a preacher curl.

When performing concentration movements based on this notion, remain within three-quarters of the full ROM regardless of what head you are targeting. This is because both heads are strongly activated during the midrange and it is only about one quarter, at the very beginning or end, of the ROM that one is working harder than the other. Plus, you want to avoid violating the constant tension principle by aligning the lower arms with gravity. For example, you will find that stopping about one-quarter short of full flexion on preacher curls and a quarter short of total extension when performing standing barbell curls to be highly effective.

Ultimately, this should broaden your thinking, allowing you to combine the relevant factors to enhance every curling exercise and place extra stress on one of the two biceps heads. The EZ-bar preacher curl with a close grip is a great example since the components that maximize emphasis in the long head are built right into it. Yet, this is one of many highly effective combinations and the point behind the tactics discussed thus far is to get you to consider the relevant variables within the framework of the movement, as they are the key behind the benefits reaped from its implementation! Thinking along these lines will allow you to become much more strategic with your form and even afford you the opportunity to tailor each movement and enhance its effect.

Goal-Oriented Approach

Before you perform any type of movement, you should establish clear-cut objectives. For the sake of simplicity, the foundation of every exercise can be divided into extreme categories of growth or refinement. Within that framework, you can focus on overall or region-specific development when selecting exercises. Such clarification will increase efficiency, ensure thorough stimulation, and allow you to be more precise with the rep range, cadence, positioning tactics, and pertinent strategies.

It is advantageous to periodize your regimen in order to achieve your region-specific goals more rapidly. For example, if you desire to maximize your peaking potential, you could begin with exercises that apply extra focus to the outer biceps head and brachialis during two out of three individual biceps routines and follow that up with a workout devoted more toward the inner head.

Once you establish a general goal specific exercise pattern, you can apply slight twists to the basic form of each movement within that framework. For example, you can take barbell preacher curls and substitute it with dumbbell or cable preacher curls from one workout to the next. You can also take a single exercise and shift the position of the arms to vary fiber emphasis and the tension pattern every time that you use it. Though each exercise will have the same basic effect, making subtle adjustments will equate to enough of a change to keep the muscles from becoming resistant. Over time, the results add up to accelerated growth and fuller biceps when compared to using the same exercise format each week! Surely this is a much more intelligent approach, relegating a canned biceps regimen or even a simplistic understanding of curling from various angles, to an elementary mindset.

Below are two outstanding workouts geared toward rapid hypertrophy:

Outer head specialization (rep-range: 8-12):

1. EZ-Bar (or Cable) Close-Grip Biceps Row*

2. Close-Grip EZ-bar Preacher Curl

3. Shoulder-Width Standing Dumbbell Curl

4. Close-Grip Pulldowns

Inner head specialization (rep-range: 8-12):

1. Shoulder-Width (Preacher) Barbell Curl**

2. Wide-Grip Dumbbell Curl***

3. Standard Concentration Curl

4. Reverse-Grip Cable (or EZ-Bar) Curl ****

*Grip width should lie within elbow range, similar to a close-grip preacher curl. Be sure to extend arms until 10-degrees short of full extension.

**Position the upper arms on the steep end of the preacher bench so that they are perpendicular to the ground. The objective is to shift the brunt of tension throughout the second half of the ROM.

***Keep elbows near shoulder-width, the upper arms perpendicular to the ground, and let the hands flare out wide. Do not fully extend lower arms.

****It is more natural, effective, and recommended to let elbows flare out a bit during the lift.

The point of this article is to stir up your thoughts and get you to reflect upon the logic behind your exercise selection. At the very least, I hope to have inspired you to examine the relevant factors within the framework of every biceps movement, as they reveal the extent of its value with respect to your goals! Thinking along these lines will enable you to become much more strategic with your form and even afford you the opportunity to tailor each movement to increase its effect. As it stands, every exercise in my regimen is detailed with personalized twists and variations, as will yours upon taking the time to evaluate and implement the countless strategies available to you. Just as a sculptor becomes more acquainted with his tools and can enhance the beauty of his creations over time, you can better understand the connection between positioning and tension variations and how they affect the musculature of the human body, learning how to carve your physique into a work of art!