by Brad Schoenfeld T-Nation
Here's what you need to know...
You need to focus on working muscles from different angles based on the orientation of the individual fibers.
Muscular recruitment varies based on the plane of movement in which the body is worked. It's amazing how many lifters seem to miss this fact and train almost exclusively in the sagittal plane.
The claim made by some that all you need to do are the "big lifts" is overly simplistic, at least if your goal is maximum muscle.
Even something as simple as using different hand and foot positions can enhance hypertrophy by targeting different muscles and or portions thereof.
Proper manipulation of program variables is essential for maximizing muscle development. Most often, lifters focus on the all-important aspects of intensity and volume, and rightly so. These variables have a profound impact on adaptations, but an often overlooked factor central to results is varying exercise selection.
Make no mistake: If you fail to include a variety of exercises in your routine, you'll fall short of getting the most out of your muscular potential.
To be clear, variety here has nothing to do with "muscle confusion" or any such overhyped propaganda. Rather it's about working your muscles in a manner that promotes optimal stimulation of all fibers. In fact, one of the primary reasons that bodybuilders are thought to have greater muscular development compared to powerlifters and weightlifters is the variation of training they use. While strength athletes mainly stick with a limited number of lifts, physique athletes employ a multitude of exercises.
The importance of variety is apparent from basic functional anatomy. Muscles often have varied attachments that help to optimize leverage for varying actions. For example, the trapezius is subdivided into an upper aspect that elevates and upwardly rotates the scapula, a middle segment that adducts the scapula, and a lower aspect responsible for depressing the scapula. Similarly, the deltoids have three distinct heads anterior, middle, and posterior that carry out flexion, abduction, and horizontal extension, respectively.
Okay, so perhaps this isn't news to you. What you might not be aware of is the fact that varying exercise selection can potentially allow you to work portions of the same fiber. Contrary to popular belief, fibers do not necessarily span the entire length of the muscle from origin to insertion.
Muscle fibers are often partitioned into neuromuscular compartments with each compartment innervated by its own distinct nerve branch. Studies show that the biceps brachii, sartorius, gastrocnemius, and hamstrings, amongst others, are all subdivided by one or more fibrous bands or inscriptions. This has important implications for targeting different body parts.
What's really interesting, though, is an emerging body of research showing that the selective activation of different areas of a muscle is consistent with where hypertrophy occurs in that muscle. Translation: Emphasizing activation of given aspects of a muscle can enhance the extent of hypertrophy.
A key takeaway here is that maximal muscular adaption can only be achieved by fully working all aspects of all the major muscles, and this can only be accomplished by training with a variety of exercises.
The bottom line is that by taking a scientific approach to varying exercise selection, you'll be able to construct a workout plan that optimizes the overall size and symmetry of your physique. Here are five strategies to accomplish this task.
1. Alter the Training Angle.
Fibers contract optimally when they're placed in direct opposition to gravity along the direction of the fiber. This means you need to focus on working muscles from different angles based on the orientation of the individual fibers.
For example, the pectoralis major is partitioned into the sternocostal and clavicular heads. The sternal head best opposes gravity when you're lying supine, while the clavicular head is more aligned with gravitational forces when the torso is inclined. This is consistent with EMG studies showing that the sternal head is maximally activated during performance of the flat press and the clavicular head receives greater stimulation at a moderate incline. Take home message: both variations should be incorporated for optimal chest development.
Training angle also must be considered when working the deltoids. Most people think that the shoulder press is primarily a middle delt developer. Not so! Because the shoulder joint is externally rotated during performance, the anterior delt is placed in a position to directly oppose gravity and it thereby receives the majority of stimulation. The middle and posterior heads are substantially less active.
To target the all-important middle delt, you need to employ movements where the shoulder is somewhat internally rotated such as the lateral raise and upright row.
For the lateral raise, make sure that your pinky is higher than your thumb as you lift; otherwise, your shoulder will be externally rotated, placing the anterior delt in opposition to gravity.
For the upright row, assume a wide grip to maintain focus on the middle delt and only come up to parallel to avoid risking impingement.
2. Work in Different Planes of Movement.
Humans are three-dimensional beings. Our bodies are designed to carry out movement in each and every direction. The musculoskeletal system is able to call upon different muscles based on the directional requirements of a given task. Therefore, muscular recruitment changes, based on the plane of movement in which the body is worked. It's amazing how many lifters seem to miss this fact and train almost exclusively in the sagittal plane.
A multi-planar approach is particularly important to work the muscles of the back. While the lats are highly active in frontal plane exercises such as pull-ups and lat pulldowns, the mid-traps and rhomboids have their greatest activation in sagittal plane rowing movements where maximal shoulder hyperextension can be achieved. Moreover, transverse plane exercises such as wide-grip rows and bent flyes are needed to optimize stimulation of the posterior delts.
Multi-planar training is equally important when working the legs. Sure, squats, lunges, stiff-leg deadlifts and leg presses are staple exercises, but including exercises such as lateral lunges, resisted lying clamshells, and other frontal plane movements provide complementary activation patterns that bring about greater development of your lower half.
3. Manipulate the Length-Tension Relationship.
A muscle fiber's ability to produce force is dependent on a concept called the length-tension relationship. Simply stated, the contractile capacity of the fiber is dictated by the position of the actin and myosin filaments in its sarcomeres. There are two strategies you can use to take advantage of this phenomenon in your training: active insufficiency and passive tension.
Active insufficiency refers to the condition where a two-joint muscle is shortened at one joint while a muscular contraction is initiated by the other joint. Because of the weak contractile force of a muscle when its attachments are close together, the muscle is at its lowest point on the length-tension curve and therefore its capacity to produce force is diminished.
Conversely, passive tension is achieved when a two-joint muscle is elongated at one joint while producing force at the other joint. This produces a favorable length-tension relationship and therefore maximizes the capacity of a muscle to produce force. As an analogy, think of a slingshot. You can propel an object a lot farther when the rubber band is taut than when it's slackened.
Having an understanding of these concepts allows you to selectively target areas of your physique by making muscles more or less active during movement. The classic example of employing this strategy is with training the calves. As you know, there are two primary calf muscles the gastrocnemius and the soleus. The gastroc is a biarticular muscle, crossing both the ankle and knee joints. At the ankle, the gastroc is a plantarflexor (i.e. extender of the ankle) while at the knee it assists the hamstrings in flexion.
When performing a seated calf raise, the gastroc is rendered actively insufficient since the knee is flexed. Accordingly, it has limited ability to produce force leaving the soleus to carry out the majority of the work. Alternatively, standing calf raises place the gastroc in a stretched position whereby it produces maximum force.
The triceps are another muscle that lends itself to this strategy. Since the long head is an extensor of the shoulder joint, it becomes stretched in shoulder flexion and therefore can exert more force than the other two heads.
Overhead triceps extensions therefore are best for long head development.
Conversely, the medial and lateral heads are more active during movements where the elbows are held at the sides. This renders the long head less active so that the remaining heads carry out a greater amount of work. Thus, an exercise such as the triceps pushdown will allow for maximal involvement of the lateral and medial heads.
4. Combine Multi- and Single-Joint Exercises.
Without question, compound exercises are essential components of any muscle-building program. They dynamically work large swaths of muscle and statically involve numerous stabilizers as well. That said, the claim made by some that all you need to do are the "big lifts" is overly simplistic, at least if your goal is maximum muscle.
During performance of multi-joint movements, some muscles will necessarily make a greater contribution to movement than others. For example, it's often assumed that the hamstrings are highly active during compound lower body exercises. Not true. Research shows that hamstring recruitment is markedly lower than that of the quads and glutes when performing the squat and leg press.
This is consistent with the biarticular structure of the muscle complex. You see, the hammies are both hip extensors and knee flexors. During compound lower body exercise, the hips and knees flex during the eccentric phase and extend during the concentric phase, meaning that the resting length of the hamstrings really doesn't change much throughout the movement. This necessitates performing single-joint exercises such as Romanian deadlifts, good mornings, and leg curls to ensure optimal hamstrings development.
Similar principles apply to the upper extremities, where the biceps and triceps long heads also have biarticular structures. Sure, you'll get substantial activation of the arm muscles during performance of upper body presses and pulls, but as with the hamstrings, the length of these muscles will remain fairly constant throughout performance. Targeted single joint exercises for the biceps and triceps afford the potential for stronger muscular contractions and thus greater growth.
Take home point: Although multi-joint exercises should form the foundation of any hypertrophy-oriented routine, single-joint movements can have a synergistic effect on muscular gains.
5. Use Different Hand/Foot Positioning.
Even something as simple as using different hand and foot positions can enhance hypertrophy by targeting different muscles and or portions thereof. For example, studies show that assuming a wide stance while squatting increases activation of the gluteus maximus and the adductors while a narrow stance results in a greater stimulation of the plantarflexors.
Similarly, a narrow hand spacing in the bench press results in significantly greater activation of the clavicular head of the pecs compared to a wide grip. There's even evidence that foot position can influence calf activation; turning the feet inward targets the lateral head of the gastrocnemius while turning the feet out targets the medial head.
Architectural variances between and within muscles dictate the importance of adopting a multi-planar, multi-angled approach to hypertrophy training utilizing a variety of different exercises.
Moreover, given the need to fully stimulate all fibers within a muscle, it would seem that a fairly frequent exercise rotation is warranted to maximize the hypertrophic response. Just make sure you take a scientific approach to exercise selection so that the movements combine synergistically to optimize size and symmetry.