Shrug Science: Part 1
by Paul Chek
A famous medical doctor, C. Chan Gunn, once likened the human upper trapezius muscle (Figure 1) to that of a cobra snake's hood. Just as the cobra snake will flare it's hood when angry or threatened, humans also flare their traps in a show-down situation. I'm sure many of you can remember seeing film clips or pictures of Bruce Lee posing in one of his many ready for action stances, where his traps would be flared. Most people would agree that his trap development was quite impressive for such a little man!
Figure 1 — The trapezius group has three functional divisions, the ascending portion or "upper traps", the middle portion, which has its fibers in the horizontal plane, and the descending portion or "lower traps". All three divisions are critical to optimal neck and shoulder function.
A man or woman with large, well-developed traps causes people to think, "Wow, that guy looks powerful," or, "That is one thick, rugged dude," or even, "Hmm? I wonder who wears the pants in her family?!"
Trap development is a sign of strength. It's uncommon to see a man or woman with developed traps that hasn't proportionately developed the rest of his or her body. More important than the aesthetics of big, well-developed traps is the injury prevention and performance enhancement they provide to an athlete or manual laborer. The trapezius group is critical to stabilization of the shoulder in any activity requiring use of the arm.
Trap development is also critical for performance and injury prevention in numerous sports. The trapezius group (upper, middle and lower) are key contributors to the force generating sequence during most pulling exercises and are critical to most power lifts, particularly the Olympic lifts.
Explosive efforts in contact sports, especially where tackling or checking is involved, rely on the synergistic action of the legs, trunk and traps. The shoulder is often the weapon of choice in tackling sports, but alone, it's not strong enough and does not have adequate amplitude of movement to inflict the intended punishment on an opponent.
Therefore, to compensate for the lack of strength, the force and amplitude of movement by the legs and trunk are transferred upward through the kinetic chain to the shoulder. Here, the massive leg and trunk forces must be carefully sequenced, such that they summate with those of the muscles above. The result of well-timed force summation at the shoulder, when appropriately delivered to an opponent's body, is well understood by anyone who has played contact sports or has watched them on TV!
It was demonstrated long ago that "for every action, there is an equal and opposite reaction." When the traps are used to lift heavy loads or when they are the end product of forces from below, there's always a risk that they may not be strong enough to do their job, or that they may fatigue prior to the muscles producing force below them. Unfortunately, because of our anatomical design, failure of the traps to do their job can result in injury to the neck, shoulder and the brachial plexus (the nerve bundle leaving the neck to feed the arm and shoulder).
Figure 2 — The brachial plexus (nerves feeding the arm) exits the neck and travels over the first rib and under the clavicle. The brachial plexus then traverses under the coracoid process and insertion of the pectoralis minor into the axilla (armpit) and down the arm. The trapezius and levator scapulae muscles are necessary to avoid unwanted compression of the brachial plexus by the clavicle as it passes over the first rib.
The upper trapezius is of utmost importance for the protection of the brachial plexus, serving to prevent postural loading of the traps. This is important, for example, when carrying a backpack (Figure 3), a brief case with a shoulder strap, or when handling heavy loads in the gym (Figure 4). During an impact, such as being slammed into the hockey boards (Figure 5),the shoulder is rapidly and forcefully depressed, placing both a stretch and compressive load to the brachial plexus. This often results in what is referred to by athletes and coaches as a "stinger" or "burner." I've had to serve as a consultant to several professional athletes suffering chronic neck and shoulder problems after repeated "burners" because they began to lose strength and muscle mass in the injured arm and shoulder.
The shrug exercise and its several variations are critical to conditioning the trapezius muscle group. When performed properly, the shrug exercise will build mass, improve neck and shoulder stability, improve overall power output, and serve as a vital source of injury prevention!
In Part I of this two-part article, I'll cover the kinesiology of the shrug and how to properly set up and perform the shrug to prevent injury and promote optimal trap development. I'll also cover acute exercise variables for people desiring trap endurance, strength hypertrophy, power, or all of the above.
Kinesiology of the Shrug Exercise
The upper trapezius muscles are very strong by nature and (with the exception of pure rehab cases and endurance training) need to be conditioned with heavy loads. It's not at all uncommon for an athlete to be able to shrug over 300 pounds. Even a wimpy fella can often perform shrugs with sixty-pound dumbbells in each hand.
Because heavy weights and high intensities of training are commonly used, a tremendous amount of load is transmitted through the body and to the ground during the exercise. Performing the shrug exercise with less than optimal form while using heavy loads can easily traumatize joint and ligament structures as well as magnifying existing muscle imbalance syndromes. Therefore, setting up for the shrug starts at the ground!
Setting Up for the Shrug
If structures inferior to the rib cage aren't functioning optimally, there will not be an optimal environment for the shrug exercise. Due to the insertion of the trapezius muscle at the occiput (base of the skull), the head and neck serve as the foundation from which the traps produce the force of shoulder elevation. However, the rib cage is part of the foundation for the head, neck and shoulder girdle.
Therefore, the rib cage should be considered to be the foundation for the shrug exercise (Fig. 6). Before explaining the importance of the interactions of the shoulder girdle and rib cage, it's important to understand how to position and utilize the anatomical structures below the rib cage as they pertain to shrug set-up and rib cage stability.
Figure 6A — When performing the shrug exercise, it's critical that you avoid letting the shoulders or head move forward. If such forward migration of the head and shoulder complex is allowed, there's excessive compression, torsion and sheer placed on the acromioclavicular and sternoclavicular joints. Over time this can lead to painful degenerative changes such as clavicular osteolysis.
Figure 6B — When the shrug is performed correctly, the load is equally distributed throughout the entire rib cage, shoulder girdle and head/neck complex (also see figure 9B).
As illustrated in Figure 7 A-B, the following key alignment points must be addressed while performing a shrug:
• Feet parallel and weight distribution equal between balls of feet and heels. The stance width is such that the feet are within the vertical space occupied by the pelvis or just slightly wider. If the dumbbells are dragging on your outer thighs, your stance is too wide.
• Knees bent to approximately 20 degrees and aligned over toes.
• The umbilicus is drawn inward to activate the transversus abdominis (TVA) adequately to stabilize the spine, but not so much that it detracts from respiration. The heavier the load or greater the training intensity, the greater the magnitude of TVA contraction needed.
• The shoulder girdle should be balanced over the rib cage with the arms hanging in the middle third of the body when viewed from side. The first rib angle of the chest should be elevated adequately to reduce thoracic kyphosis to the position of axial extension (making yourself as tall as you can); picking up the chest to a point just inside full inspiration will provide an optimal first rib angle for the shrug. This favors load sharing through the entire rib cage and minimizes loading of the AC and SC joints.
• The head should be positioned such that the zygomatic arch (prominence of cheekbone) is directly over the clavicle. The eyes should be level with the horizon and the gaze slightly above horizontal.
• The tongue should be in the physiological rest position to ensure optimal stabilization of the neck (Figure 8). Physiological rest position of the tongue is just behind the front teeth on the roof of your mouth. To find the physiological rest position, you need only swallow and note where your tongue goes.
Figure 8 — The tongue and anterior neck musculature have a much greater mechanical advantage over the posterior neck musculature. Their ability to resist the large forces of extension at the head-neck junction during the shrug is greatly improved when the tongue is held in the physiological rest position. This position can easily be achieved by noting where your tongue goes when you swallow.
While it may seem inconsequential, maintaining physiological rest position of the tongue during the shrug is critical to neck stability. The tongue musculature is part of a comprehensive stabilization system composed of deep and superficial muscles anterior to the cervical spine (Figure 9A).
Figure 9A — If the lifter allows the shoulders to round and the head to come forward during the shrug, the line of gravity moves forward, as indicated by the dotted arrow. Such faulty head and shoulder position predisposes the middle and lower cervical vertebra to excessive sheer forces because the fibers in this region (C3-C6) are optimally arranged to elevate the load from this position.
Because the large and powerful upper trapezius muscles and levator scapulae muscles attach behind the center of gravity of the cranium, their action compounded with the force necessary to elevate the shoulder girdle under the loads used during the shrug will produce posterior rotation of the cranium and protrusion of the head-neck complex in the sagittal plane (front to back).
If the head and neck are repeatedly subjected to the protrusion and retraction under load, microtrauma to the musculoskeletal structures of the craniocervical region and upper thoracic spine can easily lead to chronic pain and dysfunction in the upper quarter (jaw, head, neck and shoulder). In other words, don't thrust your head out in front of your body while performing a shrug!
As demonstrated in Figure 9B, when the superficial and deep cervical flexors work synergistically to antagonize the forces generated by the powerful scapular elevators as used during the shrug, the cervical spine maintains optimal load bearing relationships, as does the shoulder girdle with regard to the rib cage.
Figure 9B — With the head in optimal position, the load of the shrug is distributed effectively throughout the musculature of the anterior and posterior neck, shoulder girdle, rib cage and the remainder of the body. Note that when the head is carried correctly during the shrug exercise, the line of gravity falls in line with the vertebral bodies and discs of the cervical spine, allowing the load to serve as a stabilizing force, not a destructive force as is the case in Figure 9B.
With the ideal start positioning, the body is now aligned to afford maximum joint stability and there will be minimal neurological inhibition from joint mechano-receptors secondary to pathological levels of compression, torsion or sheer. We are now ready to begin the shrug.
The Ideal Shrug
Now that you have the correct starting position, you are in position to reap an optimal neuromuscular training effect from the shrug exercise:
• Begin with an inhalation. This will facilitate extension of the spine and elevation of the shoulder girdle due to respiratory mechanics. When shrugging in rep ranges greater than 6-8, inhalation coupled with shoulder elevation may serve to supply adequate respiration for the duration of the set.
When shrugging with high intensities or rep ranges of less than 6RM, you will be best served to fully inhale, draw the umbilicus inward, perform the concentric phase of the shrug (elevation of the shoulders) and then exhale through pursed lips as you lower the load. Begin each rep with the same respiratory sequence for optimal performance.
• With your thoracic cavity fully charged (post inhalation) and your body optimally aligned, elevate the shoulder vertically, or directly toward the ear. NEVER let the shoulder migrate forward into protraction while performing the shrug! This encourages FHP (forward head posture), causes excessive and unwanted loading of the sternoclavicular and acromialclavicular joints, and results in faulty load sharing in the rib cage, favoring an increased first rib angle (depressed chest).
This leads to crowding of the brachial plexus via narrowing of the thoracic outlet and if done repetitively in a training program, often results in scalene hypertrophy which further crowds the brachial plexus.
If the shrug is terminated in the same faulty position, there will be crowding and often compression of the brachial plexus under the clavicle at the first rib. Should one continue to perform the shrug in this faulty (yet common) manner, muscle imbalance throughout the entire body may be initiated and/or exacerbated!
An Ideal Shrug Modification
• When performing the shrug, it is advantageous to retract the scapulae during the eccentric phase of the exercise. Although this could be done during the concentric phase, it's more efficient to do it during the eccentric phase due to the heavy loads commonly used during shrugging.
As such, it is generally more efficient to lift the weight as vertical as possible and retract the scapulae while lowering the weight. However, should the shrug be used as a corrective exercise, the load can be lifted and/or lowered comfortably while inducing scapular retraction.
• Retraction of the scapulae during the shrug as suggested above, conditions not only the elevators of the shoulder girdle, but the retractors, which are commonly weak. Because many exercises, such as the squat, loaded lunges, dead lifts, pressing exercises and all Olympic lifts are heavily dependent on the shoulder elevators and stability of the shoulder girdle, it's logical to couple the motions of scapular elevation and retraction, facilitating this most useful combination of motor pathways.
Programming and the Shrug Exercise
Why use the Shrug?
The shrug should be used for increasing shoulder girdle stability, recovering from an injury to the brachial plexus or shoulder, improving postural correction, or enhancing aesthetics. The shrug is an important accessory exercise for those desiring maximal performance in pulling, pushing, or Olympic lifts.
When should the shrug be used?
The shrug can be used in any phase of a conditioning program (base, transition, or specificity), but if muscle mass development is the goal, it's best used in a base-conditioning phase.
If used during a specificity phase in concert with lifts such as the power clean, it must be carefully periodized to prevent overtraining of the scapular elevators which could potentially breakdown or lose performance during more complex lifts.
If used during the specificity phase, it should be regarded as an assistance or accessory exercise that should never be performed prior to primary lifts that depend heavily on shoulder girdle stability, particularly during pulling movements.
How should the shrug be sequenced?
Bodybuilding — The shrug is best trained on days when the chest, shoulders and triceps will be conditioned. Care should be taken not to schedule heavy upright rows, deadlifts or Jefferson Squats the day after a shrug session or performance may suffer and injury is of greater likelihood due to the level of shoulder girdle strength and stability needed for those exercises.
On days when shoulder training is scheduled, perform all overhead pressing, shoulder abduction exercises and any fly exercise (other than a DB fly) prior to the shrug exercise. Failure to do so will encourage faulty biomechanics of the shoulder secondary to fatigue of the upper trapezius, levator scapulae, and related scapular fixators and elevators. This will not only escalate your chances of injury during this training session, but your future training sessions as well.
Sports Conditioning — The shrug exercise should follow all other compound free-weight exercises. It's also best done prior to any machine exercises if performed from the functional standing position. The exception to this rule will come when the shrug exercise is the only exercise performed in a single session.
Those conditioning for sports in a transition phase (moving out of base conditioning and into specific conditioning) or a specificity phase must take special care not to fatigue the traps and shoulder girdle elevators too close to a training session that requires skilled use of the shoulder girdle under a significant load. Such training sessions would include hammer throwing, Olympic lifting, wrestling, grappling, shot put, or contact sports where the shoulder girdle is used as an offensive or defensive implement.
In situations as those described here, it may be optimal to sequence heavy shrugging and shoulder girdle training after practice, on the same day. This allows for optimal performance during training and adequate rest time between practice sessions. It will therefore allow a more effective work-to-rest ratio. Days of working the shoulder girdle contain both technical and non-technical work while the following day(s) provide rest to the relevant shoulder girdle musculature.
Acute Exercise Varriables
The human body is quite effective at adapting to specific exercise variables, hence the principle of "specific adaptation to imposed demands", or SAID principle. Although the shrug exercise is an exercise of almost universal application, manipulation of acute exercise variables can greatly influence the conditioning response in the relevant musculature.
Let's look at how to modify acute exercise variables for improving the performance of shoulder girdle elevators and stabilizers in some common situations.
Postural and Endurance Exercise Variables
The trapezius muscles are very important muscles for both postural fixation and stabilization of the shoulder girdle. Although the upper trapezius has been said to be silent during relaxed upright posture, there is an increase in activity that correlates to the load being held in the hand(s) (1).
The ability to maintain optimal postural relationships is critical to muscle, ligament, tendon and joint health, particularly in those with chronic exposure to repetitive or prolonged loading of the upper extremity in work or sports environments.
Should you or a client have early fatigue and discomfort while performing duties where the traps come into play (laying bricks, holding a child, etc.), application of the shrug exercise with appropriate acute exercise variables for improving postural endurance may be of great benefit.
Some of you may be experiencing tingling or numbness in the little finger and/or ring finger. This is a symptom of brachial plexus compression and these symptoms often arise when the lower cord of the brachial plexus is being abnormally stretched or compressed.
To improve your ability to stabilize the shoulder girdle, your acute exercise variables must allow adequate time under tension to fatigue the Type I (slow twitch) and Type IIA (fatigue resistant fast twitch) muscles.
According to research by Telle (2, 3), Type I fibers will fully fatigue in 3-5 minutes under optimal loading conditions (less than 40% maximum intensity) and generally recover in less than 60 seconds. Type IIA fibers will fatigue in 30-120 seconds (at approximately 40-70% maximum intensity) and will recover in 30-120 seconds.
Type I fibers are optimally loaded at intensities of less than 25% of one's maximum resistance (4), while the intensity of co-contraction type exercises designed to improve one's capacity to stabilize and stiffen joints may be ideal at 30-40% maximum voluntary contraction (5). Type IIA fibers are optimally recruited in intensity ranges of greater than 25% and less than approximately 60% according to Hartmann-Tunnemann.
The best way to apply this information to the shrug exercise for improving postural and joint fixation capabilities is to perform the exercise at slow tempos, such as three seconds up and three seconds down, or six seconds time under tension per repetition. If you are in a work environment such as brick laying or wallpaper hanging, you will be best served to perform the exercise for between 120 seconds and 300 seconds, or five minutes per set.
This would require that you perform shrugs very slowly (303 tempo) for between 20 and 50 repetitions. The rest period used should not be longer than 60 seconds in either case (20-50 reps). If you fatigue to the point that you can't achieve at least 90% of the total time under tension of your first set, discontinue the exercise for that training session.
Use one set to begin with and eventually progress to three sets per workout as post-exercise soreness decreases to tolerable levels between training sessions. Endurance training with the shrug exercise can be performed as frequently as every other day. If you are continuing to work or perform activities that require use of the shrug muscles during the day, it is best to perform the exercise at the end of the day or you may predispose yourself to injury secondary to muscle fatigue and inability to stabilize the shoulder girdle and neck!
Now, before we move on to conditioning for improved strength/endurance, it's CRITICAL that you always perform the shrug exercise in a position of perfect postural alignment as described in the beginning of the article. Performing the exercise in poor posture, as is so commonly done in the gym, will only train your brain to recruit the muscle group from that aberrant position!
Strength / Endurance Exercise Variables
It's generally accepted that the repetition window for strength/endurance training is 12-20 repetitions. Anything less than 12 reps is moving toward maximal strength and anything greater than 20 reps is moving toward pure endurance (3).
The optimal rest period for the shrug exercise when exercising in the 12-20 repetition range will have an inverse relationship to the number of repetitions. For example, the rest period for a 12-rep set should be 1 minute and as the number of repetitions increases, the rest period will decrease to as little as 30 seconds at the 20-repetition range.
Tempo will dictate total time under tension, which will ultimately influence the conditioning response over the repetition range selected. Keeping the total time under tension (TUT) near or below 60 seconds will facilitate strength development while a TUT greater than 60 seconds will progressively produce a greater endurance response. The best way to select the best TUT for your shrug exercise is to analyze the activity you plan on training for and determine if your use of the shrugging muscles will be needed for shorter periods of higher output or longer periods of endurance.
The total number of sets for the shrug when using strength/endurance loading variables is between 1-4, depending on your level of experience and overall level of conditioning. A good rule of thumb is the more repetitions performed during each set, the less total sets performed.
Hypertrophy Training Variables
The hypertrophy zone or "bodybuilding zone" is generally recognized to be 8-12 repetitions with rest periods of one minute. The number of sets performed for hypertrophy should be at least three and can be as many as six in the advanced athlete or experienced weight lifter. Time under tension or total work time should be kept below 60 seconds per set for optimal results.
It's apparent when observing the trapezius development of Olympic lifters that explosive lifting techniques that load the traps with 1-3 reps per set induce hypertrophy. While the beginner and intermediate (1-2 years) bodybuilder may obtain significant trapezius hypertrophy using a standard bodybuilding approach, the more advanced lifter is likely to see another phase of development when cycling between periods of high intensity (1-4 reps) with periods of traditional bodybuilding (8-12 reps). I've been able to make significant gains in muscle mass around the neck of football players in as little as 6-8 weeks.
For the athlete competing in a sporting event, particularly an event requiring punishing practice sessions, it's important not to perform too much hypertrophy-type training during the season. The training related fatigue could easily result in increased susceptibility to injury, which will ensure poor trap development!
Maximal Strength Variables
Maximal strength is defined as "the heaviest mass (or other external resistance) with which an individual can perform one repetition" (4). Maximal strength training is often used in periodized cycles because of the stress placed on the body, particularly the hormonal system and joints. Maximal strength training requires optimal hormonal profiles; therefore it's best not to perform this form of training longer than 30-45 minutes per training session.
Although the term "maximal strength" relates to your 1RM, cycling blocks of training in the 1-4 RM and 4-6 RM loading zones effectively develops maximal strength. If the lifter lacks muscle mass, a period of hypertrophy conditioning will be necessary prior to, or in concert with maximal strength training.
It's much more common to use a fast or explosive tempo with maximal training as it's the fast twitch fibers that have the greatest capacity for hypertrophy. Additionally, maximal strength is far more applicable to competitive weight lifting and sports requiring high levels of strength than it is to bodybuilding. That's not to say bodybuilders shouldn't use maximal strength training; it may be just what is needed to get over a training hump. However, they should be well conditioned and experienced prior to attempting this form of training if injury is to be prevented.
As the number of sets increases the number of repetitions go down. If you are going to do more than four sets, it's important not to perform more than 3-4 exercises per training session. Twelve to fifteen sets is about the maximum that will fit into a good training session and not crash the hormonal system.
In Part II of this article, I'll conclude the Acute Exercise Variable section by covering Power Training variables. Also, I'll introduce several different and useful variations of the shrug exercise and their specific applications.
The shrug exercise is often considered to be a staple exercise in a general conditioning or bodybuilding program. Because heavy loads are often used, and because the exercise requires tremendous loading of the head-neck-shoulder complex, exquisite detail must be paid to exercise form! The shrug exercise is very useful for the prevention of numerous injuries including those to the neck and brachial plexus. It's also used as a corrective exercise for such injuries as stingers as well as postural corrections for the upper quarter complex.
About the Author
Paul Chek is founder of the CHEK Institute in Encinitas, CA. He has served as a consultant to professional and college sports teams, equipment manufacturers and professional athletes worldwide. He is an internationally recognized lecturer and educator in the fields of orthopedic rehabilitation, corrective and performance exercise.
For more information about Paul Chek, his internship program or to request a catalog of his books, videos and products please call the location nearest you (see below), or visit his web site at ChekInstitute.com.
Australia and New Zealand: 0-800-552-8789
1. Basmajian, J. V. andDeLuca, C. J. Muscles Alive: Fifth Edition. Baltimore: Williams and Wilkins, 1989.
2. Telle J., Beyond 2001. Denver, CO: Edict Publishing, 1994.
3. Chek, P. Program Design, correspondence course and video cassette series. Encinitas, CA: A C.H.E.K Institute publication and production, 1995.
4. Hartmann, J. and Tunnemann H., Fitness and Strength Training for All Sports. Toronto: Sports Books Publisher, 1995.
5. Richardson, C., Jull, G., Hodges, P., Hides, J. Therapeutic Exercise for Spinal Stabilization in Lower Back Pain. London: Churchill Livingstone, 1999.
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