The word “yoke” traces its roots back to Sanskrit, believe it or not. Just as it is today, it was the name for the bow-shaped restraints that bound together pairs of oxen. The tool migrated from the fertile fields of the Indus River Valley to neighboring regions across the globe, and it is still in use today. The resemblance and position of the yoke to the human upper back gave rise to its use as a tailor’s term. This measure runs across the top of the torso from the end of one clavicle to the other. The yoke, however, isn't a pure width measurement since it follows the ridge of the torso. In fact, the yoke is actually a shallow arc made deeper by the trapezius. Barring surgery or Synthol, if you want to "embiggen" your yoke, then you need to “raise your ridge” by enlarging the trapezius.
The trapezius is a kite-shaped muscle that runs from the back of your head all the way down to the middle of your back. Along the way, it attaches to your skull, spine, clavicles, and scapulae. Strength enthusiasts are probably most familiar with a traditional model of the trapezius that divides the muscle into thirds. In this model, the upper portion includes the prominent rounded sections that sit on either side of the neck and the near-vertical fibers that run along the cervical spine (sometimes called the “descending" portion). These fibers elevate the shoulders/scapulae and extend the neck. The middle portion consists of horizontal and near-horizontal fibers between the scapulae and works with the rhomboids in retracting the scapulae. The lower portion has fibers angling out and up from the spine and, in balance with the rest of the muscle, is often called the “ascending” portion of the trapezius. For yoke enthusiasts, the upper fibers and the top portion of your middle fibers are the most important for your goals. These fibers are in the right position and are also the trapezius fibers most capable of growing.
This traditional model hits the highlights, but it doesn't engage the nuances of the trapezius and the resulting training accommodations that should be considered. First of all, the use of three divisions isn't entirely satisfactory. Holtermann et al. identified four distinct neuromuscular compartments within the trapezius. Each of these compartments can be activated without calling any other compartment into play. This finding doesn't completely scrap the three-part model, though. To the contrary, there are some visible commonalities. Using the concept of neuromuscular compartments, what the traditional model calls the "upper" trapezius is split into two components: it retains the descending portion that runs down the neck but distinctly names the fibers running along the edge of the torso (essentially the yoke line) the “clavicular” traps. This newer model allows for these two sections to operate independently of each other. This may be an important feature for lifters, as the trapezius can help extend the neck. Not being able to separate neck extension from scapular movement could actually interfere with normal shrugging movements. Tilt your head back and try shrugging to see this for yourself. The remaining portions keep the same locations and the fiber orientation names of “transverse” and “ascending.”
The trapezius’s relative lack of elevation power means that it doesn't work in isolation. Instead, it contracts in conjunction with the levator scapulae. The levator scapulae originate at the cervical spine, run along either side of the neck, and connect to the scapulae. This gives them a near-vertical line of pull that’s excellent for elevating the shoulders. Unfortunately, the placement and size of the levator scapulae mean that they contribute to neck thickness, but they won’t have much impact on yoke size.
Here we find the murkiest element of the trapezius: just how involved is it during common shrugging exercises? If Johnson’s right, then the answer is “not much.” EMG tests would normally provide a clear-cut answer, though some studies show heavy trapezius involvement during shrugs and others don’t. This leads some physios and PTs to believe that this variable trapezius data has more to do with interfering signals from the supraspinatus or the levator scapulae. On the other end of the spectrum, coaches and lifters of all stripes swear by close-grip barbell shrugs and dumbbell shrugs for trap development. I think there are valid elements to both arguments which I’ll attempt to weave together.
Regarding the EMG discussion, it’s important to remember that every EMG study on the shrug exercise shows some increase in trapezius activity during the movement. It’s the degree of activation, however, that’s up for debate. Is it a relatively weak co-contraction, or is it a powerful contributor to the movement? The contention is that surface EMG techniques are to blame for signal problems and resulting faulty data. Surface EMG places electrodes directly on the skin and measures broad areas of activity. Critics argue that fine-wire/intramuscular electrode information showing lower trapezius activity during shrugs is more accurate. This isn’t a guarantee, however. The fine-wire approach requires exact placement; thus, misplaced wires are far more likely to be masked by interfering signals or to miss active muscles entirely. Moseley et al., for example, used fine-wire techniques in their studies of the shrug but didn’t publicize placement location, therefore making it harder to verify their methods. Given that it’s a promoted practice to use surface EMG when analyzing trapezius activity and fine wire for the deep neck muscles (Rudroff), I think the burden of proof is on the contrarians.
I think some of the mixed data might also be attributed to shrug technique. In the gym, shrugs are usually performed with low reps and an explosive motion. This means that during the eccentric portion of the lift, the scapulae are yanked below neutral, which in turn calls the clavicular fibers into play, especially with one-armed shrugs. Lifters also unintentionally put their arms into slight abduction during shrugs just by flaring their lats. Activating the lats is a stabilization technique that also pushes the arms away from the body. Again, this abduction is more prominent with dumbbell variations. Lifters using one-armed shrugs also have a tendency to dip and lean into the movement, which can exaggerate both scapular positioning and arm abduction. Since arm abduction has consistently shown an increase in trapezius involvement, this could help account for an active role by the trapezius during the shrug.
Another aspect that is particularly true with barbell shrugs and Olympic movements is that lifters display loose body alignment during these movements. Usually the head moves forward to give the clavicular traps room for “bunching” atop the neck, and it’s common for this to coincide with a rounded thoracic spine or a slight forward lean at the hips in order to help a bar clear or to brace a free hand against a dumbbell rack. This position thus calls upon the clavicular traps to help retract the scapulae. Squeezing at the top only enhances the effect. This ability to retract the scapulae is a big reason why rows and face pulls stimulate the traps, particularly when there’s an emphasis on bringing the shoulders back during the concentric portion and pinching the mid-back. While I haven’t seen any data on it, I think the muscles that connect directly to the humerus generally fatigue before the traps in most rows. This would explain why rows aren't considered primary trapezius builders.
Returning again to the Moseley study, the lifters used very light weights and a tempo reflective of the rehab environment. They also lifted while seated and while maintaining a tight, upright posture. This is practically the opposite of shrugs in the gym. A later study by Ekstrom et al. made a point of using a five rep-max weight in a more conventional position. The one-armed dumbbell shrug, for example, is demonstrated by a subject displaying distinct body lean and shoulder displacement caused by bearing the weighted implement. Unlike Moseley’s earlier work, this study identified shrugs as a top trapezius exercise. Similarly, Jensen and Westgaard’s work, while being another study with seated participants, recorded significant trapezius activity during shrugs involving maximal unloaded isometric efforts.
I wouldn't be surprised if a few of you were wondering where deadlifts fit in. As it turns out, the trapezius is a tremendous stabilizer, as you’d expect of such a large muscle with so many functions and various attachments. It keeps the shoulder sockets tight and the scapulae fixed during pulling movements. It also transfers force away from the cervical spine. In fact, Escamilla et al. demonstrated that overall upper trapezius activity during conventional and sumo deadlifts was higher than in the glutes, hamstrings, and spinal erectors, and Abbott and Richardson demonstrated that the shoulder joint essentially caves in when the upper trap is treated with Botox. The traps also receive great deal of time under tension during deadlifts, shrugs, carries, and squats. The ultimate example would probably be the static barbell hold, which is generally performed with loads even greater than the deadlift.
Physique enthusiasts could use EMG knowledge to assist in developing upper back balance and symmetry. For example, competitive bodybuilders seeking to bring the rest of their frame up to par with their trapezius development could drop active trap work like shrugs and rows in order to focus on bringing up the middle deltoids, lats, and rotators, while maintaining the trapezius itself with spillover effects from deadlift variations.
Strength athletes like powerlifters could engage these lifts in parallel by picking and choosing various lifts to aid different needs. A rotational focus during prehab work could develop overhead presses or help resolve shoulder issues. Static holds, on the other hand, could help grip, ab strength, and lockout issues with the deadlift. Shrugs, rows, and face pulls situated on upper body-focused days would increase arch and shoulder tightness during the bench press.
Unlike most “show” muscles, there isn't a single lift for the trapezius that combines load, stretch, and full range of motion. (i.e., the factors most-often cited as essential for consistent hypertrophy). This complicated milieu reinforces another truism of yoke development: it takes time. To quote Jim Wendler, “Be patient and the rewards will be great.”
*You may have seen this called a “monkey shrug,” as it was dubbed by Adam Meakins.
Resources
- Abbott and Richardson, 2007. Abbott Z., Richardson J.K.” Subacromial impingement syndrome as a consequence of botulinum therapy to the upper trapezii: a case report”. Arch Phys Med Rehabil 2007; 88:947-949
- Ekstrom et al. “Surface Electromyographic Analysis of Exercises for the Trapezius and Serratus Anterior Muscles.” J Orthop Sports Phys Ther. 2003 May;33(5):247-58.
- Escamilla et al. “An electromyographic analysis of sumo and conventional style deadlifts.” Med Sci Sports Exerc. 2002 Apr;34(4):682-8.
- Holtermann et al. “Selective activation of neuromuscular compartments within the human trapezius muscle.” J Electromyography and Kinesiology 2009; 19: 896–902
- Jensen and Westgaard. “Functional Subdivision of the Upper Trapezius Muscle during Maximal Isometric Contractions.” J. Electromyography and Kinesiology. 1995: 5: 4; 221-237
- Moseley et al. “EMG analysis of the scapular muscles during a shoulder rehabilitation program.” Amer J Sports Med 1992; 20: 128-134
- Pizzari. “Modifying a shrug exercise can facilitate the upward rotator muscles of the scapula.” Clinical Biomechanics 2014; 29: 2: 201-205
- Rudroff. Kinesiological Fine Wire EMG: A Practical Introduction to fine wire EMG applications. Noraxon, 2008
- Struyf et al. “Scapular positioning and movement in unimpaired shoulders, shoulder impingement syndrome, and glenohumeral instability.” Scand J Med Sci Sports 2011; 21: 352–358