Table of Contents
On shrugs, muscles worked primarily include the traps but one buff doctor (Dr. Mike Israetel PhD.) says to never do shrug workouts.7 Or more so, many people don’t need to incorporate shrug work since they’re hit adequately with side delt work.
To understand why the body mechanistically works this way, we’ll discuss the different muscle groups that shrugs do work, including synergistic muscles and stabilizing muscles, variations of the shrug and their various benefits, offer a few shrugging routines for those who really want to zone in on neck and trap hypertrophy.
Additionally, we’ll also deep dive into why an exercise regimen that includes side delt work may offer more than enough stimulus to maintain and even grow the traps.
What Do Shoulder Shrugs Work? (Shrugs Muscles Worked)
Interestingly enough, there has not been a specific study performed to directly look at the shoulder shrugs muscles worked. This is notable since most other muscle groups in the body have had papers published discussing the muscles worked.
Think about the bench press muscles worked or the close grip lat pulldown muscles worked — both of these exercises have been well-researched to see what muscles are primary movers and which are secondary.
Regardless, based on the human anatomy, understanding the major shrugs muscles worked is quite simple.
Posterior Shoulders (but Only to an Extent)
There is some disinformation out there in other articles that discuss shrugs’ muscles worked saying that the shoulders are an important mover in the shoulder shrug, but this is simply false. There is no real evidence to suggest that the shoulder shrug is a good exercise to perform for shoulder growth.
The only part of the shoulder complex that is affected during a shoulder shrug is the rear delt, which, functionally, is used to keep the shoulders from rounding forward. Proper shoulder shrug form ensures that the shoulders are locked back and down, which will activate the rear delt slightly.
Even still, it is not taken through a large range of motion, so for those aiming to out-train bad shoulder genetics through incorporating shrugs, looking instead to compound shoulder exercises makes the most sense.
Neck and Erector Spinae (As Stabilizer Muscles)
There are 26 separate muscles in the neck in total, but all that needs to be known when it comes to shoulder shrugs is that they can be split up into posterior, middle, and anterior neck muscles.1
What this means is that the neck is trained by doing movements that train in three different ranges of motion — posterior, by craning the neck up toward the ceiling, middle, by laterally tilting the head side to side, and anterior, by bringing the chin towards the chest.
When it comes to the shoulder shrugs’ muscles worked, the neck is not taken through any of these ranges of motion. But, the neck muscles must be flexed and held tight to prevent the head from rolling around and causing unnecessary flexion.
If the neck were not flexed during a shoulder shrug, a lifter could injure themselves.
The erector spinae muscles, similar to the neck, are not taken through a full range of motion during a shoulder shrug.2 The erector spinae runs along the spine, all the way from the tailbone up to underneath the upper traps, and has two main functions — to laterally flex the spine side to side and to extend the spine straight up.
Neither of these functions is trained when performing a shoulder shrug, so while the spine needs to be stabilized throughout the movement, it is not taken through a range of motion.
For someone whose goal is to develop stronger erector spinae muscles, consider performing a traditional deadlift — a 2020 systematic review of the literature on deadlifts has shown that this will activate the erector spinae best when compared to any other deadlift variation.3
This is important to note because, like the shoulders, some articles online mention that the erector spinae muscles are significantly trained when performing shrugs, but that is simply not the case.
Trapezius or Traps (the Primary Shrugs Muscles Worked)
When it comes to what muscles does shrugs work, the trapezius muscles need to be discussed heavily.
The traps are made up of three separate parts — the upper traps, the middle traps, and the lower traps, and each part has its own main function.
The upper traps, the largest portion of the overall trapezius muscle, function to rotate and lift the shoulder blades upward, which occurs during a shoulder shrug.
The middle traps, on the other hand, help with retracting the scapula or pulling the shoulder blades together. Lastly, the lower traps do the opposite of the upper traps — they help the shoulder blades to rotate downward.
So, what does all of this mean for the shrugs muscles worked? Well, since the upper traps are the only part of the traps that function to pull the shoulders up, the shoulder shrug should, in theory, only really activate that part of the trapezius muscle.
According to one paper that compared 10 different shoulder exercises, the unilateral shoulder shrug does fall in line with this logic.4
The unilateral shoulder shrug was far and away the best exercise for activating the upper traps, but as the EMG data was looked at further down the back, there is a clear trend that the shrug is less and less effective. Meaning, the middle traps had about half of the activation of the upper traps during the shrug, and the lower traps had half of that.
What this means is for a lifter considering adding shoulder shrugs into their routine, it should be added solely if a person is unhappy with their upper trap growth, the muscles feeding into the back of the neck. Otherwise, it is simply ineffective for growing the mid or lower traps.
Minor Muscles Worked During the Shrug
Like other exercises that require a lifter to hold a dumbbell or barbell, shoulder shrugs require the use of a few synergist muscles and tertiary muscles to assist throughout the movement.
Source: Hank Grebe via Canva.com8
The main synergist muscle that is worked is known as the levator scapulae, a muscle that runs in line with the neck musculature that, as their name implies, serves to assist the scapulae.5 Primarily, it assists to raise the scapular plane, meaning it assists when the arms are raised out to the sides.
On the side of tertiary muscles, there are quite a few groups of muscles that are technically ‘worked’ when performing shrugs, but are not effectively taken through a full range of motion. This is why we consider them to be tertiary muscles rather than secondary.
These muscles include:
- Finger extensors
- Forearm extensors
- Forearm flexors
- Calves, quads, hip flexors, glutes, and hamstrings (to help stabilize the lower body)
What Shrug Variations Is Best? Wide, Narrow, & Snatch Grip Shrugs vs Barbell, Dumbbell, Kettlebell, & Smith Machine Shrugs
While there is no present research available that can give us a definitive answer on which shrug variation is best, we can discuss shoulder shrug variations and how they may affect a lifter differently.
Any form of barbell shrug — wide grip, narrow grip, or snatch grip — has the greatest capacity for progressively overloading the movement. Since the lifter only has to grip the single barbell and doesn’t need to unilaterally stabilize the movement, they can load up more weight than possible when performing a dumbbell shrug.
That being said, using a barbell to shrug limits the range of motion that can be performed when shrugging.
Proper shrug form requires the lifter to be standing straight up with their shoulders locked back and down, lightly activating the rear delts, and contracting with the upper traps to pull their shoulders up towards their ears, holding for a second, then lowering them back down in a controlled way.
When using a barbell, it is difficult to completely retract the scapula and activate the rear delts, meaning a bit of potential activation is being missed out on. Arguably, this means that performing unilateral dumbbell shrugs or even bilateral dumbbell shrugs is best for getting the optimal contraction, and this is likely the case.
The range of motion when using dumbbells or kettlebells is slightly greater than the one available when using a barbell, but as we said, if the goal is loading the traps as heavily as possible, using a barbell is the way to go.
How To Do Shrugs Safely To Avoid Injury
The buff doctor mentioned in the title of this article is Mike Israetel, cofounder of Renaissance Periodization, a YouTube channel dedicated to providing quality, well-researched content about weightlifting.
He has multiple videos discussing the efficacy of shrugs, but also ones that elaborate on the best ways to perform them safely and for optimal growth.
One idea he brings up is to perform shrugs with lower weights, maximum stretch, little rest, and higher repetitions. The idea is that the upper traps prefer a high amount of repetitions when the target is hypertrophy, and because the traps are a smaller muscle group, they can take quite a bit of work in one sitting while recovering quickly.
He recommends performing a set of 15-30 shrugs with a large stretch at the bottom, a 1-second squeeze at the top, and 15-30 seconds of rest in between sets to get as much juice as possible out of the traps.
On the side of safety, there are not that many things to keep in mind other than control. Many people roll their shoulders when performing shrugs, but this is simply ineffective for targeting the traps.
Think of it as similar to the optimal bench press bar path since many people use the wrong bench press path. For the shrugs, the weight should simply move straight up and down, whereas when someone rolls their shoulders, the weight is moving forward and backward needlessly.
A person should perform a shrug as mentioned above — lock the rear scapula into place by tightening the rear delts and shrug the weight up toward the ears, controlling the eccentric on the way back down.
This is a crucial point — without properly controlling the eccentric, a person who is lifting too heavy of weight could injure themselves. Further, this can make it difficult to achieve a strong mind-muscle connection between the brain and the traps, which can hurt the potential for hypertrophy overall.
Shoulder Shrug Benefits
Other than for growing what many people see as a vanity muscle (the traps), the shoulder shrug has a litany of benefits for the back.
Quick Trap Growth
This is the main reason why many people want to train using shoulder shrugs — it can help the traps to grow up, providing the appearance of an overall bigger neck and upper back. In most cases, when people begin to isolate their traps and train them regularly, they do get larger quite easily; they just take some extra volume to do so.
Better Scapular Retraction (= Better Posture)
Arguably, when it comes to the overall biggest benefit of the shoulder shrug, building up better posture is likely the winner.
As mentioned a few times already, a proper shoulder shrug is performed with a retracted scapula and flexed rear delts. Training the body to lift heavier and heavier weights while keeping the scapula fixed in this position will train it to be retracted by default, which will significantly contribute to an improvement in posture.
In the modern day, a significant portion of the population works out of an office space which necessitates them to be looking down at a computer screen at all times, leading to their shoulders rounding forward, their neck craning down slightly, and their upper back subsequently collapsing.
Shoulder shrugs can help negate this by training the muscles that prevent the upper back from rounding — the rear delts and the traps.
Another exercise that can be highly beneficial for people looking to improve their posture is the humble row since it also targets scapular retraction.
Stronger Shoulder and Back Stabilizers
This should be a given considering the shoulder and back stabilizers, like the lower traps and erector spinae, are secondary movers when it comes to the shrugs’ muscles worked, but performing shrugs regularly is key to getting stronger in these muscle groups, which will simultaneously have some carryover into other lifts that require scapular retraction or spinal flexion.
However, keep in mind that these groups are not taken through a significant range of motion when performing a shrug, so don’t expect them to be trained to a significant extent as compared to exercises that would take them through a full range of motion, like the deadlift for the spinal erectors or the overhead plate raise for the lower traps.
Why Barbell Shrugs and Dumbbell Shrugs May Not Be Necessary for Most Gym Goers
At this point, we should have a solid foundational understanding of what muscles the shrugs train. Still, specifically for the traps, we should understand that scapular retraction and moving the shoulders up and down is their main function.
The thing is, virtually any sort of back or shoulder movement has one of these elements in place.
Think of the deadlift. Locking out at the top of a deadlift involves the shoulders being rolled back and down, and the scapula retracted.
Or the barbell row, where scapular retraction is the main objective when performing the movement. Or the lateral raise, where the elbows are raised to the sides, with the shoulder joint slightly moving up and down to assist throughout the motion.
The point is: the traps typically get more than enough training from non-isolation work that isolation work, like the shoulder shrug, is not necessary for trap growth.
This is true for virtually all lifters but those who want to grow really huge traps; shoulder and back exercises typically give enough stimulus to the traps to maintain or even slightly grow them.
This means that for beginners especially, direct trap training (like shrugs) is probably unnecessary for growth.
Mike Israetel has directly discussed the proper amount of volume required for trap growth in both video and blog form. The maintenance volume (MV), or the amount of volume required to maintain size, is 0 sets per week, assuming the lifter is performing compound pulling movements and potentially heavy deadlifts.
What Israetel calls the MEV, minimum effective volume, is the amount of volume required to stimulate any sort of gains. For the traps, he advises that 4 sets of trap work per week are more than enough to elicit some form of trap gains, which is pretty inconceivable when compared to a more difficult muscle to grow like the calves.
Even still, he mentions that simply upping the volume of pulling movements performed per week should be enough stimulus to get some trap gains without adding isolation work.
Adding movements where the arm abducts to the side, like the internally-rotated lateral raise, has been shown to significantly stimulate the traps, as well, suggesting combining lat raises with compound pulling movements may be more than enough to make gains.6
Last but not least, for ‘optimal’ trap training, the maximum adaptive volume (MAV) for the traps is somewhere between 4 and 12 sets of training per week.
In terms of what has already been discussed, this may mean adding 2 days of trap work with 3-4 sets on each day, or more based on if the goal is to blow the traps up or to simply make steady gains.
Sample Shoulder Shrug Workouts (for Those Who Want Huge Traps)
For those who want to perform more volume, leaning into their MAV, performing a shoulder shrug workout once or twice a week can be great for optimizing trap or neck growth, or even help to develop greater shoulder mobility.
Based on Dr. Mike Israetel’s recommendations, each of these workouts maxes out at 4 sets of direct trap work — perform a mixture of the workouts throughout the week to target different parts of the body, but doing even one of the workout routines for a week should be enough volume to get some trap gains.
Shoulder Shrug Workout #1 (Upper Traps-Focused)
Unlike the other two workouts, there is an emphasis on targeting optimal trap growth by reaching the 4-set recommendation per Dr. Israetel.
For the upper traps, in particular, performing variations of the shrug using different loading schemes (barbell, dumbbell, machine) is a fantastic way to hit parts of the traps that were missed.
Compared to the other two workouts, the volume for this one is a bit lower because it should be performed multiple times per week since upper trap work isolates the muscles a bit more and can recover marginally more quickly than the mid or lower traps.
Barbell shrugs: 2×10-15 reps, 2-3 minutes rest in between each set; the goal here is to target strength adaptations in the traps
Dumbbell shrugs: 2×15-30 reps, 15-30 seconds rest in between each set; the opposite of the barbell shrugs, the goal here is to target hypertrophy and burning out the traps.
Shoulder Shrug Workout #2 (Shoulder Mobility-Focused)
This is more of a combination of some shoulder shrugs with some mobility work to help those who have poor shoulder mobility.
Dead hangs: 3×10-60 seconds, 2-3 minutes rest in between each set; hang from a bar and let the shoulders shrug up to the ears to stretch the delts.
Prone bent arm chest stretch: 3×10-60 seconds, 2-3 minutes rest in between each set; lay with belly on the ground and arms straight out to both sides, and choose one arm to place flat on the ground and push up to stretch the opposite shoulder. Reverse, and repeat 3 times to target stretching the inner part of the shoulder.
Dumbbell shrugs: 3×15-30 reps, 15-30 seconds rest in between each set; since this is the only strength-targeted portion of this routine, ensure each rep has a deep stretch at the bottom and a hard contraction at the top.
Shoulder Shrug Workout #3 (Lower Traps-Focused)
Last but not least, let’s take a look at the best ways we can train the lower traps. As discussed above, while the upper traps mainly grow via stimulus in the vertical plane, where the shoulders are vertically shrugged, the lower traps tend to grow best via scapular retraction and protraction.
This means that for optimal lower trap training, targeting compound pulling movements where the scapula retracts, like the bent-over row and the cable row, as well as isolation movements like the face pull will be best.
Cable row or bent-over row: 3×12-15 reps, 2-3 minutes rest in between each set; perform either of these exercises based on how fatigued the lower back feels on a specific day, using the cable row when it is more fatigued. Ensure to get a massive range of motion with each rep, protracting the scapula at the bottom of the movement and retracting it fully at the top
Face pull: 3×15-20 reps, 1-2 minutes rest in between each set; the goal here is not necessarily to have perfect form with every rep, but to rip the weight back with force to fully retract the scapula, then control the eccentric until fully protracted.
Dumbbell shrugs: 2×15-30 reps, 15-30 seconds rest in between each set; as per usual, with any shrugs workout, there have to be shrugs. Focus on having a solid contraction at the top of each movement and controlling the eccentric.
Shoulder Shrug Workout #4 (Neck Muscles-Focused)
Last but not least, a neck-focused shrug workout. Most people don’t know how to actually train their neck, and proper neck training necessitates research to understand the dangers that come along with it.
Regardless, this routine focuses on neck hypertrophy above all else — ensure to ramp the weight up slowly to stay safe, as the neck is quite a sensitive area of the body.
Neck curl: 2×10-20 reps, 2-3 minutes rest in between each set; lay flat on a bench with the head dangling over the edge, and place a plate (yes, a plate) on the forehead, curling the neck up, and controlling the descent back down.
Neck extension: 2×10-20 reps, 2-3 minutes rest in between each set; similar to the neck curl, but lay with the chest on the bench rather than the back and perform a similar head motion.
Dumbbell shrugs: 2×15-30 reps, 15-30 seconds rest in between each set; a bit lower volume for shrugs since, by default, the traps will be slightly activated during the above neck exercises.
Considering the shrugs’ muscles worked are primarily the upper traps, but the upper traps receive more than enough stimulus from compound pulling movements for growth, performing shrugs may not even be necessary to grow the traps at a decent pace.
Frequently Asked Questions
How Many Reps of Shrugs Should I Do in a Set?
According to Dr. Mike Israetel, performing shrugs with sets of 15-30 repetitions is optimal for hypertrophy. He argues that they are similar muscles to the biceps or calves, meaning they require a high amount of repetition and can handle it quite easily.
How Often Should I Do Shrugs & Hit Traps?
As aforementioned, to grow the shrugs, performing any sort of compound pulling movements should help the traps grow. But, if a person wants to maximize trap growth, performing 4 sets of shrugs one or two times per week would help the traps grow optimally.
Are Traps Good for Strength Athletes?
Yes, having well-developed traps is advantageous for athletes. This is because large traps will almost by default mean that they have a strong scapula and good posture which is highly beneficial for any sport and life in general.
Should Bodybuilders Do Shrugs for Size & Hypertrophy?
For those who are trying to build the largest traps possible, performing traps shrugs, shrugs that solely focus on the traps, is a good idea. Some extra volume on top of compound exercises will optimize training for growth and strength, but as already said multiple times, it may not be necessary for the average lifter.
Are Shoulder Rolls Safe and/or Effective?
Shoulder rolls are certainly safe to perform, but they are ineffective for hypertrophy or even strength. This is because they don’t load the traps or neck muscles, so the potential for hypertrophy or strength increases is minimal.
Are Shrugs Good To Get a Big Neck?
Performed properly, shrugs can certainly help a lifter get a thick neck. As long as the shrugs are performed with proper form, the neck will be contracted tightly throughout the range of motion, which will give the neck musculature a decent amount of stimulus.
References
1Contributors to Wikimedia projects. (2022, December 17). Neck. Wikipedia. <https://en.wikipedia.org/wiki/Neck>
2Contributors to Wikimedia projects. (2022, August 24). Erector spinae muscles. Wikipedia. <https://en.wikipedia.org/wiki/Erector_spinae_muscles>
3Martín-Fuentes, I., Oliva-Lozano, J. M., & Muyor, J. M. (2020). Electromyographic activity in deadlift exercise and its variants. A systematic review. PloS One, 15(2), e0229507. <https://doi.org/10.1371/journal.pone.0229507>
4Ekstrom, R. A., Donatelli, R. A., & Soderberg, G. L. (2003). Surface electromyographic analysis of exercises for the trapezius and serratus anterior muscles – PubMed. The Journal of Orthopaedic and Sports Physical Therapy, 33(5). <https://doi.org/10.2519/jospt.2003.33.5.247>
5Contributors to Wikimedia projects. (2023, January 12). Levator scapulae muscle. Wikipedia. <https://en.wikipedia.org/wiki/Levator_scapulae_muscle>
6Coratella, G., Tornatore, G., Longo, S., Esposito, F., & Cè, E. (2020). An electromyographic analysis of lateral raise variations and frontal raise in competitive bodybuilders. International Journal of Environmental Research and Public Health, 17(17), 6015. <https://doi.org/10.3390/ijerph17176015>
7ruigsantos. Canva. Accessed 20 April 2023. <https://www.canva.com/photos/MAC_6Z7h5Z8-dumbbell-shrugs/>
8Grebe, Hank. Canva, 29 July 2022. Accessed 20 April 2023. <https://www.canva.com/photos/MAD9YMqg3_M-male-levator-scapulae-back-muscles-in-isolation-on-skeleton/>