The Mystery of the Brachialis Muscle Revealed (QUARANTINE RISK)

Hooper’s Beta Ep. 40

Intro

Brachialis! The workhorse elbow flexor that literally is overshadowed by the biceps brachii. In this episode, we take a look at the brachialis, the prime elbow flexor of the arm. A muscle that has been misunderstood over the years, to the point where, even recently, text books will have inconsistent writings of origins, insertions, and even the fact that there are 2 muscular heads! So, stay with us fellow anatomy, rehab, and most importantly, climbing fans, as we look at the function, signs and symptoms of injury, testing, and rehab of the all important brachialis muscle (BM). 

Side note,  I want to explain that in general, brachialis injuries are quite uncommon. In fact, nearly every article I read (and reference in the show notes) starts something like “injury to the brachialis muscle is a rare injury”.. So, as you can imagine, there isn’t a ton of available published research regarding the brachialis and climbing injuries. BUT, we know that climbing places stress on the elbow flexors unlike many other sports, so we need to take the literature that is out there, utilize the knowledge we have of anatomy, and develop a deeper understanding of this workhorse. 

Anatomy

The brachialis muscle (BM) has a superficial head (SH) and deep head (DH). The deep head, based on it’s mechanics, is best for helping initiating elbow flexion when the arm is in full extension. It also will continue to assist the arm through further flexion. (3, 5, 6). The SH helps in stabilizing the arm during mid flexion (5, 6) and really has its greatest mechanical advantage “when the arm is at 90 degrees flexion” (3). Together, the two muscles provide a sort of sling, which can provide a form of rotatory torque on the proximal part of the ulnar. This makes it well positioned to dynamically stabilize the forearm against rotation. In other words, it can help lock the elbow when it is threatened with rotatory instability (5). 

So, what the heck does this all mean for climbing?!

Well, duh, a lot. It initiates elbow flexion, it sustains mid flexion, and it stabilizes against rotation (see: barn dooring). SO, I’ll let you take a moment and use your imagination on how it can help us with climbing. 

OK, OK, I get it, it is helpful for climbing, why does it matter? Well, now, with more people being introduced to hangboard programs and doing home training (quarantine 2020), we may be doing more pull up variations, more lock off training, and we may set ourselves up for a new injury. So, let’s look at some of the common risk factors and mechanisms of injury.

Climbing and Training Mistakes

So, let’s look at some climbing and training mistakes that can be made that may cause this injury. 

1. Not properly engaging your back while doing back exercises, which in turn, makes it an arm exercise. 

   • Share the load! Keep your back engaged with pull-ups and other exercises that are not just meant to be an arm exercise. 

2. Too many attempts at a lock off position

   • I’ve said this before, but you need to be careful when projecting. Too many attempts at a really hard project can set you up for injury. Understand your body and how it can handle those forces and try to limit your number of attempts. 

3. Pull up variations with sustained elbow flexion. Remember, the brachialis is “responsible for sustaining the forearm in flexed positions” (5). 

   • An example of this would be Frenchie pull ups

     1. Now that doesn’t mean they are bad! Just remember, appropriate load management. Frenchie pull-ups shouldn’t be the only form that you do nor should you be doing them every day. But once, twice a week? Totally manageable!

4.  Not controlling the end and beginning of a pull up (remember, the Brachialis is the main initiator of the movement at the elbow. Don’t just use your arms! Initiate the movement by pulling with your back AND arms. 

5. High volume of underclings and possibly sidepulls

   • This would be more of a concern if you are combining a lot of the other factors, like doing high volume underclings then deciding it’s a great idea to go do a bunch of lock offs on the pull-up bar. 

6. Making every day bicep day (overuse) 

   • There is literally a case report of a young athlete performing bicep curls and pull ups 6 days a week developed myositis ossificans of the brachialis due to this intense overuse. (4)

The most important note I can say about all of this, is load management. The body can do all of these things! It is the frequency and intensity, and volume you do that really matters. Those factors are all modifiable, especially if you write things down. Writing down your training allows you to track it so you know if you have done enough, or too much. And always, allow for rest and recovery to make sure you are completely recovered from your training before you go at it again. 

Mechanisms of Injury

Are there any traumatic mechanisms of injury?  

Well, if we are looking at a traumatic injury, it is most likely a fall or forced hyperextension of the elbow (1, 2, 3, 6). The brachialis is likely trying to resist this hyperextension and if there is too much force, it will cause failure and injury. 

Symptoms

Finally, we can talk about symptoms. 

Now, this is important. Most patients do not report feeling a pop at the time of injury (1, 2) so don’t rely on that. Most symptoms, rather, will be related to pain or soreness over the anterior mid portion of your arm to the medial aspect of the elbow (1, 3, 6) 

IF you have a partial tear, it has been shown that the “The point of maximum tenderness was over the anterolateral aspect of lower right arm” (6).  Complete tear, has also been shown to have the most  “pain and swelling at the lateral side of her distal right forearm” (2)

Unfortunately, the presentation of a true brachialis injury is often similar to that of a tear to the distal biceps tendon (1). 

So, clearly the symptoms are not a great give away, you don’t have any true gold signs that you have this, there is nothing that easily differentiates it from other injuries. WIth that being said, if you can help rule out the likelihood of another injury, your chance of accurately diagnosing your injury increased. 

Differentiating From Other Injuries

BM function is not dependent on forearm position. This means you can differentiate this from the LHB with supination. In fact, it has been shown with EMG studies that the biceps brachii and brachialis CAN be differentiated with flexion and supination (8).   So, try to pay close attention to your testing. If you have more pain with elbow flexion in neutral, and pronated, than you do in supination, you may use this to help decide if you have a biceps brachii or brachialis muscle injury. 

Now, we also need to differentiate this from medial epicondylitis stemming from the wrist flexors. To do this, you will need to test resisted wrist flexion and resisted elbow flexion and see which causes discomfort. If you have no pain with wrist flexion in any position but rather elbow flexion produces the pain, you have just reduced the likelihood it is a wrist flexor issue and again, made your diagnosis more accurate. 

Well, can I push on it and produce the pain? This can be difficult because the muscle is deep to the biceps, but as we know from reviewing the anatomy, it will be palpable from the mid humerus to the medial elbow. It can be felt on the lateral side going off of the deltoid insertion, or from the medial side going between the space of the biceps and triceps. If your injury isn’t to this specific site, although, you won’t likely cause too much pain to this area. 

Ultimately, if you are uncertain, seek out professional help and see if they can further assist you in accurately identifying your symptoms!

Treatment

Treatment of this issue really focuses on proper tissue loading. Remember, the body not only wants to heal, but it doesn’t want to be in pain! A lot of our issues are due to overloading the tissue, or not working up to moving smartly. 

1. Review the volume you are putting on the elbow flexors, review how much training you are doing and if you are actually engaging your back during back exercises, or if you are just pulling with your arms. 

2. Review your style of climbing, do you do a lot of cave with undercings then go and train a lot of lock offs? 

3. Most of these issues with good range of motion and safe loading will heal up. It was shown that a tear of this healed and full abilities restored in 3 months (4) 

If you have an injury or a tear, you may need to rest initially before starting rehab.I know, rest is boring advice, but the good news is that conservative case reports will show full return to function and prior level with rest and proper rehab (1) 

Well, can I massage the issue away? Deep tissue work. As we mentioned before, since it is deep to other structures, this is hard to accomplish, BUT, try to use a tennis or lacrosse ball or even a foam roller. If you feel like you are producing good tissue mobilization to the area, then you are successful and you may be able to assist your healing process with a bit of tissue mobilization. 

Finally, let’s talk about exercise. 

If you have a minor issue, have reviewed your training style, you may need to do some eccentrics.  “Kulig et al showed that the brachialis muscle is preferentially recruited over the biceps brachii when undergoing eccentric contraction” (3). So, do eccentrics in supination, neutral, and pronated. Heal that muscle! If you don’t understand why you should be doing eccentrics, please follow the link to our video about why eccentrics are helpful! https://youtu.be/Ehxbtz7O0p0.

Of course, if after reading this you discover that the issue is doing too much, you need to subtract something if you are going to do eccentrics, because again… load management. 

Cross training: muscle imbalances can also cause issues! Increase your tricep strengthening to help balance your body! This is a time when push up training can be helpful, or work on your climbing core and do more planks. See our core progression for ideas on how to perform awesome planks while increasing the upper extremity push muscles and improve stability!

Level 1: https://youtu.be/PEG1rX7l2vQ

Level 2: https://youtu.be/sZMQpO1xMew

Level 3: https://youtu.be/oJ5Ln-q4_2M

Closing

Remember, the body wants to heal, the best we can do is provide it the tools to do so and understand our limits. Write things down, track your training, and you will find success!

Train. Climb. Send. Repeat

References

1. Curry, Emily J., et al. “Brachialis Muscle Tendon Rupture of the Distal Ulnar Attachment in a Competitive Weight Lifter.” Orthopedics, vol. 42, no. 3, 2019, doi:10.3928/01477447-20190221-04.

2. Forsythe, Charlie M., et al. “Acute Brachialis Muscle Tear in a Pediatric Patient.” Radiology Case Reports, vol. 15, no. 5, 2020, pp. 498–501., doi:10.1016/j.radcr.2020.01.041.

3. Galanis, Nikiforos, et al. “Unsupervised Exercise–Induced Myositis Ossificans in the Brachialis Muscle of a Young Healthy Male: A Case Report.” Orthopaedic Journal of Sports Medicine, vol. 5, no. 7, 2017, p. 232596711771878., doi:10.1177/2325967117718780.

4. Ilayperuma, Isurani, et al. “Re-Visiting the Brachialis Muscle: Morphology, Morphometry, Gender Diversity, and Innervation.” Surgical and Radiologic Anatomy, vol. 41, no. 4, 2019, pp. 393–400., doi:10.1007/s00276-019-02182-2.

5. Leonello, Domenic T., et al. “Brachialis Muscle Anatomy.” The Journal of Bone & Joint Surgery, vol. 89, no. 6, 2007, pp. 1293–1297., doi:10.2106/jbjs.f.00343.

6. Sharma, Pankaj, et al. “Isolated Traumatic Brachialis Muscle Tear: A Case Report and Review of Literature.” Bulletin of Emergency and Trauma, vol. 5, no. 4, 2017, pp. 307–310., doi:10.18869/acadpub.beat.5.4.476.

7. Staudenmann, Didier, and Wolfgang Taube. “Brachialis Muscle Activity Can Be Assessed with Surface Electromyography.” Journal of Electromyography and Kinesiology, vol. 25, no. 2, 2015, pp. 199–204., doi:10.1016/j.jelekin.2014.11.003.

8. Winblad, James Bret, et al. “Brachialis Muscle Rupture and Hematoma.” Radiology Case Reports, vol. 3, no. 4, 2008, p. 251., doi:10.2484/rcr.v3i4.251.

Disclaimer:

As always, exercises are to be performed assuming your own risk and should not be done if you feel you are at risk for injury. See a medical professional if you have concerns before starting new exercises.

Written and Presented by Jason Hooper, PT, DPT, OCS, CAFS

IG: @hoopersbetaofficial

Filming and Editing by Emile Modesitt

www.emilemodesitt.com

IG: @emile166