When people think of training their arms, they usually focus on the biceps brachii and the triceps brachii - two of the largest muscle groups in the upper arm.
However, what not everyone realizes is that there is a third muscle located between these two, one that is smaller but arguably just as important in terms of appearance and arm strength.
This muscle is known as the brachialis, and is quite difficult to train without direct isolation work.
Fortunately, there are quite a number of brachialis isolation exercises, each of which are perfectly suitable for a variety of different training styles and fitness goals. In fact, it’s pretty likely that you already have one of these exercises in your training program.
The brachialis muscle is a skeletal muscle group that is located anatomically beneath the biceps brachii, wherein it contributes significantly to the mass of the arm when viewed from the side, or if the biceps are being flexed.
The brachialis is most often recruited in compound movements that involve a pronated grip, such as pull ups or close-grip cable rows.
Despite this, many lifters have underdeveloped brachialis muscles, simply because of the fact that they are unaware of this muscle group even existing in the first place.
The brachialis is responsible for elbow flexion, being the primary muscle group recruited when this particular biomechanic is initiated. It feeds into the elbow joint, with its primary attachment point (or origin) being approximately mid-way up the upper arm, just beneath the bottom of the medial deltoid head.
While this sole function is seemingly simplistic, the brachialis is the greatest contributor to elbow flexion, even in comparison to the biceps brachii.
As such, any athletes wishing to reinforce the strength of their elbow flexion would do well to train their brachialis in an isolated manner.
Directly training the brachialis muscle with targeted resistance can provide quite a number of benefits, with the most visually distinct being improved thickness of the arms, as well as significantly improved definition at the lower levels of body fat.
From a more performance-based perspective, training the brachialis reinforces the elbow flexion biomechanic, greatly improving total strength output in exercises like the pull up or row.
In particular, climbing athletes, wrestling athletes and rowing athletes will see significant benefit from the strengthening of their elbow flexion mechanic, as it is used quite frequently during their sport.
Apart from the visual and athletic benefits of training the brachialis, there is also a rehabilitative and protective benefit to doing so, as a stronger brachialis equates to a more durable elbow joint and therefore a reduced risk of injury concerning the elbow.
Not every brachialis exercise is equal, and some are more suited for certain situations than others.
For training programs without any direct brachialis recruitment, the usage of heavier brachialis exercises like the reverse curl or hammer curl are most suitable - especially when performed at the higher volumes of repetitions per set.
Otherwise, for training programs that already place a level of emphasis on the brachialis - either through compound movements like pull ups or through isolation exercise - lighter resistance movements may be more suitable.
The quintessential brachialis exercise, EZ bar reverse curls recruit the brachialis to their fullest range of motion while keeping the wrists in a position that ensures the brachialis muscles are able to exert as much force as possible.
These two mechanics combined with the impressive level of resistance that may be induced through the use of an EZ bar can result in significant muscular hypertrophy and strength developments in the brachialis.
However, EZ bar reverse curls present several disadvantages, despite their effectiveness at training the brachialis, with the most significant being the strain it places on the wrists and elbows.
Furthermore, the fact that the EZ bar reverse curl cannot be performed with one arm at a time means that it can potentially worsen any imbalances present, and even cause a muscular imbalance if careful attention is not paid to moving both arms equally.
The EZ bar reverse curl is the ideal brachialis exercise for training programs that do not recruit the brachialis, as it is heavy and effective enough to act as a stand-alone isolation movement within a workout.
Furthermore, few exercises are as effective at building brachialis mass as the EZ bar reverse curl, with its high level of resistance and isolated training stimulus being uniquely suited for inducing muscular hypertrophy.
Gripping an EZ curl bar in a pronated (palm down) grip, the exerciser will stand with their back straight and their head facing forward, ensuring that their legs are straight as well so as to avoid any swinging that may affect the exercise.
Then, pulling from the upper arms and elbows, the exerciser will curl the bar towards their chest, stopping once their forearms come into contact with their biceps.
Having completed the concentric portion of the repetition, the exerciser will then slowly reverse the motion, squeezing the musculature of their upper arm as the bar descends and stopping once it has returned to its original position.
This completes a repetition of the EZ bar reverse curl.
Lighter and more comfortable than other brachialis-focused curls, the dumbbell hammer curl also recruits other oft-forgotten muscle groups such as the brachioradialis and those of the forearms, making it essential for completing an arm day workout.
In addition to this effective spread of muscular recruitment, dumbbell hammer curls also recruit the biceps in a secondary mover capacity, only furthering the practicality of this particular exercise.
The dumbbell hammer curl is the perfect arm exercise for powerlifting programs or other compound-heavy workouts that do not place high specificity on the muscles of the arms.
Furthermore, hammer curls in general are seen as one of the most comfortable and wrist-friendly methods of training the brachialis, meaning that it is also a suitable exercise for individuals with poor arm mobility or a history of wrist stiffness.
To perform dumbbell hammer curls, the exerciser will grip a pair of dumbbells and hold them at their sides, wrists held in a neutral grip.
Then, keeping their elbows close to their torso, the exerciser will draw the dumbbells upwards - stopping just shy of the dumbbells making contact with their upper body.
Having completed the concentric portion of the repetition, the exerciser will squeeze their upper arms for a moment before proceeding to the eccentric portion of the exercise.
This is performed by simply reversing the movement, controlling the descent of the dumbbell while keeping their elbows similarly close to the torso.
Once the dumbbells have returned to their sides, the repetition has been completed.
A unique variation of curl that features both underhand and overhand grips, the dumbbell zottman curl is both an effective brachialis exercise as well as an excellent alternative to many biceps brachii isolation movements - making it a dual-purpose exercise that saves you time and energy.
Unfortunately, the dumbbell zottman curl features significant rotational pressure being placed on the wrists and forearms, and as such has a high mobility requirement in order to perform without risk of injury or improper form.
The dumbbell zottman curl is an excellent brachialis exercise for more advanced lifters seeking a movement that trains both their biceps and their brachialis muscles.
Apart from this particular case, zottman curls are also suitable for individuals that find the majority of other brachialis movements to be unsustainable due to isometric contraction, with the zottman curl featuring far less time under tension on all recruited muscle groups.
To perform the zottman curl, the exerciser will grip a pair of dumbbells in the supinated or overhand position, prior to performing an ordinary concentric bicep curl movement where the dumbbells are drawn towards the shoulders.
Then, as they do so, the wrists will rotate into an underhand or pronated grip, meaning that the eccentric portion of the repetition is performed with the palms facing downwards and away from the exerciser. The repetition is completed once the dumbbells have returned to their original position.
Due to the stress zottman curls can place on the forearms and wrists, it is vitally important to perform each repetition in a slow and mindful manner, and to avoid utilizing excessively heavy dumbbells, or those whose handle diameter are too thick to safely grip.
Simply the machine-based version of the hammer curl, cable hammer curls provide a greater time under tension and specificity of training stimulus than other brachialis exercises. These benefits are achieved through a reduction of stabilizer muscle group recruitment, and a constant level of angled resistance being applied throughout the repetition.
This greater specificity of training stimulus and adjustable angle of resistance make the cable hammer curl among one of the most compatible brachialis exercises available, providing highly targeted muscular recruitment in a manner that is comfortable for practically all exercisers.
The cable hammer curl is the ideal brachialis exercise for training programs that have no room for additional recruitment of other muscle groups, or for lifters that find other brachialis exercises to be uncomfortable or incompatible with their circumstances.
Much like their free weight counterpart, cable hammer curls are performed with the exerciser gripping the pulley handles in a neutral position, then drawing their hands upwards until their forearms come into contact with their biceps.
This is followed by the exerciser allowing the resistance of the machine to pull their hands back downwards as they squeeze their upper arms throughout the movement, completing a repetition of the exercise.
Even if you’ve never heard of the brachialis muscle before, its entirely possible that you have already been unintentionally training it through the presence of pull ups in your workout program.
Due to the pronated hand position of traditional pull ups, the brachialis is in fact recruited to a pretty significant extent, especially for exercisers that perform pull ups with a particularly close grip.
As such, in the event that you are planning to add additional brachialis training to your workout routine, we advise reducing the total volume of your brachialis isolation exercises if pull ups are already present in the same workout.
Though many bodybuilders swear by straight bar reverse curls for training the brachialis muscle, it is best to avoid this exercise altogether due to the inherent safety risks associated with its rather awkward kinetic pattern.
The shape of a straight bar - when gripped in a pronated position and curled - places excessive rotational stress and shear force on the wrists, potentially resulting in both chronic and acute injuries for individuals with poor wrist mobility.
Even lifters with perfectly adequate wrist mobility are at risk of injuring themselves with this exercise, as small breaks in form adherence or even prematurely fatigued forearm muscles can easily result in excessive stress being placed on the wrists.
Instead of performing reverse or pronated curls with a straight bar, we suggest doing so with an EZ curl bar, as the differing shape of this particular barbell will greatly reduce force placed on the wrists and forearms.
Though the brachialis muscle is seen as less important than the biceps or triceps, it is still nonetheless important to train and may even save you the risk of elbow pain in the future.
Just like training any other muscle group, make sure to follow proper training programming methods, and to ensure that your execution of any brachialis exercises is by the book in terms of form and intensity as well.
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