Chin-ups are a challenging bodyweight exercise, but they are worth incorporating because they work a ton of muscles at once, and have different variations that you can use to bring up lagging muscle groups.
Chin-ups primarily work the back and biceps due to the underhand grip taken while hanging on the bar. Once you master the chin-up, you can add in chin-up variations that will help you expand your workouts by shifting more or less emphasis to other muscle groups to help you grow more muscle.
Understanding what muscles should be working in a chin-up can be challenging, especially if you aren’t fully sure what a chin-up is or how to tweak them to target some muscle groups more than others.
With this article, you will learn everything you need to know about chin-ups and chin-up variations, and more importantly understand which variation you should be incorporating.
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What Is a Chin-Up?
A chin-up is a movement in which you hang from a bar with an underhand grip, and pull yourself up using your biceps and back muscles.
This exercise is NOT the same as a pull-up, despite many individuals labeling them incorrectly or interchangeably.
A chin-up differs from a pull-up in that the grip on the bar is different (chin-ups use an underhand grip, whereas pull-ups use an overhand grip). By changing the grip, you can shift more emphasis to the biceps (as in the chin-up) or the back (as in the pull-up).
Muscles Worked In Chin-Ups
Below is a comprehensive list of the primary and secondary muscle groups used while performing chin-ups.
Biceps Brachii (Biceps)
The biceps are located on the arm, and when they contract (a muscle contraction is when a muscle is shortening or “flexing”) they bend the elbows.
During a chin-up, the biceps are targeted more due to the underhand (pronated) grip taken on the bar, which places more emphasis on the biceps as they bend the elbows (unlike a pull-up, which uses less biceps) to pull you up.
Related Article: Best Bulking Arm Exercises
Latissimus Dorsi (Middle and Upper Back)
The back muscles are another muscle group used during a chin-up, which works with the biceps and other muscle groups to help pull you up.
The lats span across the entire upper and middle back and are responsible for pulling the arms down to the sides from an overhead position. During a chin-up, the lats works with the biceps as prime movers; however, the lats are less involved in the chin-up than they are in the pull-up due to the biceps taking on more of the workload (due to the underhand grip).
The traps are a large muscle group that run the entire length of the back (vertically). Most people know of the upper traps, which are visible on the upper back and are responsible for shrugging the shoulders, but many are not aware of the middle and lower trap muscles. The middle and lower traps aid in shoulder stabilization and postural support.
During the chin-up, the traps are a key muscle group for providing shoulder and postural support. They also help assist the lats by keeping the body erect rather than hunched forward.
Erector Spinae (Lower Back)
The erectors are the muscles of the lower back and are responsible for keeping an upright torso. When the erector muscles contract, they straighten the spine and help ensure the lower back is not rounding excessively (which could cause injury).
During the chin-up, the erectors are working constantly to help ensure that your lower back is supported during the lift. It also helps the traps with proper posture and stabilization of the body while hanging under the bar.
The rhomboids (major and minor muscles) are located around the shoulder blades (in between them). These small but mighty muscle groups are responsible for stabilizing the scapula (shoulder blades) and ensuring proper joint function at the shoulder during the chin-up.
During a chin-up, the rhomboids assist the lats by pulling the shoulder blades down and back during the lift.
The teres major is a small muscle group that is around the shoulder blade. This small, yet important muscle is responsible for stabilizing the shoulder blades and helps to maintain shoulder range of motion.
During a chin-up, the teres major assist the rhomboids and traps in supporting the shoulder blades while you produce high amounts of muscular tension (force) from the lats and biceps.
Without shoulder stability, your chin-ups won’t feel as smooth as the muscles won’t be working synergistically, and you will also be more susceptible to shoulder injury.
The abdominal muscles are responsible for bending the torso, rotation, and resisting external forces that may twist or bend the spine in harmful ways. When we train the abs, we are building up the muscle’s ability to not only promote movement but also withstand external forces that may place us in a harmful position.
During the chin-up, the abdominals are working in an isometric state (the muscle is contracting, but it is not producing movement, rather it is resisting movement). To visualize this, think of how your abs work in a plank (isometric) versus a sit-up (dynamic).
By keeping the abdominals engaged in a chin-up, you help stabilize yourself in space as you hang from the barbell. This increased stability will allow your lats, biceps, and traps to do their jobs properly to lift you up.
Related Article: 3 Best Workouts on a Pull-Up Bar
The forearms are a group of smaller muscles that are responsible for opening and closing the fingers, flexing and extending the wrists, and aiding in your ability to grab, grip, rip, and hold onto things.
During chin-ups, you are working your forearms in a couple of ways. Your forearm muscles work to grip the bar and assist the biceps by helping to bend the elbows as you perform the chin-up.
If your grip strength is weak then you may notice that your forearms get tired faster than your biceps or lats.
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Muscles Worked in Different Chin-Up Variations
There are a number of chin-up variations that you can include in your training plan to emphasize certain muscle groups over others or to increase the level of difficulty of the movement.
Note: Not all of these variations can be found in the Fitbod app.
The assisted chin-up works all of the same muscles as the regular chin-up, just to a lesser degree as you do not need to lift your entire bodyweight.
To perform the assisted chin-up, you will need either an assisted chin-up machine or a loop band. Both of these are good options to help you master the correct technique with less weight to build your chin-up strength.
I recommend giving yourself enough assistance to be able to perform at least 5 chin-ups. If you can’t do 5 solid chin-ups, then increase the weight on the machine or choose a heavier band.
The Australian chin-up is a chin-up variation that targets the same muscle groups as a chin-up, just to a lesser degree.
This exercise is a regression of the chin-up that is ideal for lifters who cannot perform chin-ups or those who want to do higher rep sets to work their lats and biceps but don’t have the grip strength or endurance to do so in the regular chin-up.
To perform an Australian chin-up, set yourself up as you would in the inverted row (holding onto a bar in a rack or rings with your arms straight and your body in a plank position). Take an underhand grip and pull yourself to the bar or rings (feet stay on the ground) at an angle.
The eccentric chin-up is a chin-up variation that places 100% of the emphasis on the lowering phase of the chin-up (eccentric phase), and works the same muscle groups as a chin-up but with more intensity.
Despite the increase in intensity due to increased muscle tension, eccentric chin-ups are great for beginners who want to build muscle and strength, but can’t do chin-ups yet. They are also great for stronger lifters looking to overload a muscle and get more growth, especially when done with added weight.
To perform the eccentric chin-up, you start at the top of the movement (chin over the bar, which you can get to using a bench, box, or by jumping up), and then slowly lower yourself to the bottom, and repeat.
The key here is to slowly lower yourself under control; I recommend aiming to spend at least 4 to 5 seconds lowering down.
The pause chin-up is a variation that involves pausing at various ranges of motion in the movement. Most lifters will pause at the top of the movement, at the bottom, or halfway as these tend to be the points throughout the chin-up where lifters struggle.
Where you pause will affect how much emphasis you’re putting on certain muscle groups.
For example, pausing at the top of the movement will help you target the biceps and back muscles. Pausing in the middle will place a ton of emphasis on the biceps. Pausing at the bottom will place a lot of your body weight in the lats.
Most pauses in the chin-up can last between 5-10 seconds. I recommend pausing in portions of the chin-up where you tend to struggle to strengthen the muscle groups that need additional work.
The weighted chin-up works all of the same muscle groups as the regular chin-up but increases the difficulty of the movement. By adding weight you are able to progress your chin-ups and train the muscles harder than bodyweight chin-ups.
Weighted chin-ups are key for lifters who can already perform bodyweight chin-ups and want to build more muscle and strength.
You can add weight to chin-ups by wearing a weighted vest, attaching weight to a belt, or by holding a dumbbell between your feet.
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About The Author
Mike holds a Master’s in Exercise Physiology and a Bachelor’s in Exercise Science. He’s a Certified Strength and Conditioning Specialist (CSCS), USA Weightlifting Advanced Coach, and has over 10+ years of experience working with collegiate athletes, national level lifters, and beginners alike. Mike is Founder of J2FIT Strength and Conditioning, a growing global training company with gyms in New York City, Cincinnati, and online offering personal training, online custom coaching programs.