Chin-Ups Muscles Worked: A Detailed Guide

October 10, 2024

When performing chin ups, muscles worked include the latissimus dorsi, biceps brachii, and trapezius. Each of these performs many different functional roles.

Functional movement patterns involve exercise patterns that closely resemble those used in daily activity and exercise. We can define these as the primary movements of the human body. In total, we can define seven main functional movements — push, pull, squat, bend, lunge, and rotation.

Programming these movement types to make up the backbone of your training helps to improve everyday function and reduce injury risk when performed correctly. They help to improve determinants of performance such as muscular strength, balance, coordination, and movement efficiency.

In this article, we discuss the functional chin-up movement pattern in detail. More specifically, we look at the different stages and muscles worked for each. Let’s take a look.

What Are Chin-Ups?

Chin-ups are arguably one of the most functional bodyweight exercises you can do. Alongside the usual big three powerlifting exercises, chin-ups use a foundational movement pattern that is challenging to perform.

We can define a chin-up as a vertical pulling exercise that involves pulling your bodyweight above an overhead bar. The movement pattern is simple — hang from an overhead bar and pull your body up using your upper body and core until your chin reaches bar height.

Chin-ups are similar to pull-ups in many ways. The main difference is in the grip pattern and elbow positioning. While both movements target simple muscle groups, the relative contributions vary.

With this, the chin ups vs pull ups muscles worked will be different at each stage of the exercises. First, let’s see how to perform them.

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How To Do Chin-Ups

The chin-up can be split into three distinct stages or phases. Each stage determines the primary and secondary muscle activations. Let’s start by detailing the correct form before describing the close grip chin ups muscles worked.

Set-Up Phase

Find a suitable chin-up bar that’s above your height. This allows you to hand freely before starting the movement. It can be in a gym or park area depending on your preference.
Reach up with both arms and grasp the bar with a double underhand grip. Your hands should be around hip-width apart.
Pull your shoulder blades back and down. Bring your chest up with your head looking forward.
Inhale and engage your core. This is the correct starting position.

Pull Phase

Exhale and pull yourself up to the chin-up bar by flexing your elbows. They should be at the front of your body and stay tucked in at all times.
Keep your legs in the same position throughout or cross them over to maintain a stable body position if needed.
Pause briefly at the top position when your chin is at the height of the bar.

Lowering Phase

Gradually start to lower yourself back to the starting position under control. Allow your elbows to extend, keeping them tucked into the front of your body.
Lower until your elbows reach a fully extended position.
Repeat the same technique for the desired number of repetitions and sets.

Chin-Ups Muscles Worked

Chin-ups are generally known as an upper back exercise. Because of the arm and grip positions, the biceps brachii are more heavily involved than in a normal pull-up.

Below we’ve discussed the main muscles worked when performing the chin-up and how they contribute at each stage.

Primary Movers: Latissimus Dorsi

The latissimus dorsi muscles, or lats, are a large muscle group that spans most of the back. They primarily function to move the upper limbs and act as a respiratory accessory muscle, helping with breathing.

The primary function of the lats is to adduct and extend the arms. This means to bring the arms into and behind the body. This action is more prominent when the arms are in a flexed position, or above the head.

During the set-up phases, the shoulders flex to bring the arm to the bar. This is the starting position where the lats are most active in their two primary functions. As you perform the pull phase, the lats bring the arms into and slightly behind the body. This allows your chin to come to the height of the bar.

When performing the lowering phase, the lats lengthen to control the descent back to the starting position.

In terms of muscle activation, the latissimus dorsi muscles show an activation rate of approximately 120%. This is a measure of how hard a muscle is working against a particular stimulus.

Interestingly, lat activation when performing the pull-up was slightly higher than this. When performing wide grip chin ups, muscles worked including the lats will be slightly different.

Secondary Movers: Biceps Brachii

The biceps brachii are a muscle group located at the top of the upper arms. They can be split into two heads — the biceps short head and the biceps long head. Both heads originate from the humerus, or upper arm, and insert into the ulna, or forearm.

The principal role of both bicep heads is to perform elbow flexion. This means reducing the angle between your forearms and upper arms.

During the pull phase, the biceps brachii muscles contract to flex your elbows. This brings your body closer to the chin-up bar. The front arm and tucked elbow positions increase the activation rate of the biceps brachii compared to the pull-up movement.

With the lowering phase, the biceps brachii help to control the descent, lengthening as the elbows extend. In the same muscle activation study as above, the biceps brachii activation rate was approximately 90%-95%.

Secondary Movers: Trapezius

The trapezius muscles are a flat, superficial muscle group that extends from the upper back to between the lats. They can be divided into three muscle groups or parts. These are the upper trapezius, middle trapezius, and lower trapezius.

Each of them functions to stabilize the scapula, or shoulder blades, during arm movement. This allows you to keep the correct arm position, allowing the primary movers such as the latissimus dorsi in the chin-up, to function correctly.

The traps rotate the scapula upwards when reaching for the bar in the set-up phase. During the pull phase, they stabilize the scapula allowing the lats to function. When lowering down, the upper traps lengthen, allowing the scapula to rotate downwards.

Secondary Movers: Brachialis

The brachialis muscles are located at the front of the upper arms beneath the biceps brachii. They originate from the lower part of the upper arm and insert into the ulna, or forearm. As a primary elbow flexor, most people also consider the brachialis as part of the biceps musculature.

During the pull phase, the brachialis muscles work alongside the biceps brachii to flex the elbows. This allows you to pull up to the bar using the front elbow position. During the lowering phase, they assist the biceps to bring your body back down under control as the elbows extend.

Secondary Movers: Brachioradialis

The brachioradialis muscles make up part of the forearm musculature. They originate from the humerus and insert into the radius, or forearm. They primarily function to support elbow flexion and support forearm stabilization.

In the chin-up, the brachioradialis muscles assist the biceps brachii and brachialis to flex the elbows. This is during the pull phase as your chin comes to the bar.

Alongside this, they assist the wrist flexors and extensors to maintain a firm underhand grip. This is during all phases of the chin-up.

Secondary Movers: Wrist Flexors And Extensors

The wrist flexors and extensors are forearm muscles located on the inside and outside of the forearm, respectively. They flex and extend the fingers and the wrists, ensuring the correct positions and helping to maintain grip strength.

In the pull and lowering phases, the wrist flexors flex the fingers and wrists to grip the bar and ensure grip strength. The wrist extensors work to prevent them from overextending.

Secondary Movers: Core Musculature

The core musculature consists of the muscles that surround the trunk area. This includes the rectus abdominis, transverse abdominis, erector spinae, and obliques.

Each of them primarily functions to maintain a stable body position when still and during movement. This prevents excessive movement, helping to maintain efficient movement patterns and reduce injury risk.

When performing the chin-up, the core muscles engage to maintain a stable body position. This prevents the body from excessively moving, allowing the back and bicep muscles to function as intended.

Chinup facial expression — This facial expression isn’t necessary, but it won’t hurt

Should You Do Chin-Ups?

Whether you’re a functional fitness athlete, recreational gym goer, or committed bodybuilder, the chin-up remains a worthwhile addition to your training program. The latissimus dorsi muscles are the primary movers which means you should include them as part of a full body, back, or pull session.

With one primary mover and seven secondary movers, the chin-up is a compound exercise that should form the backbone of any well-organized training routine. Follow the form guide above for safe performance.