What Muscles Do Pull-Ups Work? (Complete Breakdown)

Ask what pull-ups work and most people say "back." EMG studies give a fuller answer: the lats and biceps are the main movers, helped by the teres major and rear delts, while the lower traps, rotator cuff, forearms, and core keep your shoulders and torso stable. Here's a muscle-by-muscle breakdown of the pull-up, what the research says about each muscle, how grip width and hand position change the work, and what's known about assisted variants.

One caveat up front: almost all of this evidence is EMG, which measures how active a muscle is, not whether it grows. We found no MRI or ultrasound study that measured muscle growth from pull-ups themselves.

Quick Answer

The pull-up trains the latissimus dorsi and biceps as the main movers, with help from the teres major, rear delts, brachialis, brachioradialis, and pectoralis major. The lower and middle traps, rotator cuff, forearms, and core work as stabilizers. In a 2010 EMG study, lat activity averaged 117–130% of maximum voluntary contraction across three pull-up styles, and biceps activity 78–96%. In that study, a chin-up grip raised biceps and chest activity and a pull-up grip raised lower-trap activity, though the studies don't all agree. Grip width doesn't clearly change lat activity, and both wide and chin-up grips carry a shoulder caution.

Pull-Up Muscles Worked at a Glance

MVIC is maximum voluntary isometric contraction, the hardest a muscle can contract in a test; MVC is the same idea. Numbers above 100% are possible in a dynamic lift. Each study tests differently, so numbers don't compare across studies, and the spread is wide: Snarr measured the lats at about 80% and the biceps at about 44%, while Li measured recreationally active men at about 93–117% for the lats and 57–67% for the biceps.

Primary Movers

These muscles pull your body up to the bar.

1. Latissimus Dorsi (Lats) and Teres Major

The lats run from your lower spine and pelvis to the front of your upper arm. They pull the arm down and back toward your side, which is the main work of a pull-up. The teres major works alongside them: Urbanczyk et al. (2020) (Scandinavian Journal of Medicine & Science in Sports), who built a computer model of the shoulder from 11 men's movements, named the lats, rear delts, and teres major as the main movers at the start of the pull.

In a 2010 EMG study by Youdas and colleagues (Journal of Strength and Conditioning Research), 25 young adults did pull-ups, chin-ups, and a version with rotating handles. Average lat activity was 117–130% of MVIC, the highest of the seven muscles reported. Dickie et al. (2017) found that activity in eight shoulder, arm, and forearm muscles was similar across supinated, pronated, neutral, and rope grips over a whole rep, with one exception covered below.

Pull-ups and lat pulldowns aren't interchangeable. In Doma et al. (2013), the chin-up produced more biceps and erector spinae activity than the lat pulldown on the way up; lat activity wasn't listed among the differences. In Johnson et al. (2009), men's one-rep max was 1.16 times body mass on the pull-up and 0.93 on the lat pulldown; women's was 0.73 and 0.55.

Loading bias: lats work hard on every variation. Neither Youdas nor Dickie found a lat difference between grips on the pull-up. On the lat pulldown, Lusk et al. (2010) found more lat activity with a pronated grip than a supinated one at both grip widths, so a pronated grip is a reasonable default, not a proven advantage.

2. Biceps Brachii

The biceps bend the elbow, and they work hard on a pull-up: 78–96% MVIC in Youdas's study, and significantly higher in the chin-up than in the pull-up.

The arm work may be enough to grow muscle, at least on a similar exercise. In one study, Gentil et al. (2015) (Asian Journal of Sports Medicine), 29 untrained men trained twice a week for 10 weeks. Lat pulldowns grew the elbow flexors by 6.1%, versus 5.8% for biceps curls, with no difference between the groups. That study used pulldowns in beginners, and a later pulldown study by Li and colleagues saw no change in upper-arm circumference, a cruder measure, so don't assume this applies to pull-ups in experienced lifters.

Loading bias: a chin-up grip is the best-supported choice, but the evidence is mixed. Youdas measured more biceps activity on the chin-up, Dickie found similar activity across grips, and Urbanczyk's computer model predicted less biceps work with a reverse grip, a conflict its authors acknowledge. For more on arm training, see Best Bicep Exercises Ranked.

3. Brachialis and Brachioradialis

The brachialis sits under the biceps, and the brachioradialis runs along the top of the forearm. Both help bend the elbow. In Dickie's study, brachioradialis activity was higher on the way up than on the way down. In Urbanczyk's model, a standard pronated pull-up favored the biceps and brachialis more than the wide or reverse grip did. That's a model estimate, and it runs against Youdas's EMG result.

Stabilizers and Secondary Movers

These muscles help with the pull, control your shoulder blades, and keep your torso steady.

4. Lower and Middle Traps

The lower traps pull your shoulder blades down, and in Youdas's study they fired early: the pull-up and chin-up started with the lower traps and pectoralis major and finished with the biceps and lats. Lower-trap activity was 45–56% MVIC and significantly higher in the pull-up than the chin-up.

The middle traps hold your shoulder blades back. Hand position does matter here: in Dickie's study, the pronated grip produced significantly more middle-trap activity than the neutral grip, with peak values of 60.1% versus 37.1% MVIC. In Snarr et al. (2017) (Journal of Human Kinetics), middle-trap activity was lower on towel pull-ups than on a standard bar.

5. Rear Delts

The rear delts help pull the upper arm back and down. They reached about 106% of maximum contraction in Snarr's study of 15 resistance-trained adults, 13 of them men, though the numbers varied widely from person to person, and about 56–58% in Li's study. Snarr found no difference in rear-delt activity between a standard pull-up, a suspension-strap pull-up, and a towel pull-up.

6. Rotator Cuff

The rotator cuff keeps the top of your arm centered in the shoulder joint. The infraspinatus averaged 71–79% MVIC in Youdas's study, and Urbanczyk's model put the largest share of muscle stress on the rotator cuff in the reverse grip: 30%, versus 25% for the standard pronated grip and 20% for the wide grip.

7. Forearms and Grip

Your forearm flexors hold you on the bar for the whole set, and a weak grip can end it before your back tires. In a 2025 study by Sepehri Rahnama and colleagues (Sports), 30 physically inactive male students did the same pull-up program for 8 weeks with different add-ons. Those who added forearm training gained significantly more pull-up reps than the other groups, going from about 4 to about 13, and more right-hand grip strength than the core group. Hanging time and left-hand grip didn't differ significantly between groups. The study was small, with 10 men per group, and its participants started from a low base.

Towel pull-ups felt hardest to Snarr's participants, though the study didn't measure grip, and they didn't change lat, biceps, or rear-delt activity.

8. Core and Lower Back

Your abs and lower back keep your body from swinging. In Youdas's study, the external obliques averaged 31–35% MVIC and the erector spinae 39–41%. That's moderate bracing, and the study didn't measure the rectus abdominis.

Kipping changes the picture. In Dinunzio et al. (2019) (Sports Biomechanics), adding a kip raised rectus abdominis activity by 28.7% of MVIC and external oblique activity by 21.8%, and lowered biceps activity by 26.7%. See Best Ab Exercises Ranked for direct core work.

How Hand Position Changes the Work

Youdas and Dickie agree that the main muscles work on every grip, and they differ on how much hand position matters.

If you want more biceps, a chin-up grip is the best-supported choice. If you want more mid-back work than a neutral grip gives, use a pronated grip. For a full comparison, see Pull-Up vs Chin-Up vs Neutral Grip.

How Grip Width Changes the Work

A wide grip is the classic "lat width" advice, but the evidence for it is thin:

• On the pull-up: Ortega-Rodríguez et al. (2021) tested 14 trained men at shoulder width and at a freely chosen grip that averaged 20% wider. One-rep max, reps to failure, and power didn't differ; the study didn't measure lat activity. A 2026 narrative review of EMG studies by Di Fonza and colleagues found lat activity broadly similar across pull-up grips.
• On the lat pulldown: Andersen et al. (2014) compared grips of 1, 1.5, and 2 times shoulder width in 15 men. Lat, trapezius, and infraspinatus activity was similar over the whole movement, though wide beat narrow for the lats on the lowering phase, and the widest grip lifted the least: 77.3 kg versus about 80 kg for six reps. Signorile et al. (2002) did find more lat activity with a wide grip in front of the head than with a close or supinated grip, so the studies don't fully agree.
• In a computer model: Urbanczyk found a wide grip shifted a larger share of muscle stress to the lats, traps, and rhomboids, though the same main muscle groups did the work in all three grips.
• Shoulder load: in Pouly et al. (2026) (Sports Biomechanics), 21 men did pull-ups at four grip widths and three hand angles. A wide hand position raised the net load on the shoulder by 7%, and the authors advise caution with it.

Wide and chin-up grips both come with a caution. In Prinold and Bull (2016) (Journal of Science and Medicine in Sport), wide and reverse-grip pull-ups showed shoulder movement patterns the authors linked to a higher risk of subacromial impingement, and they noted that the reverse grip is often given to weaker lifters because it feels easier. Those are movement patterns, not injury counts, but they're a reason not to force either grip.

Use the width that lets you pull through a full range of motion without shoulder discomfort. The wide-grip pull-up and neutral-grip pull-up are both good options if your shoulders tolerate them.

Assisted and Negative Pull-Ups

If you can't do a strict pull-up yet, you have three main options. The evidence here is limited, and none of the studies below tested lifters who can't yet do a pull-up.

• Assisted pull-ups: Prinold and Bull suggested weight-assisted pull-ups with a standard grip could suit weaker lifters, an idea they didn't test. Urbanczyk's authors also suggest pulldowns and weight-assisted pull-ups as ways to work at a reduced share of the full load.
• Negatives (jump or step up, then lower slowly): Dickie measured less biceps, brachioradialis, and pectoralis major activity on the way down than on the way up in normal reps. That doesn't mean less load, and the study didn't test stand-alone negatives. In Vigouroux and Devise (2024), 8 advanced climbers raised their pull-up one-rep max by 5% in 5 weeks of loaded 5-second negatives plus explosive reps, but they aren't beginners, and isometric and plyometric training also raised one-rep max.
• Lat pulldowns: in Li's study, men who could already do about 2 pull-ups reached about 6 after 8 weeks of standard lat pulldowns. Anyone who couldn't do one pull-up was excluded, so this doesn't show pulldowns get you your first rep.

All three groups in Sepehri Rahnama's study used assisted, reverse-grip, and negative pull-ups plus inverted rows, starting from about 3–4 reps, and reps rose in every group. There was no group without that program, so it shows association only. We found no study measuring which muscles grow from assisted or negative pull-ups. For a step-by-step path to your first rep, see the "How to Build From Zero Pull-Ups" section of Pull-Up vs Chin-Up vs Neutral Grip.

Why You Feel Pull-Ups in Your Arms

It's the most common complaint, and it usually isn't a sign your back is idle. The lats were the most active muscle reported in Youdas's study. Why the arms are easier to feel hasn't been tested in the studies we found, so treat that as coaching experience.

Cues can help. In Snyder and Leech (2009), eight untrained women did light lat pulldowns before and after technique coaching. Lat activity rose after the coaching, but biceps activity didn't change. The authors concluded the increase probably isn't true isolation, so don't expect your arms to go quiet.

Start each rep by pulling your shoulder blades down, then drive your elbows toward your hips. Use the full range: Urbanczyk's authors stressed that different phases of the pull-up emphasize different muscles.

How to Bias Each Muscle

For lats: any grip works, and a pronated grip at a comfortable width is a reasonable default. Start from a full hang and pull your elbows toward your hips. Add the lat pulldown for extra volume. See Best Back Exercises for Width and Thickness.

For biceps: use a chin-up grip, and add direct curls if you want more.

For the mid-back: use a pronated grip and squeeze your shoulder blades down and back at the top. Add rows; see T-Bar Row vs Bent-Over Row vs Seated Cable Row.

For grip: add wrist curls and farmer's walks, two of the add-ons in Sepehri Rahnama's study. Dead hangs are a common coaching option.

For the core: stay strict, then add direct ab work.

For sets, reps, and weekly volume, see the best rep range for hypertrophy and sets per week for muscle growth.

Common Mistakes That Change Which Muscles Work

• Cutting the bottom short: half reps skip the part where your shoulder blades move. Cue: start each rep from a controlled hang.
• Pulling with your arms first: this hasn't been tested on the pull-up, but on the lat pulldown coaching raised beginners' lat activity (Snyder and Leech). Cue: shoulder blades down, then elbows to hips.
• Kipping when you want a strict pull: a kip raises core and hip activity and lowers biceps activity (Dinunzio). It's a different exercise, so use it deliberately.
• Forcing a wide grip: on the lat pulldown it doesn't clearly add lat activity (Andersen), and it may raise impingement risk (Prinold).
• Expecting pull-ups to be your ab work: oblique activity is moderate (Youdas). Add direct ab work.

The Bottom Line

Pull-ups are led by the lats and biceps, with the teres major, rear delts, brachialis, and brachioradialis helping. The lower and middle traps, rotator cuff, forearms, and core keep your shoulders and torso stable. In Youdas's study, a chin-up grip added biceps and chest and a pull-up grip added lower traps; in Dickie's, a pronated grip added middle traps compared with a neutral grip. Grip width matters less than its reputation suggests, and both wide and chin-up grips carry a shoulder caution. The evidence is mostly EMG, so treat these as patterns of activity, not guarantees of growth. Pick a grip your shoulders like, use a full range of motion, and add rows and direct arm or ab work where you need more.

For more back training, see Best Back Exercises for Width and Thickness, Lat Pulldown: Wide vs Close vs Neutral Grip, and What Muscles Does the Deadlift Work.