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By The Angles90 Editorial Team · Published 09.26.2026 · Last updated 09.26.2026
A chin-up is a pull-up done with your palms facing you. Hands go about shoulder-width apart, you start from a straight-arm hang, and you pull until your chin clears the bar. It trains the same big back muscles as the overhand pull-up, and in a 2010 Mayo Clinic study it put more work through the biceps and chest than the overhand version did.
Angles90® has been building pulling equipment since 2018, starting with a handle co-developed with the strength training ergonomics faculty at TU Munich. Pulling is the movement we spend most of our time on, and the chin-up is one of the simplest ways to train it.
A chin-up is a vertical pull with a supinated, or underhand, grip: your palms face you. Flip your hands so the palms face away and the same movement becomes a pull-up. With the palms facing each other, you have a neutral-grip pull-up.
The hand position matters because of what it asks of your forearm. Your biceps does more than bend the elbow. StatPearls' anatomy review of the biceps (updated 01.30.2024) describes it as the forearm's most powerful supinator once the elbow is bent, which makes it the main muscle that turns your palm up. A chin-up holds the palm in exactly that turned-up position while the elbow bends under your full body weight.
Start from a full hang, pull your chest toward the bar until your chin clears it, then lower all the way back down under control. Step by step:
The faults to watch for are kipping or swinging your way up, stopping short of straight arms at the bottom, and craning your chin upward at the top instead of finishing the pull with your back.
Neither is better across the board. The measured difference between them is smaller than a lot of gym advice assumes, a point the authors of the 2017 study below make directly, so pick by goal and by how each one feels in your elbows and wrists, and train both if you can.
The two best-known lab studies don't fully agree. In the Mayo Clinic study of 25 adults (Youdas et al., 2010), the chin-up produced higher biceps and pectoralis major activity than the pull-up, while the pull-up worked the lower trapezius harder. The lats were the most active muscle measured in both. A 2017 study of 19 strength-trained men in the Journal of Electromyography and Kinesiology (Dickie et al.) compared supinated, pronated, neutral and rope grips across eight shoulder, arm and forearm muscles and found activation broadly similar whatever the hand position. Its one clear difference was more middle-trapezius activity with the overhand grip than with the neutral grip.
Read together, grip orientation shifts the emphasis at the margins. Your lats carry the load in every version, and the grip decides how much help they get from the arms and upper back. If you want the full menu of hand positions on a bar, our guide to different pull-up grips covers eight of them.
| Variation | Palms face | What the lab studies reported |
|---|---|---|
| Chin-up | Toward you (supinated) | Higher biceps and pectoralis major activity than the pull-up (Youdas et al., 2010) |
| Pull-up | Away from you (pronated) | Higher lower-trapezius activity than the chin-up (Youdas et al., 2010); more middle-trapezius activity than the neutral grip (Dickie et al., 2017) |
| Neutral-grip pull-up | Toward each other | Broadly similar activation to the other grips across eight muscles, apart from less middle-trapezius activity than the overhand grip (Dickie et al., 2017) |
Chin-ups mainly work your lats, with the biceps as the biggest helper, plus the muscles that control your shoulder blades and some of your chest. In the Mayo Clinic study, the latissimus dorsi was the most active of the seven muscles measured, followed by the biceps and the infraspinatus, one of the rotator cuff muscles. The lower trapezius, pectoralis major, erector spinae and external obliques contributed as well.
Where the effort lands also depends on the phase of the rep. The 2017 study found the pulling-up phase produced more biceps, brachioradialis and chest activity than the lowering phase, which is useful to know once you start working on negatives (more on those below).
A straight bar fixes your hand position for the whole rep. Rings, straps and freely rotating handles let your hands turn as you pull.
On a bar, your palms face you at the bottom and they still face you at the top, because the grip is decided before the rep starts. Your forearm can turn, and turning the palm up is the job the biceps does best, as the anatomy above shows. A fixed bar just doesn't give it that option once the rep is underway.
That's the idea behind the A90 Grips. They're dynamic training grips: a pair of freely rotating handles on straps that loop over the pull-up bar you already have. You can hold them palms-up for a classic chin-up, keep them neutral, or let them turn through the rep, palms facing each other at the bottom and rotating toward you as you pull. Each handle is certified for 400 lbs (180 kg). We designed them as a handle that adapts to you, not the opposite.
When customers describe what changed for them, the most specific thing they mention is this exact move: turning their hands inside a single rep instead of committing to one grip for the whole set. There are also four ways to hold the handles, which we call ERGO, POWER, POWER+ and FOREARM.
Train the parts of the movement you can already do, then join them up. You can combine several of these in one session.
Test a full rep every week or so. Once it comes, our pull-up strength guide covers how to add reps, the upper body bodyweight exercises list has more pulling work to pair with it, and the muscle-up is the next skill on the bar.
They can be. In the Mayo Clinic study the chin-up drew more on the biceps than the pull-up did, so your arms contribute more. The reliable way to find out for yourself is to test your max reps of each on the same day, with a good rest in between.
It trains the muscles that pull your arms down and back, led by the lats, along with the biceps, the muscles around your shoulder blades and some chest. In the 2017 study, peak activation during pull-up variations was high enough to promote adaptation in the lats, biceps, brachioradialis and infraspinatus.
Shoulder-width is the standard setup and the one used in the research. Much narrower or wider changes how the movement feels, so find the width where your elbows track comfortably and keep it consistent from set to set.
Yes. Loop the straps over the bar, then hold the handles palms-up for a classic chin-up or let them rotate through the rep. They attach to any bar, and each handle is certified for 400 lbs (180 kg).
Stop the set. Pain is a reason to get assessed by a qualified healthcare professional before you keep training the movement.
Angles90 products are training equipment, not medical devices. This article is general information about training, not medical advice, diagnosis or treatment. If you are training around pain, an injury or a medical condition, speak to a qualified healthcare professional before changing how you train.
Hang with straight arms and your palms facing you, drive your elbows to your ribs until your chin clears the bar, and lower slowly. Build toward it with hangs, scapular pulls, rows and negatives. If you'd like your hands free to turn through the rep, see how the A90 Grips fit on the bar you already train on.
