FITBODY Exercise Library · Arms
45 Degree Bicep Curl
The 45 degree bicep curl, also called the open bicep curl, is a dumbbell curl performed with the arms held out at a 45 degree angle. It biases the long head of the biceps and adds a shoulder stability demand, making it a smart variation for women over 40 building stronger, more defined arms.
How to Do the 45 Degree Bicep Curl
The 45 degree bicep curl, also known as the open bicep curl, is a variation of the classic dumbbell curl that trains the biceps from a new angle. By positioning your arms out at about a 45 degree angle from your torso, you shift the emphasis toward the long head of the biceps and bring the shoulder stabilizers into the movement, which makes it a nice change of pace in any arm routine.
Keep your elbows locked in place. With the women I coach, the whole value of the open curl comes from holding that 45 degree angle and not swinging. Go lighter than your normal curl weight so you can keep the arms steady and feel the biceps working, not your shoulders.
What Muscles Does the 45 Degree Bicep Curl Work?
The 45 degree bicep curl works the biceps brachii, the muscle on the front of your upper arm that flexes the elbow and turns the palm up. Holding your arms out and slightly back puts the long head, which crosses the shoulder, on more of a stretch, which is why lifters use this angle to bias that head, though the biceps still works as one muscle. For a closer look, see this biceps anatomy overview. Curls like this fit naturally into a broader strength training plan for women over 40.
See the full muscle breakdown
- Biceps brachii: the main mover, flexing the elbow and supinating the forearm, with the open angle emphasizing the long head.
- Brachialis: sits underneath the biceps and assists elbow flexion.
- Deltoids: stabilize the arms in the open position, adding a shoulder stability demand.
- Forearm flexors: work to keep a firm grip on the dumbbells throughout the set.
Benefits of the Open Bicep Curl
- Targets the long head of the biceps. The open angle emphasizes the long head, which helps build the peak and a fuller looking upper arm.
- Builds shoulder stability. Holding the arms out engages the deltoids, adding a stability demand the standard curl does not have.
- Improves symmetry. Working each arm on its own reduces reliance on momentum and helps balance the left and right sides.
- Adds variety. A new angle keeps your training fresh and helps you push past plateaus.
Sets and Reps
The 45 degree curl is a control focused move, so choose a weight lighter than your standard curl and keep the arms fixed in the open angle.
| Goal | Sets | Reps |
|---|---|---|
| Muscle building | 3 | 10 to 12 |
| Strength focus | 3 to 4 | 8 to 10 |
| Beginner or returning | 2 to 3 | 12 to 15 |
Rest 60 to 90 seconds between sets. Pick a weight light enough to hold the open angle without swinging or letting the elbows drift forward.
Variations and Progressions
Seated 45 Degree Bicep Curl
Perform the same curl seated on a bench for added stability. Sitting removes momentum and makes it easier to hold the open angle.
Resistance Band 45 Degree Curl
Use resistance bands instead of dumbbells to change the tension profile, with more resistance building toward the top of the curl.
Hammer Grip 45 Degree Curl
Hold the dumbbells in a neutral grip with palms facing each other for a slightly different stimulus that brings in more of the brachialis and forearm.
The 45 degree bicep curl pairs well with the other arm moves in my exercise library, including the hammer curl. Rotate through a few angles so your arms get a complete stimulus.
Common Mistakes to Avoid
- Using too much weight. Heavy dumbbells wreck your form and reduce the effect. Start light and prioritize control.
- Letting the elbows drift forward. Keep your upper arms fixed in the open angle so the tension stays on the biceps.
- Swinging the dumbbells. Momentum steals the work from the muscle. Move each rep slowly.
- Arching the lower back. Keep your core braced and ribs down so the lift stays in your arms.
How to Program It
The 45 degree bicep curl slots easily into an arm day or a full body session. Here is one way to work it into a biceps focused routine:
- Barbell curl: 3 sets of 10 to 12 reps.
- 45 degree bicep curl: 3 sets of 10 to 12 reps.
- Concentration curl: 3 sets of 12 to 15 reps.
- Hammer curl: 3 sets of 10 to 12 reps.
Rest 60 to 90 seconds between sets to keep the intensity up.
45 Degree Bicep Curl FAQs
What is a 45 degree bicep curl?
A 45 degree bicep curl, also called the open bicep curl, is a dumbbell curl where you hold your arms out and slightly away from your torso at about a 45 degree angle instead of at your sides. That open position changes the line of pull on the biceps and adds a stability demand at the shoulders. Because your upper arms are held out to the sides, the movement also asks the deltoids to work to keep the arms steady. It is a simple variation that adds a new stimulus without any special equipment. I use it to add variety and shoulder stability to arm training.
Does the 45 degree bicep curl work the long head of the biceps?
The open arm angle is often used to bias the long head of the biceps, the part that runs along the outside of the upper arm and crosses the shoulder joint. Holding the arms out and slightly back puts that head on more of a stretch, which many lifters find helps them feel it working. It is worth being realistic, though, since the biceps contracts as one muscle and no curl fully isolates a single head. Research shows that shoulder and arm position does change how the biceps is loaded. So the 45 degree curl is a useful tool for adding variety and emphasis, not a way to train only one part of the muscle.
How much weight should I use for 45 degree bicep curls?
Start lighter than you would for a standard curl, because holding your arms in the open position is harder to control and adds a shoulder stability demand. The right weight lets you keep your upper arms fixed at the 45 degree angle without swinging or letting the elbows drift forward. If you have to heave the dumbbells up or your shoulders take over, drop the weight. Clean, controlled reps build the muscle far better than heavy, sloppy ones. You can add small increases over time as your control improves.
What is the difference between a 45 degree curl and a regular curl?
In a regular dumbbell curl your arms stay at your sides, while in the 45 degree or open curl your arms are held out and slightly back at about a 45 degree angle. That change shifts the line of pull on the biceps and puts the long head on more of a stretch, and it adds a stability demand at the shoulders that the standard curl does not have. The open version usually requires a lighter weight because it is harder to control. Neither is better on its own, they simply train the biceps from different angles. I like to rotate both so the arms get a complete stimulus.
Can beginners do the 45 degree bicep curl?
Yes, beginners can do the 45 degree bicep curl, as long as they start light and focus on control. Because the open position adds a shoulder stability demand, it helps to master a standard curl first so you already know how to keep your elbows still. Begin with a weight you can handle for twelve to fifteen clean reps, and do the seated version if standing makes it hard to stay steady. Keep the movement slow and stop if you feel strain in the shoulder rather than work in the biceps. It scales up naturally as your strength and control grow.
References
- Oliveira, Liliam Fernandes de, et al. “Effect of the Shoulder Position on the Biceps Brachii EMG in Different Dumbbell Curls.” Journal of Sports Science and Medicine, vol. 8, no. 1, 2009, pp. 24-29.
- Marcolin, Giuseppe, et al. “Differences in Electromyographic Activity of Biceps Brachii and Brachioradialis While Performing Three Variants of Curl.” PeerJ, vol. 6, 2018, article e5165, doi.org/10.7717/peerj.5165.
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I’m Julie Lohre, an IFBB Fitness Pro and certified personal trainer and nutrition specialist. For more than 20 years I have helped women over 40 get stronger, leaner, and more confident through personalized online coaching built around their real lives.