The Bayesian curl is a cable curl performed with the arm extended behind the body — similar to an incline dumbbell curl but with constant cable tension throughout. Named after biomechanist Menno Henselmans, it has become one of the most popular evidence-based biceps exercises for long-head development.
What it is
The Bayesian curl is a single-arm cable curl performed facing away from a low pulley with the working arm extended behind the body. The lifter steps forward and curls the handle from behind. The cable provides constant tension at the deeply stretched bottom position — exactly what the biceps’ long head needs for hypertrophy.
Muscles worked
| Muscle | Contribution |
|---|---|
| Biceps long head | ~55 % |
| Biceps short head | ~20 % |
| Brachialis | ~15 % |
| Brachioradialis, forearms | ~10 % |
How to Bayesian curl: 5 steps
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Set up the cable
Set the pulley to the **lowest setting with a single-handle attachment.**
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Face away
**Face away from the pulley.** Step forward so the cable runs behind your body.
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Stretch the arm back
**Grip the handle with the working arm extended behind the body.** Supinated grip.
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Curl up
**Curl by flexing the elbow only.** Hand travels from behind to in front of the body.
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Controlled descent
**Lower over 3 seconds** back to the stretched position. Complete reps, switch sides.
How it differs from cable curl
- Arm extended behind body. Facing away from the pulley — the long head is fully stretched at the start.
- Constant tension. Cable maintains load throughout — even in the stretched position.
- Long-head focus. Best evidence-based exercise for peak development.
- Unilateral. One arm at a time corrects imbalances.
Common mistakes
When to use this variation
Use Bayesian curls for evidence-based long-head biceps hypertrophy. Program 3 sets of 10-15 reps per arm. Pair after heavy compound curls or as a focused finisher. Modern hypertrophy programs often include it as the primary biceps exercise rather than as a supplement.
FAQ
Why is it good for the long head?
The long head crosses the shoulder. With the arm extended behind the body, the long head starts in a fully stretched position. Combined with cable’s constant tension, this maximises long-head growth.
Pulley height?
Set the pulley at the lowest setting. The cable should run from below behind you, up to your hand.
Bayesian curl or incline dumbbell curl?
Both bias the long head. The incline dumbbell curl has dropoff at the top (gravity vertical); Bayesian has constant tension. Bayesian is mechanically superior, but both work.
Related exercises
- Cable Curl: front-facing version
- Incline Dumbbell Curl: dumbbell long-head equivalent
- Dumbbell Curl: standard standing version
- Concentration Curl: another single-arm isolation