The decline bicep curl is one of those exercises you rarely see in gyms, yet it's remarkably effective for long head development. If you're chasing that bicep peak, this underrated movement deserves your attention.
What Makes Decline Curls Different
On a decline bench, your arms hang behind your body when at full extension. This position stretches the long head of your biceps—the head responsible for the "peak" you see when flexing.
This is the opposite of preacher curls, where your arms are forward (shortening the long head and emphasizing the short head). Decline curls flip that emphasis.
The biceps brachii crosses two joints—the shoulder and the elbow. The long head starts at the shoulder blade, so shoulder position affects how much it's stretched. When your arm is behind your body, the long head is stretched maximally at the bottom of a curl.
How to Set Up Decline Curls
Equipment needed: A decline bench (or adjustable bench set to decline) and dumbbells. You can also use a cable machine with a decline bench.
Bench angle: 30-45 degrees of decline works well. Steeper angles increase the stretch but may be uncomfortable for some people. Start moderate and adjust based on feel.
Body position:
• Lie face-up on the decline bench
• Secure your feet under the pads
• Let your arms hang straight down toward the floor
• Hold dumbbells with palms facing forward (supinated)
Proper Decline Curl Technique
Starting position: Arms fully extended, hanging straight down. You should feel a stretch in your biceps—that's the point. Keep a slight bend in your elbows (don't hyperextend).
The curl: Without moving your upper arms, curl the dumbbells by contracting your biceps. Think about driving your pinkies toward your shoulders.
Top position: Curl until your forearms are roughly perpendicular to the floor. Squeeze your biceps hard and hold for a second.
The lower: Lower slowly—3 seconds minimum. Feel the stretch return to your biceps. Don't bounce at the bottom.
Throughout: Keep your upper arms vertical (pointed at floor). Only your forearms should move.
Common Decline Curl Mistakes
Bringing elbows forward: When you move your upper arms forward during the curl, you're basically turning this into a regular curl and losing the long head emphasis. Keep arms vertical.
Going too heavy: The stretched position at the bottom is vulnerable. Starting too heavy increases injury risk and forces form breakdown. Use lighter weight than incline or standing curls.
Rushing the stretch: The bottom position is where the magic happens. Don't bounce through it—spend time there under control.
Too steep of decline: Extremely steep angles can be uncomfortable and put your shoulders in a compromised position. 30-45 degrees is plenty.
Muscles Worked During Decline Curls
Primary: Long head of biceps—more emphasized than in almost any other curl variation due to the stretched starting position.
Secondary: Short head of biceps—still works but is somewhat de-emphasized compared to preacher curls.
Secondary: Brachialis—always contributes to elbow flexion.
Secondary: Brachioradialis—assists throughout the movement.
Decline Curls vs. Incline Curls
Both exercises stretch the biceps, but there's a key difference:
Incline curls: Arms hang behind body at the START, then move forward as you curl. The stretch is most pronounced at the bottom.
Decline curls: Similar mechanics, but the decline position can feel different and may allow for a slightly greater stretch depending on your anatomy.
Many people use "incline curl" to describe what we're calling a decline curl here—the terminology gets confused because you're lying on a decline bench but your arms are in an "incline" position relative to your torso.
Whatever you call it, the principle is the same: arms behind body = long head stretch = long head emphasis.
Programming Decline Curls
Sets and reps: 3-4 sets of 10-15 reps. The stretched position responds well to moderate reps with controlled tempo.
Tempo: 2 seconds up, 1 second squeeze, 3-4 seconds down. Emphasize the slow negative.
Weight: Start with about 60-70% of your standing dumbbell curl weight. The position makes the exercise harder.
Frequency: Include once per week if long head development is a priority. Don't overdo stretched-position exercises.
Workout placement: Great as a second or third bicep exercise after heavier compound work.
Sample Long-Head Focused Workout
If building the bicep peak is your goal:
1. Incline dumbbell curl: 3 sets x 10
2. Decline dumbbell curl: 3 sets x 12
3. Drag curl (barbell): 3 sets x 10
4. Narrow-grip preacher curl: 2 sets x 12
This hits the long head from multiple angles while still providing complete bicep stimulus.
When to Use Decline Curls
Good for:
• Prioritizing long head/peak development
• Adding variety to your curl selection
• People who respond well to stretched-position exercises
• Intermediate to advanced lifters looking for specialization
Not necessary for:
• Beginners (master basic curls first)
• People with shoulder issues (the stretched position may be problematic)
• Those already doing incline curls (similar stimulus)
The Bottom Line
Decline bicep curls are a specialized tool for long head development. They're not essential for everyone, but if you're chasing the bicep peak, they deserve consideration.
Focus on the stretch at the bottom, control the movement throughout, and don't go too heavy. The magic is in the position, not the weight.