Bicep curl machines look straightforward—sit down and curl. But proper setup and technique make a significant difference in results. Let me walk you through exactly how to use these machines effectively.
Types of Bicep Curl Machines
Before we discuss technique, understand that there are several types:
Preacher curl machine: Arms rest on an angled pad in front of you. The most common type. Mimics the preacher curl bench.
Seated curl machine (arms at sides): Sitting upright with arms hanging down, you curl handles upward. Less common but found in some gyms.
Plate-loaded curl machine: Same mechanics as selectorized versions but you load plates manually instead of using a pin.
The following guide applies primarily to preacher-style machines since they're most common, but principles transfer to other types.
Step 1: Adjust the Seat Height
This is the most important setup step and where most people go wrong.
For preacher curl machines:
• Sit in the seat and rest your arms on the pad
• Your armpits should be at the top edge of the pad
• Your entire upper arm (tricep) should rest flat against the padding
• There should be no gap between your arm and the pad
If the seat is too high:
• The pad will hit your chest instead of your armpits
• Range of motion will be limited
• Shoulders may try to help lift
If the seat is too low:
• The pad will hit mid-arm
• Upper arms won't be fully supported
• Tendency to lift elbows off the pad
Take time to get this right. Adjust the pin or lever until your armpits sit right at the pad's top edge.
Step 2: Position Your Chest and Back
Chest: Press your chest against the back of the arm pad (if the machine has one). This prevents you from leaning back as you fatigue.
Back: Maintain a neutral spine. Don't round forward or arch excessively.
Shoulders: Pull them back slightly and keep them down. Don't let shoulders shrug up during the movement.
Step 3: Grip the Handles
Standard grip:
• Palms facing up (supinated)
• Grip firm but not death-gripping
• Wrists neutral or slightly flexed—never bent backward
Grip width:
• Some machines have multiple grip options
• Wider grip: slightly more short head emphasis
• Narrower grip: slightly more long head emphasis
• Start with whatever feels natural, experiment later
Step 4: Execute the Curl
Starting position:
• Arms extended, slight bend in elbows (5-10 degrees)
• Never fully lock out or hyperextend elbows
• Upper arms stay pressed against pad
The concentric (lifting) phase:
• Initiate movement by contracting biceps, not pulling with hands
• Curl the handles up toward your shoulders
• Keep upper arms stationary—only forearms move
• About 2 seconds to lift
The peak contraction:
• At the top, squeeze your biceps hard
• Hold for 1 full second
• Feel the contraction in the muscle
The eccentric (lowering) phase:
• Lower the weight slowly—3 seconds minimum
• Resist the weight, don't let it drop
• Maintain tension throughout
• Return to starting position (slight elbow bend)
Breathing:
• Exhale as you curl up
• Inhale as you lower
• Never hold your breath
Common Mistakes and How to Fix Them
Lifting elbows off the pad:
• Problem: Shifts work to shoulders
• Fix: Reduce weight, consciously keep arms pressed down
Partial range of motion:
• Problem: Missing the stretch at bottom or squeeze at top
• Fix: Go all the way down, all the way up on every rep
Using momentum/swinging:
• Problem: Reduces bicep work, increases injury risk
• Fix: Slow down, use lighter weight
Letting weight stack touch between reps:
• Problem: Eliminates tension, allows rest
• Fix: Stop just before weights touch, maintain continuous tension
Rushing through reps:
• Problem: Momentum doing the work, less time under tension
• Fix: Each rep should take 5-6 seconds total
Programming Machine Curls
For muscle growth:
• 3-4 sets of 10-12 reps
• 60-90 seconds rest between sets
• Add weight when you can complete all reps with good form
For pump/endurance:
• 2-3 sets of 15-20 reps
• 45-60 seconds rest
• Lighter weight, focus on contraction
Drop sets (machines are perfect for this):
• Do a set to failure
• Immediately reduce weight by 20-30%
• Rep to failure again
• Repeat 2-3 times
Where to Place Machine Curls in Your Workout
After compound movements: Do your rows, pulldowns, or chin-ups first. Then use the machine for isolation work.
As a finishing exercise: Machine curls are excellent for burnout sets at the end of your arm or pull workout.
On arm-specific days: If you have a dedicated arm day, machines can be placed anywhere in the session.
The Bottom Line
Bicep curl machines are effective tools when used correctly. Take time to set up properly (especially seat height), maintain strict form, control the weight through full range of motion, and progressively overload over time.
The machine does the work of stabilization for you—your job is to contract your biceps as hard as possible through every rep.