Cable Single-Arm Preacher Curl
What Is the Cable Single-Arm Preacher Curl?
Cable Single-Arm Preacher Curl is an isolation exercise that primarily targets the biceps, with strong help from the brachialis and support from the brachioradialis. It is a beginner-level movement, done seated with the upper arm pinned on an angled pad so the elbow flexors do the lifting.
The cable changes where the curl is hardest. With a barbell or dumbbell, the load is heaviest with the arm low on the pad and almost disappears as the forearm comes upright at the top. A low pulley in front of the bench keeps pulling on the handle through the top of the curl, so the biceps stay loaded where free weights go slack. Pulley height and the distance between the bench and the stack decide where the hardest point falls.
Doing this movement one arm at a time allows for better focus on the muscle contraction and helps correct imbalances between arms. It's particularly effective for lifters who want to isolate the biceps without help from shoulders or body momentum.
It usually comes late in an arm or pull session, after heavier compound pulls and free-weight curls. A 10-week study in previously untrained young men found that single-arm cable preacher curls grew the biceps and the brachialis about as much as single-arm cable curls done with the arm drawn behind the body, when both were set up to load the same part of the range.
Muscles Worked
- Biceps Brachii
- Primary
- Brachialis
- High
- Brachioradialis
- Medium
- Deltoid
- Minimal
Instructions
- Set the preacher bench in front of a low pulley cable machine, with the angled pad facing the stack.
- Attach a single handle to the low pulley.
- Sit down with your feet flat and rest one arm over the preacher bench with your armpit snug against the top.
- Grab the handle with an underhand grip (palm up), your arm extended down the pad with a slight bend at the elbow.
- Keep the back of your upper arm pressed into the pad for the whole set.
- Curl the handle upward toward your shoulder by flexing your bicep.
- Pause at the top for a strong contraction.
- Slowly lower the weight back down until your arm is almost straight, keeping the cable taut.
- Repeat for the desired number of reps, then switch arms.
Common Mistakes
Letting the elbow move
Shifting the elbow forward or back reduces bicep isolation and adds shoulder involvement.
Using momentum
Jerking the handle up reduces tension on the biceps and increases injury risk.
Shortening the range of motion
Stopping well short of a nearly straight arm at the bottom cuts out the stretched part of the rep and limits growth potential.
Rushing the negative
Letting the cable pull your arm down quickly misses out on the eccentric training benefits.
Leaning back to finish the rep
Rocking the torso away from the pad at the top lifts the upper arm and turns the curl into a shoulder movement.
Injuries
Cable Single-Arm Preacher Curl is a low risk exercise when performed with proper technique.
The fixed arm position reduces shoulder and lower back involvement, but improper weight selection or rushed reps can strain the elbow tendons or cause biceps tendon irritation. Gradually increase the load over time and maintain control during both the concentric and eccentric portions.
The most demanding point is the bottom of the rep, where the elbow is almost straight and the distal biceps tendon below the elbow crease is under stretch. Lower the handle under control to a nearly straight arm without snapping the elbow into lockout, and never let the cable yank the arm straight. Warm up with lighter curls or dynamic stretches targeting the elbow and forearm before your working sets.
If the bottom of the rep bothers your elbow, use a lighter weight and stop a little short of straight, or switch to a standing Cable Single-Arm Curl. To progress, add load in small steps or slow the lowering phase. Stop the set if you feel sharp pain at the front of the elbow or a pop, and have a sudden loss of curling strength or a change in the shape of the biceps checked, as these can signal a biceps tendon injury.
Frequently Asked Questions
- Q: Can I use a rope instead of a handle for this exercise?
You can, but holding one end of a rope turns your palm to face inward, which makes it a hammer-style preacher curl with more brachioradialis work. Keep the single handle with your palm up for the version shown here.
- Q: Is the cable version better than a free-weight preacher curl?
Neither is clearly better for size. In a 10-week study on untrained young adults, two-handed cable and barbell preacher curls built similar biceps thickness, though the barbell group gained more strength with the elbow nearly straight. The cable keeps the top of the curl loaded, while free weights load the bottom.
- Q: Where should the pulley and bench go?
Set the pulley at its lowest position and place the bench so you face the stack, close enough that the cable is taut when your arm is almost straight on the pad. Moving the bench closer or farther changes the cable angle and where the curl feels hardest, so adjust it until the bottom of the rep never goes slack.
- Q: How many reps should I do for bicep growth?
8 to 12 reps per arm for 3 to 4 sets is a solid range for hypertrophy.