Cable One Arm Tricep Extension
The cable one arm tricep extension isolates a single triceps at a time, pulling an overhead handle down and forward while your working elbow stays fixed in place. Training one arm at a time removes any chance of your stronger side compensating for a weaker one, which a two-handed pushdown or extension can easily hide. It's a useful addition for lifters who notice one arm lagging behind the other, or anyone who wants extra triceps volume without adding more load to a two-arm exercise.
Why it works
Your triceps' entire job is straightening your elbow, and training one arm at a time forces that single muscle to handle the full resistance without any help from the opposite side stepping in. A two-arm pushdown or extension can mask an imbalance because your stronger arm picks up extra work without you noticing, something a single-arm cable movement makes obvious immediately. Working overhead also changes the length of your triceps compared to a pushdown done with your elbow at your side, giving the long head of the muscle, which crosses your shoulder joint, a deeper stretch at the bottom of each rep. Because only one arm carries the cable, you can also focus completely on the working side's elbow position and squeeze, without the coordination demands of moving two arms symmetrically at once.
Set up
- Set a cable pulley to a high position and attach a single handle.
- Stand facing away from the machine, gripping the handle with one hand overhead, elbow bent and pointing toward the ceiling.
- Pin your upper arm close to your ear, using your free hand to support it if it helps you stay still.
- Step forward until the cable carries tension before your first rep.
How to do it
- Keeping your upper arm still, straighten your elbow and extend the handle up and slightly forward.
- Squeeze your triceps hard at full extension.
- Lower the handle back behind your head under control, letting your elbow bend fully.
- Stop the descent once you feel a full stretch, without your upper arm drifting away from your ear.
- Complete the full set on one arm before switching sides.
Form cues
- Upper arm pinned by your ear the whole set.
- Extend fully, then squeeze at the top.
- Lower slow enough to feel the stretch.
- Keep your torso still, don't lean to help the lift.
Breathing: Exhale as you extend your elbow and press the handle overhead, and inhale as you lower it back into the stretch.
Common mistakes
Letting the working elbow drift forward or out to the side during the extension.
Fix: Keep your upper arm pinned against your ear and isolate the movement to your forearm.
Twisting or leaning the torso to help push through a heavy rep.
Fix: Keep your torso square and use a lighter weight until your triceps alone can complete the range.
Rushing through reps without pausing at full extension.
Fix: Pause briefly and squeeze deliberately at the top of each rep before lowering back down.
How to program it
- As a unilateral isolation move, three sets of ten to twelve reps per arm placed after your main pressing work trains the triceps directly without pre-fatiguing your pressing strength.
- It's especially useful on a day where you've noticed one arm lagging, since training single-sided closes gaps that two-arm exercises tend to hide.
- Twice a week is a sensible ceiling for most lifters, since training one arm at a time roughly doubles the total sets for the same triceps volume compared to a two-arm version.
Safety notes
- Support your working upper arm with your free hand if you have trouble keeping it still.
- Use a weight light enough that your torso doesn't need to twist or lean to complete the rep.
- Stop short of a hard, painful stretch at the bottom, a comfortable deep stretch is the goal, not the limit of your range.
Exercise profile
- Force
- Push
- Mechanics
- Isolation
- Category
- Strength
Frequently asked questions
How many sets and reps of cable one arm tricep extensions should I do?
Three sets of ten to twelve reps per arm is a solid default, since single-arm work naturally takes more total sets to match the volume of a two-arm exercise.
Can I do a single-arm triceps extension without a cable machine?
Yes. A dumbbell one arm triceps extension trains the same pattern, and a standing towel triceps extension needs no equipment at all.
Why train triceps one arm at a time instead of both together?
Training one side at a time stops your stronger arm from covering for a weaker one without you noticing, which makes it a good tool for evening out side-to-side strength differences.
Why does my shoulder move during this exercise?
If your upper arm drifts away from your ear, your shoulder is likely taking over from your triceps. Support your upper arm with your free hand and keep it fixed in place through the whole set.