Dumbbell Single-Arm Triceps Extension
What Is the Dumbbell Single-Arm Triceps Extension?
Dumbbell Single-Arm Triceps Extension is an isolation exercise that primarily targets the triceps and also engages the shoulders and core for stability. It is an intermediate-level movement performed standing, one arm at a time, with the dumbbell lowered behind the head from a straight-arm overhead position while the free hand rests on the hip.
With the arm overhead, the long head of the triceps, the only head that crosses the shoulder, works from a lengthened position. That is the main reason to choose an overhead extension over a pushdown. In a 12-week study of 21 adults doing cable elbow extensions with one arm overhead and the other at their side, the overhead arm gained about 1.4 times more triceps muscle volume, with the biggest difference in the long head, even though it lifted lighter loads.
The standing position asks the trunk to hold the ribs down and resist leaning away from the weight, so balance and bracing are part of every rep. The seated version takes most of that away and lets you focus on the arm alone. Working one arm at a time also shows up strength differences between sides and keeps the stronger arm from covering for the weaker one.
This extension usually comes near the end of an upper-body or arm session, after pressing work, and suits lifters who want more triceps size or lockout strength. It needs comfortable overhead shoulder mobility. If raising the arm fully overhead feels restricted or pinches, build up with the Cable Single-Arm Overhead Triceps Extension or the Dumbbell Overhead Triceps Extension with both hands on one dumbbell, where the load is easier to control.
Muscles Worked
- Triceps Brachii (Long Head)
- Primary
- Deltoid
- Medium
- Erector Spinae
- Minimal
- Flexor Carpi Radialis
- Minimal
Instructions
- Stand tall with your feet about hip-width apart, hold a dumbbell in one hand and rest your free hand on your hip.
- Press the dumbbell overhead until your arm is straight and your upper arm is beside your head, palm facing forward.
- Brace your core and keep your ribs down so your lower back does not arch.
- Keeping your upper arm still and your elbow pointing up, bend the elbow to lower the dumbbell slowly behind your head, letting it travel slightly toward the opposite shoulder.
- Lower until you feel a deep stretch in the back of the upper arm, with your forearm about parallel to the floor or as far as your shoulder allows without pain.
- Straighten your elbow to press the dumbbell back overhead, moving only at the elbow.
- Complete your reps, then switch arms.
Common Mistakes
Using Excessive Weight
A dumbbell that is too heavy cuts the range short, invites momentum and strains the elbow, so pick a load you can lower slowly behind your head.
Flaring the Elbow
Letting the elbow drift out or forward moves the upper arm and shifts tension away from the triceps, so keep the elbow pointing up beside your head.
Arching the Lower Back
Leaning back to get the arm overhead stresses the lower spine, so brace your core and keep your ribs down throughout the set.
Dropping Into the Stretch
Letting the dumbbell fall quickly behind the head loads the elbow tendon hardest at its most stretched point, so control the lowering phase.
Cutting the Range Short
Stopping well above the stretch skips the lengthened position that makes the overhead extension worth doing, so lower until your forearm is about parallel to the floor if your shoulder allows.
Injuries
Dumbbell Single-Arm Triceps Extension is a medium risk exercise when performed with proper technique. The overhead arm position and the deep stretch at the bottom place the elbow and shoulder under load at the same time.
The usual strain point is the triceps tendon at the back of the elbow, which is loaded hardest where the dumbbell is lowest behind the head. Heavy weights, fast lowering and high weekly volume make it worse. Limited overhead shoulder mobility is the second problem: the elbow drifts forward or out, the shoulder can pinch at the top, and the lower back arches to make up the difference. Warm up the shoulders and elbows, use a load you can lower slowly, brace the core and only lower as far as your shoulder allows without pain.
If the standing version is hard to control, sit instead with the Dumbbell Seated Single-Arm Triceps Extension, or use the Cable Single-Arm Overhead Triceps Extension, which is smoother at the bottom. When overhead work bothers the shoulder, train the triceps with the arm at your side, such as the Dumbbell Single-Arm Triceps Kickback or the Cable Triceps Pushdown (Rope). Progress by adding reps and a slower lowering phase before adding weight.
Stop the set if you feel sharp pain at the back of the elbow, a pinch at the front or top of the shoulder, or numbness or tingling down the arm.
Frequently Asked Questions
- Q: Should I do this exercise standing or seated?
Both work the triceps the same way. Standing adds a balance and bracing demand, while the seated version removes it so you can focus on the arm, which helps if your lower back tends to arch.
- Q: Where should the dumbbell go at the bottom?
Behind your head, with the upper arm still pointing up. It is normal for the dumbbell to travel slightly toward the opposite shoulder as the forearm passes behind the head.
- Q: How heavy should the dumbbell be?
Choose a weight you can lower slowly for 8 to 15 reps with the elbow staying still. Expect to use less than on pushdowns, because the triceps work from a stretched position overhead.
- Q: Why does my elbow hurt during overhead extensions?
Usually the load is too heavy, the dumbbell drops too fast into the bottom, or the elbow flares out. Lighten the weight, slow the lowering phase and shorten the depth, and switch to a pushdown if the pain continues.