Single Arm Cross Body Tricep Extension

The single-arm cross-body triceps extension is a cable isolation exercise performed one arm at a time, extending the elbow diagonally across the body against constant tension. Working unilaterally lets you correct strength imbalances between arms and keeps the working elbow locked into a fixed, diagonal path that isolates the triceps more strictly than a straight-line pushdown. The cross-body angle also places the shoulder in slight horizontal adduction, shifting more emphasis onto the long head of the triceps.

Muscles Targeted

• Primary: Triceps brachii (all three heads, with emphasis on the long head)
• Secondary: Anterior deltoid, core stabilizers
• Tertiary: Forearm flexors (grip)

Starting Position

Set a low pulley to about hip height and attach a single D-handle. Stand side-on to the machine, feet shoulder-width apart, and grasp the handle with the hand farther from the machine so the cable crosses in front of your torso. Bend the elbow so your hand sits near your opposite hip or lower ribs, with your upper arm pinned close to your side.

Execution Steps

1. Brace your core and pin the upper arm to your side so only the forearm moves through the exercise
2. Extend your elbow by driving your hand down and across your body until the arm is fully straight
3. Squeeze the triceps hard at full extension, holding the contraction for a one-count
4. Reverse the motion slowly, allowing the elbow to bend and the handle to travel back across your body under control
5. Stop the return once your hand reaches your opposite hip, keeping tension on the cable rather than letting the weight stack touch down
6. Complete all reps on one side before switching arms

Form Cues

• Keep the upper arm fixed: Movement should occur only at the elbow joint, not the shoulder
• Drive across the body, not down: The path is diagonal, following the cable's natural line to the low pulley
• Control the eccentric: Resist the cable on the way back rather than letting it snap your arm into flexion
• Brace the torso to prevent rotating or leaning to generate momentum
• Keep the wrist neutral and grip firm through the entire rep

Common Mistakes

• Letting the elbow drift away from the body: This turns the movement into a shoulder-dominant press and reduces triceps isolation. Keep the upper arm glued to your side.
• Using body english to swing the weight: Twisting the torso for momentum shortcuts the triceps' work. Slow down and use a weight you can control strictly.
• Partial range of motion: Stopping short of full elbow extension leaves gains on the table. Finish each rep with a complete, locked-out squeeze.
• Standing too close or too far from the pulley: Incorrect distance changes the cable angle and reduces the cross-body line of pull. Set up so the cable travels diagonally across your torso.

Variations

• Cable rope cross-body extension: Using a rope instead of a D-handle allows a slight wrist rotation at lockout
• Standing overhead cable triceps extension: Changes the resistance curve to emphasize the long head from a stretched position
• Dumbbell cross-body extension: A free-weight alternative using a single dumbbell for a similar diagonal path
• Bent-over cable kickback: Shifts torso angle to work the triceps from a horizontal plane

Tips for Progression

• Add small weight increments (2.5-5 pounds) once you can complete all sets with a strict, controlled path
• Slow the eccentric phase to 3-4 seconds to increase time under tension without adding load
• Add a brief pause at full extension on your final set to intensify the peak contraction
• Progress from 12-15 reps at lighter loads toward 8-10 reps as strength improves

Training Notes

Program the single-arm cross-body triceps extension as an isolation finisher after compound pressing work like bench press or dips, 1-2 times per week per arm. Use 3 sets of 10-12 reps per side with 45-60 seconds of rest between sets, and always complete both arms before moving to the next exercise.