A cable extension kneeling with the upper arms braced on a bench and a high pulley behind you, which locks the upper arms in place so the triceps work through a long stretch.
Primary muscles
This information is general fitness guidance, not medical advice. Stop if you feel pain and consult a qualified professional.
Main muscles working (thicker lines)
Place a bench crossways in front of a high pulley, hold a straight bar overhead with hands about 15 cm apart, face away from the stack and kneel with the backs of your upper arms on the bench and elbows bent toward the pulley.
Keep the upper arms on the bench close to the head.
Extend the elbows to press the bar out in an arc until the arms are straight and parallel to the floor.
Squeeze the triceps for a second.
Bend the elbows to let the bar return toward the pulley under control.
Breathing: Exhale as you extend, inhale as the bar returns.
Upper arms glued to the bench
Elbows in
Full lockout
Lifting the upper arms off the bench
Rocking the hips to move the weight
Flaring the elbows
Use a pad under the knees and let the stack settle before standing up.