Lie supine on a bench or the floor with a dumbbell in one hand and pressed straight up with the palm forward. Keeping the palm facing forward and the elbow out to the sides, bend the elbow to lower the dumbbell to the chest, then extend again to the top.
 
Purpose
The Tate press is a tricep exercise that emphasizes the medial head; the single-arm variation creates more space for the dumbbell to move and therefore allows the upper arm to remain more vertical than in a 2-arm Tate press.
 
Programming
Generally sets of 10-15 are appropriate.