Move the weight slowly into full extension so you can squeeze and fully contract the triceps. Do not suddenly "lock out" your elbow, rather squeeze the motion until your elbows are straight.
• One arm dumbbell kickback supported on a bench, a rope pulley cable triceps extension, and an elastic tubing pulldown or kickback.
• If you have elbow problems, especially pain behind the elbow when you fully straighten your arm, then resist the temptation to fully lock out your elbows.
DB Kickback start
DB Kickback end