PREPARATION
1.Stand with your left foot in
  front of your right foot, feet
  hip width apart.

2.Bend your knees and bend forward
  from the waist, supporting your
  body with your left hand on
  your left thigh.

3.Take a dumbbell in your right
  hand, palm facing inwards, and
  raise it to the front of your
  shoulder. Your elbow should be
  high and your upper arm close to
  your body. Breathe in.

EXERCISE
1.Keeping your elbow high, breathe
  out as you straighten your arm,
  pressing the weight out behind
  you.

2.Hold briefly, then breathe in as
  you return the weight to your
  shoulder.

Do not allow the dumbbell to swing
under it's own weight.

MAINLY FOR: Triceps

If you feel a strain in your
neck or back, try the exercise
"Tricep Kickback, Seated" as an
alternative.