To perform this support yourself on a workout bench with one
knee and one hand. With the other hand lift a dumbbell from
the floor to your side, until your upper arm is just beyond horizontal
or at the height of your back. This is then lowered until your arm is
extended and shoulder stretched forward.
A variation of this exercise can be performed using a barbell, by
bending forward and pulling the barbell towards the chest. Keep your
knees slightly bent and look forwards during lifting to ensure good
form.