Stand with feet at shoulder-width apart, holding a dumbbell in a neutral grip in each hand by your sides.
While holding your upper arm stationary, curl the weights towards your shoulders while rotating your hands so that the palms are facing up.
Once your biceps are fully contracted, hold and squeeze it, then return it back to the starting position. Repeat for desired amount of reps.
Model: Nichelle Laus; Photo credit: Dave Laus