from BODYBUILDING 101 by Robert Wolfe, Ph. D.:
"...he did them a number of ways: standing, seated, and with a twist (popularized by Arnold Schwarzenegger years ago). To do the Arnold press, he told us to keep the upper torso firmly erect and supported wiht either a bench or a blet to stabalize the shoulders.
Since this movement is more diffcult than regular dumbbell presses, John went a bit lighter on the weight. He always stated the exercise with his arms to his sides and palms facing in. As he pressed the weights up, he simultaneously turned his wrists until his palms faced forward. He cautioned us that elbow positioning is a bit tricky: keep the elbows pointing directly out to the sides and in line with the upper torso as the weight is raised; keep them pointing downward and never back or foreward when the weight is lowered. He did 6 to 12 reps per set."