Set a Smith machine bar at a comfortable height and stand with feet shoulder-width apart. Grip the bar with a narrow, palms-down (pronated) grip, hinge at the hips with a slight knee bend, and lower your torso until roughly parallel to the floor. Pull the bar toward your abdomen while squeezing your upper back, then lower it back down with control, keeping your core engaged and back straight throughout.
Log your smith bent over narrow pronated grip row sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.