Does anyone know how to isolate a particular side, or more specifically a certain abdominal muscle with a workout? I've been trying for a long time to get a full 8 pack, but the lower left (when i look down, my left) abdominal muscle just isn't showing up as much as the right.. It's just the very bottom left one, and im thinking any lower ab workouts would help, but the right just seems to stay larger than the left.