There is also a special null type, the type of the expression null, which has no name. Because the null type has no name, it is impossible to declare a variable of the null type or to cast to the null type. The null reference is the only possible value of an expression of null type.
The military barbell press mainly works the shoulder, or deltoid, muscles. The anterior deltoid, the front head of the shoulder muscle, does much of the work. The side, or lateral, deltoid and the rear, or posterior, deltoid are also involved in the movement, although to a lesser degree than the anterior deltoid.
What Muscles Do Dumbbell Pullovers Work? A man is does a dumbbell pullover at the gym. Dumbbell pullovers are a bit of an exercise anomaly in that they work two opposing muscles simultaneously: the chest and the back muscles. The chest muscles are the primary movers, but several muscles of the back assist during the movement.