Your body is composed of more than 600 muscles, and even after discounting the ones that aren't visible, you're still left with more than 10 muscle groups that demand your attention in the gym. Understandably, when time is short, the smaller muscle groups get bypassed in favor of the larger, more visible ones. Understandable, but not advisable.
Let's take shoulders as a good example. While small in size, your shoulders are incredibly complex. Consisting of three distinct sections-front, side and rear--this ball-and-socket structure is the vertex of all upper-body activity. Want to work your chest from different angles? Your shoulders determine which angle. Want to hit your upper back? Your shoulders control exactly which area. Want to enhance your V shape? Build out those shoulders. So it makes good sense to allot some time to developing this small yet vital muscle group.
Next time you find yourself with only five minutes left at the gym, and you feel there's nothing constructive that can be accomplished, give this no-hassle, one-move shoulder workout a try. You'll be pleasantly surprised how much of a burn and pump you can get in those 300