While it may be a fact that the most common injury is the sprained ankle, I firmly believe that torn and otherwise tortured rotator cuffs check in at a close second. I have at least three clients and two people in my Circuit Sculpt class, and I have done countless orientations for people with some type of bum shoulder syndrome. (And no, "bum shoulder syndrome" is not a scientific term but I like it anyway.) Keep in mind that our shoulder joints give us the ability to move our arms here, there and everywhere which ultimately means they are our most flexible joints. Unfortunately, that also means they are extremely susceptible to injury.
So with all of those parts and pieces working together to move our arms every which way, you can imagine why the shoulder joint is so susceptible to injury. Things can get pinched, torn or just generally overused. Or something traumatic might happen to that specific area of our body. These things do happen and they're not fun, which is why it's a good idea to devote some time to your shoulders when you strength train. Specifically speaking, your rotator cuff muscles.
Try this: Grab a set of dumbbells, one in each hand. Bend your arms to 90 degrees, palms facing each other. Rotate the weights out to your side as if you were opening a jacket, taking care to keep your elbows and the upper part of your arms tight to your side. Return to start and repeat until you've completed your desired number of repetitions. (Note that this can also be done with a cable machine or an elastic band. You'll just have to do one arm at a time.)
Don't try this: upright rows, behind-the-neck pull-downs, over-head presses, dropping your elbows below your chest in a dumbbell bench fly or press, or raising your arms higher than 90 degrees in a shoulder abduction. All of which can put some major strain on your shoulder joints.
And always, always stretch your shoulders before and after you strength train to keep them as flexible as possible. Pull each arm across your chest. Hold on to each side of a door opening and gently lean forward. Just Google "shoulder stretches" and you'll find hundreds of options.
Hopefully you don't, but if at any point you begin to experience any type of shoulder pain...if it persists longer than a normal sore muscle would persist...I advise you to seek the help of a professional. Once again, your shoulder joint is widely used so you'll want to keep it as healthy as possible.
Question: What is your favorite shoulder exercise? Do you currently work your rotator cuff muscles as frequently as you do your delts? Or is that something you need to work on?