A majority of orthopedic injuries that occur in the gym happen because the weight being moved isn’t being controlled by the joint and muscle through the eccentric (negative) phase of the contraction. In other words, people get hurt during exercise when they don’t control the weight throughout the whole of the movement.
Sets, reps and intensity are often thought of as the primary factors that dictate results. While they are a huge part of what will happen to your physique it is also a few other principles such as pace of movement (how fast you are moving), range of motion (amount of extension and flexion on the joint) and path of motion (the line the exercise in being performed through) that allow you to stay injury free to lift another day and also to accelerate those results.
There are several correct ways to perform a general exercise but OUT OF CONTROL is always wrong.