Having trouble with your golf swing? Are you losing your balance with your hockey shot? What about a baseball swing or tennis swing? All sports require some sort of strength, balance, and coordination. For the rotational sports mentioned, dissociation of the upper body and lower body is a crucial requisite to help generate torque. However, dissociation requires balance and stability.
Before we focus on generating torque and power, we need to make sure we can dissociate the upper and lower body in a slow and controlled manner. Doing it this way requires active control using muscles. If we are not actively doing it during sports when it's happening fast, we are torquing passive structures. This can lead to excessive stress or strain, which can lead to injury. Here is a great drill to work on active dissociation.
1) First part of the video is practicing thoracic spine and upper body rotation on a stable pelvis.
2) Second part of the video is practicing hip and pelvis rotation with a stable torso.
This is a great drill specifically for golfers by performing this exercise in the golf address position. Do your best to keep the head and neck as still as possible. Be sure to breathe during the thoracic rotation!