Playing the clarinet for many hours can cause anything from discomfort to serious chronical pain.
Traditional, the handpiece is about 12mm / ½inch above the position of the index finger. Here is the center of gravity of the instrument. You can turn it in any direction without effort.
Unfortunately, this often forces the hand into an uncomfortable position. To demonstrate this, simply let your hand hang down in a relaxed manner. Now your thumb and forefinger are exactly opposite. Now, as you move your thumb over your middle finger, feel the tension in your forearm.
When you stretch a muscle for a long time and maintain that position, you are doing a static job and creating a static tension. Blood is transported to the muscle, it burns the energy and waste products remain there so to speak. If the muscle were moved, the waste products could be washed away. Since this is not the case, your hand or forearm will eventually begin to hurt.
However, if you could keep your thumb at index finger height, the tension would be largely eliminated. In order to do this on the instrument, the hand rest has to be moved approx. 12mm/½inch upwards. This is a quick procedure and can eliminate many pains.
When moving the hand rest up, however, the center of gravity is also relocated. The instrument is now heavy on the bell side, which means that it wants to tip forward. To counteract this, we have developed the LP-Ballance barrels. The higher weight on the upper piece restores balance. Despite the added overall weight, the instrument is now more relaxed.
Alternatively, there are various special hand supports, which allow you to distribute the weight on larger thumb rest or on the palm. Many of them are adjustable in height or have an additional spacer plate. This is especially pleasant for big hands or very thin instruments. (Picture)
Should the jokes become chronic, one may also consider a specially made instrument holder. The instrument is supported on the body or ground.