Stan, good evening I hope you are well and having a great night. With regard to your question, consider the following. The elbow joint will be used in most all upper body exercises and movements. A common injury is tendinitis felt on the back of the elbow. While most think it is their elbow hurting, it is in reality the tendons from their hands, due to poor grip. Most people assume that this is their tricep tendon. Most likely, it is the tendon from the wrist flexor muscles. This set of muscles originates from the rear side of the elbow (medial epicondyle of the humerus) and insert onto the fingers in different arrangements. During lying tricep extensions some will allow their wrist to be bent backwards. This will cause stress and chronic pain to the backside of the elbow. This can be fixed by maintaining a strong grip on the bar and keeping your wrist flexed or stiffened. Remember to keep a firm and correct grip on the bar to help minimize potential pain.