WEB: BLOG: ... What is wrong with Joe Six-Pack's eyes? Seriously... what's wrong with him?? On all single-joint exercise machines, it is important to keep the axis of rotation of the machine in alignment with the axis of rotation of the body part being moved. In this example, the elbow joint should be kept in line with the Triceps Extensions machine. For all of the secrets of fitness, please visit Sign up for your FREE Newsletter and your FREE 7-DAY FULL ACCESS WEBSITE MEMBERSHIP.