Body mechanics (posture in motion) is the ability to control body movement. Many discussions of posture are limited to static positions such as sitting and standing. Good posture during movement is imperative for efficiency and injury control. Just as good posture requires balanced alignment of the body, so does exercise. Many Soldiers use awkward movements as they struggle to perform one last repetition. When body mechanics are poor, the exercise serves little purpose and may do more harm than good. The activities in the PRT system were designed to reinforce proper body mechanics. Of special importance to PRT leaders are the checkpoints given for each exercise. Adherence to these checkpoints ensures optimal execution of the exercise. Over time, skillful movements become second nature to the Soldier. When this occurs, physical readiness is enhanced and injury risk is minimized.