Target selection is a crucial task in augmented reality (AR). Recent evidence suggests that user motion can significantly influence target selection. However, no systematic research has been conducted on target selection within varied intensity user motions and AR settings. This paper was carried out to investigate the effects of four user motions (i.e., standing, walking, running, and jumping) and two viewing modes (i.e., viewpoint-dependent and viewpoint-independent) on user performance of target selection in AR. Two typical selection techniques (i.e., virtual hand and ray-casting) were utilized for short-range and long-range selection tasks, respectively. Our results indicate that the target selection performance decreased as the intensity of user motion increased, and users demonstrated better performance in the viewpoint-independent mode than in the viewpoint-dependent mode. We also observed that users took a longer amount of time to select targets when using the ray-casting technique than the virtual hand technique. We conclude with a set of design guidelines to improve the AR target selection performance of users while in motion.