Hirsch, SM, Chapman, CJ, Singh, H, Baker, DG, and Frost, DM. A critical appraisal of using barbell velocity data to regulate training. J Strength Cond Res 39(3): 360-372, 2025-Practitioners must balance numerous training variables to ensure they do not impose too much nor too little training stress on their athlete. As an athlete's capacity can fluctuate based on their preparedness for training, the intended vs. actual training intensity in a fixed training program may not coincide. Similarly, the training set volume that an athlete should be exposed to may fluctuate depending on their current state. A discrepancy between intended vs. actual training intensity and volume could negatively impact subsequent training adaptations. Thus, researchers and practitioners have advocated for "autoregulation," whereby the volume and intensity of training are automatically adjusted based on the athlete's preparedness. One proposed method of autoregulating resistance training is by using barbell velocity data. However, it is unclear whether, and under which contexts, these data are appropriate for regulating resistance training. Therefore, the purpose of this literature review was to critically examine the current research on using barbell velocity data to regulate resistance training intensity and volume. After examining the relevant literature, it is the authors' belief that the current data do not support using velocity data to precisely regulate resistance training intensity. However, it is the authors' belief that the current literature does suggest that researchers and practitioners can leverage these data to regulate other aspects of resistance training, such as athlete motivation, autonomy, and focus of attention, which could also impact the resulting adaptations from training. Overall, more research is required to better understand how researchers and practitioners should use velocity data to guide training.