Radnor, JM, Lloyd, RS, and Oliver, JL. Individual response to different forms of resistance training in school-aged boys. J Strength Cond Res 31(3): 787–797, 2017—The aim of this study was to examine individual responses to different forms of resistance training on measures of jumping and sprinting performance in school-aged boys. Eighty boys were categorized into 2 maturity groups (pre- or post–peak height velocity [PHV]) and randomly assigned to a plyometric training, resistance training, combined training, or control group. Intervention groups participated in training twice weekly for 6 weeks, with measures of acceleration, maximal running velocity, squat jump height, and reactive strength index (RSI) collected preintervention and postintervention. In the pre-PHV cohort, plyometric training and combined training resulted in significantly more positive responders than the other 2 groups in both sprint variables (standardized residual values >1.96). In the post-PHV cohort, significantly more positive responders for acceleration and squat jump height resulted from traditional strength training and combined training groups, compared with other groups. Conversely, plyometric training and combined training resulted in a significantly greater number of positive responders than the other 2 groups for maximal velocity and RSI. Control participants rarely demonstrated meaningful changes in performance over the 6-week period. Irrespective of maturation, it would seem that combined training provides the greatest opportunity for most individuals to make short-term improvements in jump and sprint performance. Taking maturation into account, our data show that a plyometric training stimulus is important for individuals in the pre-PHV stage of development, whether as a stand-alone method or in combination with traditional strength training, when attempting to improve jumping and sprinting ability. However, individuals in the post-PHV stage require a more specific training stimulus depending on the performance variable that is being targeted for improvement.