Nagata, A, Doma, K, Yamashita, D, Hasegawa, H, and Mori, S. The effect of augmented feedback type and frequency on velocity-based training-induced adaptation and retention. J Strength Cond Res 34(11): 3110-3117, 2020-The purpose of this study was to compare the benefits of 4 weeks of velocity-based training (VBT) using different augmented feedback (AugFb) types and the frequency of AugFb, and whether adaptations are retained 10 days post-training. Thirty-seven collegiate male rugby players were divided into groups that received immediate feedback (ImFb; n = 9), visual feedback (ViFb; n = 10), average feedback (AvgFb; n = 10) and no feedback (NoFb; n = 8) during each VBT session consisting of 3 sets of 5 repetitions of loaded jump squats. The ImFb group received AugFb regarding lifting velocity under loaded jump squats (LV-JS) after every jump, whereas LV-JS measures were averaged after each set of jumps and presented to the AvgFb group. The LV-JS were video-recorded and displayed as kinematic feedback for the ViFb group after each set, although NoFb was provided for the NoFb group. Loaded jump squats measures were reported at baseline, during each training session and 10 days post-training. Loaded jump squats measures were significantly greater for the ImFb Group compared with the other groups during a number of post-baseline time points (p ≤ 0.05). Furthermore, at 4 weeks of VBT and 10 days post-retention, effect size (ES) calculations showed that LV-JS measures were greater with moderate to large effects for the ImFb group compared with the NoFb (ES = 1.02-1.25), AvgFb (ES = 0.78-0.82) and ViFb (ES = 0.74-1.60), respectively. However, LV-JS measures were reduced with moderate to large effects 10 days post-retention for the ViFb (ES = -0.60) and NoFb (ES = -0.85) groups. Providing LV-JS feedback after each jump appears to optimize performance and should be considered as a training tool during VBT.