Rapidly resetting your sprint by tapping your "W" or "S" keys changes your horizontal acceleration vector. Doing this at the precise moment of impact minimizes your backward travel.
Rather than downloading individual .jar files from random websites, the safest way to use Anti-KB features is through recognized clients or open-source mods. 1. Trusted PvP Clients anti kb mod 189 verified
Once in-game, you can often configure the mod using command-line arguments: /kb [min_kb] [max_kb] [chance] Rapidly resetting your sprint by tapping your "W"