Better Sprinting Mod for Minecraft 1.9.4 Mods can makes it possible for you to bind sprinting to a key. One of its great advantages isthat it’s compatible with most mods that change options, like Optifine! Only incompatibilities are with mods, that change behavior of player entity or Controls menu (adding new buttons using GameSettings will work, changing like, way Controls menu works/looks won’t – it’ll break saving settings).
Download link: Better Sprinting Mod for Minecraft 1.9.4/1.8.9
Read more: Minecraft 1.9.4 Mods