scoreboard players tag @a[tag=InGame] add ActivateSpeedPowerup {Inventory:[{Slot:100b,id:"minecraft:diamond_boots"}]}
replaceitem entity @a[tag=InGame] slot.armor.feet air
effect @a[tag=ActivateSpeedPowerup] speed 5 4 true
scoreboard players tag @a[tag=ActivateSpeedPowerup] remove ActivateSpeedPowerup