Strong ankles have always been important to ball/agility/cutting sports.
(Rolling an ankle can put you out for weeks.)
As there is more and more research coming out on this we are learning how much a strong ankle/foot/toes are a major contributor to injury and injury prevention for runners. This then contributes to faster paces and stronger frame.
I am a big believe in the "bottom up" approach.
3 exercises to get started:
1) Heel raise to toe raise - master both legs then move to single legs
2) Pogo jumps - up & down, front to back, side to side - make it fun!
3) Single leg square jumps - hop from corner to corner - do it slow for a balance component or fast for explosive - either way it helps the plantar fascia!
Give it a try and let me know how you do!