PREVIEW: Billy Monger - Changing Gear, Channel 4

Presenter, racing driver and double amputee, Billy Monger immerses himself in the world of Paralympic sport. This involves taking on one of the biggest challenges of his life: learning to run again.

With the Tokyo Paralympics on the horizon, this documentary sees Billy training alongside some of Britain's Paralympic stars, as he gains an understanding of what it takes to become an elite Paralympic athlete.

Billy swims in open water with Alice Tai and canoes with Charlotte Henshaw. He is also fitted with his very first running blades and, under the guidance of Paralympic legend Jonnie Peacock, attempts to sprint for the very first time.

In this powerful, insightful and often amusing film, Billy throws himself wholeheartedly into the sports, ending with an emotional run at Donnington, the location where, exactly four years ago, Billy lost his legs in a driving accident.

Airs Saturday on Channel 4.