Sporty sisters Maria and Valery Bystritskii may look innocent - but they're actually boy-beating cage fighters. The pair, aged just 11 and 10, enjoy gymnastics, painting and skiing like normal kids, but can also punch, grapple and submit opponents using slick mixed-martial arts manoeuvres. Both are students at Bunny's Gym in Winchester, Tennessee, where children as young as four are taught mixed martial arts or MMA, the sport popularised by the Ultimate Fighting Championship.

Videographer / Director: Mike Saliba
Producer: John Balson, Nick Johnson
Editor: Sonia Estal