sentences:  An experienced martial artist from a young age, Markham began training in Shidokan Karate at the age of six before later transitioning into Kenpo.At the age of 13, Markham began training in Kyokushin and began fighting in full-contact competitions when he was 15, winning all of his matches by knockout despite often being paired against much older opponents.Markham also began competing in boxing at the age of 17, holding an undefeated amateur record of 10-0.