Gareth A Davies talks to Claressa Shields American professional boxer and mixed martial artist. Full of life and vigour world boxing champion Claressa Shields is enthusing about her venture into mixed martial arts, how a link-up with Mike Tyson was like “being with my long lost uncle” and that “beating up men” in sparring and indeed in the ring, such as Youtube sensation Jake Paul, is far from beyond the 26-year-old originally from Flint, Michigan.