Olympic boxing champ Claressa Shields' secret? Hard work and a stellar 5-punch combo

/ Source: TODAY

Claressa Shields became the first U.S. woman to win a boxing gold medal at the London Olympic Games in 2012. Now she’s going for her second gold in Rio and she tells TODAY’s Jenna Bush Hager that she’s happiest when she’s at the gym training. She also shows off her favorite 5-punch combination.