In 2016, Justin Lippert bought a bike off Craigslist and competed in his first triathlon. Three years later, he's won five national championships, mostly wearing nothing but a smile and a pink watermelon Speedo. On the surface, he's a bit of a caricature: half-naked, tan, muscled with a handlebar mustache and backward trucker hat. His voracious joy is palpable via social media posts peppered with bro-isms like "stoked," "yeet," "gnarly" and "hype." He radiates equal parts silly, giddy and cocky.