Whether it’s Brad Pitt’s shredded frame in Fight Club or Henry Cavill getting superhero-jacked for Man of Steel and Batman v Superman, fans are obsessed with celebrity fitness transformations—and Justin Hartley is no exception. For years, Hartley has made a name for himself in roles that showcase his physique. In This Is Us, he plays Kevin Pearson, the athletic, spotlight-chasing “eldest” Pearson triplet known for his ripped build and football roots. In Netflix’s Senior Year, he takes on the role of Blaine Balboa...