LOS ANGELES — It took months of training and endless plates of protein to transform former ballerina Alicia Vikander into musclebound action hero Lara Croft for the new “Tomb Raider” film. The 29-year-old Oscar winner spent seven months working with Swedish trainer and nutritionist Magnus Lygdback, who also helped Ben Affleck get into superhero shape for “Justice League” and is helping Gal Gadot train for the upcoming “Wonder Woman” sequel. Lygdback and his team of fitness professionals hosted a boot camp in Los Angeles recently to demonstrate Vikander’s “Tomb Raider” training regimen. “Physically, anyone can train to be a superhero,” Lygdback said. Diet is paramount, even more than physical training, he said.