There's an old espn article about how Giannis went from 6 "8" to 6 "11" and from like 190 to 220 in a year and a half
Found it
The extraordinary measures of Giannis Antetokounmpo
"When we first drafted Giannis, we measured him at 6-foot-8½," Bucks GM John Hammond says. But at midseason, the Bucks' strength and conditioning coach walked into Hammond's office. "He told me, 'The kid is still growing and I don't think he's done.'" By season's end, he was 6-11. Even more remarkable is that the basketball gods gifted Antetokounmpo those extra 2½ inches of height without exacting any payment. The 6-11 Giannis is every bit as stable and agile as the shorter version. If he remains at the small forward position, he'll do so as the tallest wing in the league.
Over the past 18 months, Antetokounmpo has put on an impressive amount of muscle-his weight went from 196 pounds on draft day to 222 this season. But, crucially, he's managed to do it without bulking up. "To be big is one thing, but to have muscles that are tuned to their optimal characteristics is another," says Troy Flanagan, Ph.D., the Bucks' director of performance. All that lean muscle mass allows him to generate force quickly, which gives him the agility and explosiveness that the NBA game demands.