Think of swimming 50 yards underwater at the swim pool on one breath and that is a 75 foot free dive. The difference is if you come up short in a pool, you lift your head up. In a vertical dive no other option but to make it all the way. Not many swimmers can make that swim. Even with the aid of fins, the dive is impressive. I did hear PADI has a certification for free diving. Crazy. I thought you just had to practice and get in to swimming shape to free dive. I doubt if many divers could swim 25 yards underwater, thats why SCUBA was invented.