Conor McGregor is a prominent and successful professional mixed martial artist. However, he does not have visible six packs. This is likely because he prioritizes training for strength, speed, and skill over training solely for visible muscle definition. McGregor’s focus may also have to do with his desired weight class for competing in professional MMA fights. Working out to get defined abdominal muscles would require gaining weight, which could make him too heavy for the division he competes in.