How Did Training Change One Identical Twin's Muscles?

On Huberman Lab, the limits of physiological adaptation are darn near boundless given enough exposure. After 35 years of extremely consistent training, one identical twin's muscle morphology was completely different than his identical twin with the exact same DNA.

Two examples cover people doing endurance work for a number of years and the benefits and functionality that work gives them. On the question of whether the opposite experiment has been done or observed, where somebody just weight lifted or just sprinted for a number of years, On Huberman Lab, it is not known that an identical twin control exists. The expectation stated on Huberman Lab is that the person who sprints or does heavy squats and explosive work would then have more fast-twitch muscle fibers in the quad, and the non-exercising counterpart would have fewer.

The show states outright that the specific data on endurance level in somebody who has just done strength training or just sprinted are not available. Studies on lifelong strength trainers are only starting to come out. There are not a lot of people who have been lifting weights for thirty plus years, while a whole swath of people have been doing endurance training for that long.