Genetics and Muscle Fiber Training

Your genetics largely decide if you're a natural sprinter or a marathon runner, but you can still

change the game. It all comes down to your muscle fibers. You have slow-twitch fibers for endurance,

fueled by oxygen, and fast-twitch fibers for explosive power that burn out quickly.

Your DNA sets your natural ratio of these. But here’s the twist: training can shift

this ratio by up to 10%. Endurance workouts build more slow-twitch fibers,

while strength training boosts your fast-twitch ones. So, while genetics give

you a head start, your hard work literally reshapes your muscles from the inside out.