If you didn’t already know you have different types of muscle fibers in your body, now you do. And depending on how you exercise or what sports you enjoy, you’re building and recruiting some ...

Fitness experts share which muscles running works and answer the age-old question: Does running count as leg day?

Former NFL pro Roman Fortin is helping his clients strengthen their "Fast Twitch" muscles—the muscle fibers we use when doing short, intense—more exertive activity. Problem is these types of ...

Another thing that can influence how well you put on muscle are your fast-twitch and slow-twitch muscle fibers. Skeletal muscles are composed of both of these fibers, which serve different ...

Muscle fibers come in two main varieties called fast-twitch and slow-twitch that most of us possess in roughly equal measures. Fast-twitch fibers build more muscle mass and produce most of the sudden ...

Chimps possess about twice the amount of "fast-twitch" muscle fibre. This type of fibre contracts quickly and is useful for rapid movements such as sprinting. But fast-twitch fibres have a ...

The size and length of your tendons and the makeup of your muscle fibers affect your abs, too, and these are things you can’t change. “Some people have more fast-twitch muscle fibers ...