If your fitness goal is to up the ante on endurance, pack more power into your sprint, or supercharge your strength gains in the gym, it’s worth exploring – what are the different muscle fiber types?

Everyone is familiar, at least hand-wavingly, with the distinction between slow-twitch and fast-twitch muscle-fiber types. The former are great for running marathons; the latter are ideal for ...

slow-twitch muscle fibers, which move more slowly but help to keep you moving longer fast-twitch muscle fibers, which help you move faster, but for shorter periods “Twitch” refers to the contraction, ...

More mileage during training results in faster finish times, right? Recent research suggests that might be true for some runners—but not for everyone. Before and immediately after each training period ...

Most fitness-minded people have probably heard of fast- and slow-twitch muscle fibers. However, the distinction can be somewhat mysterious, especially in the context of understanding how it relates to ...

Tsukuba, Japan—Different types of exercise encourage the formation of different types of muscle fibers, or the cells that make up your muscles. Slow twitch muscle fibers support endurance activities ...

When you picture different athletes—marathon runners, gymnasts, and Olympic weightlifters, for example—you likely categorize them instinctively by their height, size, and build. But the differences in ...

TOOLBOX: “We’re all individuals” shouted the mob outside Brian’s window in the Monty Python classic ‘Life of Brian’. Nowhere is that truer than in how athletes respond to training. Two riders may look ...

There's a lot of talk about lean muscle compared to bulk muscle, but experts say it's not worth differentiating the two. Learn why.