When you picture different athletes – marathon runners, gymnasts and Olympic weightlifters, for example – you likely categorise them instinctively by their height, size and build. But what makes these ...

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 ...

What's the first thing that comes to mind when you think about the words twitch and muscle? Spasms, perhaps. You'd hardly be alone in thinking that. But when it comes to fitness, it's most commonly ...

Type IIb fast-twitch myofibers, known for their rapid contraction speed, are plentiful in small mammals but have largely diminished in humans. Researchers at the University of Tsukuba have discovered ...

Tsukuba, Japan—Muscle fibers, which constitute skeletal muscle, are classified into two main types: slow-twitch (Type I, red muscle) and fast-twitch (Type II, white muscle). Slow-twitch fibers are ...

Here’s how to level-up your run routine.

Women's Health may earn commission from the links on this page, but we only feature products we believe in. Why Trust Us? You’ve been training consistently—but some muscles seem to respond right away, ...

Your muscles aren’t just for lifting heavy objects and looking good in photos—they’re actually functioning as a sophisticated chemical factory that produces brain-boosting compounds essential for ...

A few years back, Golf Digest Best Young Teacher Steve Buzza (above) authored a terrific article on techniques that boost swing speed. His message is to give it all you got when you swing the driver.