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 ...

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 ...

Your DNA might be giving you an edge or could be holding you back. The ACTN3 gene encodes the protein alpha-actinin-3, which is found almost exclusively in fast-twitch muscle fibers. These fibers are ...

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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 ...