After a grueling CrossFit workout on a hot Summer morning that involved kettlebell swings, goblet squats, and about 100 walking lunges, my lower body was toast. But what was weird was that my left ...

While sitting still at your desk or watching TV, you sense a feeling of muscular discomfort in your arm or leg. It’s not quite a charley horse, but you can see your skin pulsating involuntarily, as if ...

Building your fast-twitch muscle fibers can help you get stronger and faster. This type of muscle fiber is responsible for the fast, explosive movements used in activities like sprinting, jumping, and ...

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 difference between slow twitch and fast twitch muscle fibers? The pros explain what they are, and why you should be working both. Your body is made up of two kinds of muscle fibers: slow ...