Health and medicine: Type 1 and type 2 muscle fibers

Skeletal muscle fibers can be categorized into two types: slow-twitch (Type I) and fast-twitch (Type II). Type I muscle fibers are more efficient over long periods of time. They are mainly used for postural maintenance (such has holding the head upright), or endurance exercises (like marathon running). Type II muscle fibers use anaerobic respiration and are better for short bursts of speed than Type I fibers, although they fatigue more quickly.

Health and medicine

The medical world can be a confusing place. Patients, their families, and even students entering health fields might feel overwhelmed by the large vocabularies and complicated explanations. We hope to make understanding the medical world a bit easier. Look around! These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read or seen in any Khan Academy video.

Muscular system introduction

Muscles never sleep (literally). If you have ever taken a breath, you have benefited from the work of the diaphragm, which contracts to create an area of low pressure within your thoracic cavity, allowing air in. How exactly are some weightlifters able to support 717 lbs without breaking anything more than a little sweat? Fun fact: the largest muscle in your body is the gluteus maximus (that’s your butt) while the smallest skeletal muscle is the stapedius (it stabilizes the smallest bone, the stapes, which is in your middle ear).

Topic: Science

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