{"id":28524,"date":"2026-07-27T11:13:52","date_gmt":"2026-07-27T18:13:52","guid":{"rendered":"https:\/\/dornsife.usc.edu\/news\/?p=28524"},"modified":"2026-07-27T11:19:50","modified_gmt":"2026-07-27T18:19:50","slug":"what-makes-muscles-contract-physiologist-explains-how-muscles-move","status":"publish","type":"post","link":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/","title":{"rendered":"What makes muscles contract? A physiologist explains how muscles\u00a0move"},"content":{"rendered":"\n\n\n    \n                                \n\n  \n    \n\n\n\n\n\n\n<div\n  class=\"cc--component-container cc--article-hero \"\n\n  \n  \n  \n  \n  \n  \n  >\n  <div class=\"c--component c--article-hero\"\n    \n      >\n\n    \n<div class=\"inner-wrapper\">\n          \n<div class=\"f--field f--image\">\n\n    \n    \n    \n    \n    \n    \n              \n      <img\n                            data-src=\"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-flex-2000x1150-1-768x432.jpg\"\n          data-srcset=\"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-flex-2000x1150-1-1920x1080.jpg 1920w,https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-flex-2000x1150-1-1280x720.jpg 1280w,https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-flex-2000x1150-1-768x432.jpg 768w\"          data-sizes=\"(min-width:1200px) 75vw, (min-width:768px) 83vw, 100vw\"          class=\"lazyload\"\n        \n                  alt=\"Old black-and-white photo of man facing away with arms raised flexing muscles\"\n        \n        \n                                      \/>\n\n    \n    \n  \n  \n\n<\/div>\n  \n      <div class=\"image-caption\">\n          \n<div class=\"f--field f--description\">\n\n    \n  A lot goes into making sure your muscles can move your body. (Image source: Rawpixel\/Public domain.)\n\n\n<\/div>\n    <\/div>\n  \n  <div class=\"text-wrapper\">\n          <nav aria-label=\"Breadcrumb\" class=\"breadcrumbs\">\n        <ul>\n                      <li><a href=\"\/news\/stories\/\">News<\/a><\/li>\n                      <li><a href=\"\/news\/stories\/\/?category=science-and-technology\">Science and Technology<\/a><\/li>\n                  <\/ul>\n      <\/nav>\n    \n              \n<div class=\"f--field f--page-title\">\n\n    \n  <h1>What makes muscles contract? A physiologist explains how muscles\u00a0move<\/h1>\n\n\n<\/div>\n    \n          <div class=\"subtitle\">\n            \n<div class=\"f--field f--description\">\n\n    \n  As part of The Conversations\u2019 \u201cCurious Kids\u201d series, USC Dornsife\u2019s Kiki Crawford describes how an entire team of electricity, calcium, energy and proteins all work together to move your muscles.\n\n\n<\/div>\n      <\/div>\n    \n           <strong class=\"author-field\"><span >By<\/span><a href=\"mailto:communication@dornsife.usc.edu\">Kiki Crawford<\/a><\/strong>\n    \n          <span class=\"post-date-field\">July 27, 2026<\/span>\n      <\/div>\n<\/div>\n\n\n  <\/div><\/div>\n\n  \n    \n\n\n\n\n\n\n<div\n  class=\"cc--component-container cc--social-share \"\n\n  \n  \n  \n  \n  \n  \n  >\n  <div class=\"c--component c--social-share\"\n    \n      >\n\n    \n  <div class=\"content-wrapper\">\n    <span class=\"a2a_kit a2a_kit_size_32 addtoany_list\" style=\"line-height: 32px;\">\n      <span class=\"title\">\n        Share\n      <\/span>\n                        <a class=\"a2a_button_copy_link\" target=\"_blank\" href=\"\/#copy_link\" rel=\"nofollow noopener\" title=\"Link\">\n            <span class=\"a2a_svg a2a_s__default a2a_s_copy_link\">\n              <svg height=\"19\" viewBox=\"0 0 19 19\" width=\"19\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"m7.43475275 9.52380952-2.17490843 2.26076008c-1.08745421 1.058837-1.68841575 2.518315-1.68841575 4.0350275 0 1.5167124.60096154 2.9475732 1.68841575 4.0350274 1.058837 1.0874543 2.51831502 1.6884158 4.03502747 1.6884158 1.44087681 0 2.80427251-.5423678 3.86936601-1.5289606l.1656615-.1594552 2.2321428-2.2321428-1.6311813-1.6311813-2.2321429 2.26076c-.6581959.658196-1.5167124 1.0016026-2.43246332 1.0016026s-1.7742674-.3434066-2.43246337-1.0016026c-.65819597-.6581959-1.00160257-1.5167124-1.00160257-2.4324633 0-.8547009.2991453-1.6595442.87416905-2.2981957l.12743352-.1342677 2.23214286-2.2321429zm6.88661855-.40736607-5.26116068 5.26116075 1.61881868 1.6188186 5.2611607-5.2611607zm1.3837569-5.54501488c-1.4408768 0-2.8042725.54236779-3.869366 1.52896062l-.1656615.15945513-2.23214282 2.23214286 1.63118132 1.63118132 2.2321429-2.23214286c.6581959-.65819597 1.5167124-1.00160256 2.4324633-1.00160256s1.7742674.34340659 2.4324634 1.00160256 1.0016026 1.51671246 1.0016026 2.43246337c0 .85470089-.2991453 1.65954419-.8741691 2.29819559l-.1274335.1342678-2.2321429 2.2321428 1.5739469 1.5739469 2.2321429-2.2321428c1.0874542-1.058837 1.6884157-2.5183151 1.6884157-4.03502751 0-1.51671245-.6009615-2.94757326-1.6884157-4.03502747-1.058837-1.08745421-2.518315-1.68841575-4.0350275-1.68841575z\" transform=\"translate(-3 -3)\"\/><\/svg>\n            <\/span>\n            <span class=\"a2a_label visually-hidden\">Copy Link<\/span>\n          <\/a>\n                                <a class=\"a2a_button_facebook\" target=\"_blank\" href=\"\/#facebook\" rel=\"nofollow noopener\" title=\"Facebook\">\n            <span class=\"a2a_svg a2a_s__default a2a_s_facebook\">\n              <svg height=\"19\" viewBox=\"0 0 19 19\" width=\"19\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"m23.9512 6h-16.9024c-.57923625 0-1.0488.46956375-1.0488 1.0488v16.9024c0 .5792362.46956375 1.0488 1.0488 1.0488h9.10024v-7.34768h-2.46772v-2.87584h2.46772v-2.11508c0-2.45404 1.49872-3.79012 3.68828-3.79012.7389668-.00263323 1.4775241.03516995 2.21236.11324v2.56348h-1.51392c-1.18788 0-1.4174.56544-1.4174 1.39612v1.8316h2.84772l-.37088 2.87584h-2.47684v7.34844h4.83284c.5792362 0 1.0488-.4695638 1.0488-1.0488v-16.9024c0-.57923625-.4695638-1.0488-1.0488-1.0488z\" fill-rule=\"evenodd\" transform=\"translate(-6 -6)\"\/><\/svg>\n            <\/span>\n            <span class=\"a2a_label visually-hidden\">Facebook<\/span>\n          <\/a>\n                                <a class=\"a2a_button_twitter\" target=\"_blank\" href=\"\/#twitter\" rel=\"nofollow noopener\" title=\"X\">\n            <span class=\"a2a_svg a2a_s__default a2a_s_twitter\">\n              <svg version=\"1.1\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" x=\"0px\"\n\t y=\"0px\" viewBox=\"0 0 30 30\" enable-background=\"new 0 0 30 30\" xml:space=\"preserve\" width=\"19\" height=\"19\">\n<path fill=\"#000\" fill-rule=\"evenodd\" clip-rule=\"evenodd\" d=\"M14.5,16.2l-0.8-1.1l-6.3-9h2.7l5.1,7.3l0.8,1.1\n\tl6.6,9.4h-2.7L14.5,16.2L14.5,16.2z M16.9,13.4l7.4-8.7h-1.8l-6.5,7.5L11,4.8H5l7.8,11.4L5,25.2h1.8l6.8-7.9l5.5,7.9h6L16.9,13.4\n\tL16.9,13.4z\"\/>\n<\/svg>\n\n            <\/span>\n            <span class=\"a2a_label visually-hidden\">X<\/span>\n          <\/a>\n                                <a class=\"a2a_button_linkedin\" target=\"_blank\" href=\"\/#linkedin\" rel=\"nofollow noopener\" title=\"Linkedin\">\n            <span class=\"a2a_svg a2a_s__default a2a_s_linkedin\">\n              <svg height=\"19\" viewBox=\"0 0 19 19\" width=\"19\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"m25 21.4220779c0 1.974026-1.6038961 3.5779221-3.5779221 3.5779221h-11.84415582c-1.97402598 0-3.57792208-1.6038961-3.57792208-3.5779221v-11.84415582c0-1.97402598 1.6038961-3.57792208 3.57792208-3.57792208h11.84415582c1.974026 0 3.5779221 1.6038961 3.5779221 3.57792208zm-14.5584416-12.21428569c-.98701295 0-1.60389606.61688311-1.60389606 1.48051949-.12337663.8636364.49350649 1.4805195 1.48051946 1.4805195.987013 0 1.6038961-.6168831 1.6038961-1.4805195 0-.86363638-.6168831-1.48051949-1.4805195-1.48051949zm1.3571429 12.70779219v-8.6363636h-2.83766234v8.6363636zm10.2402597 0v-4.9350649c0-2.5909091-1.3571428-3.8246753-3.3311688-3.8246753-1.4805195 0-2.0974026.8636363-2.4675325 1.4805194v-1.2337662h-2.8376623v8.6363636h2.8376623v-4.9350649c0-.2467532 0-.4935065.1233767-.7402597.1233766-.4935065.6168831-.987013 1.4805194-.987013.987013 0 1.4805195.7402597 1.4805195 1.974026v4.564935z\" transform=\"translate(-6 -6)\"\/><\/svg>\n            <\/span>\n            <span class=\"a2a_label visually-hidden\">LinkedIn<\/span>\n          <\/a>\n                                <a class=\"a2a_button_bluesky\" target=\"_blank\" href=\"\/#bluesky\" rel=\"nofollow noopener\" title=\"Bluesky\">\n            <span class=\"a2a_svg a2a_s__default a2a_s_bluesky\">\n              <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"50px\" height=\"50px\" viewBox=\"0 0 24 24\">\n                <path fill=\"#00000\" d=\"M12 10.8c-1.087-2.114-4.046-6.053-6.798-7.995C2.566.944 1.561 1.266.902 1.565C.139 1.908 0 3.08 0 3.768c0 .69.378 5.65.624 6.479c.815 2.736 3.713 3.66 6.383 3.364c.136-.02.275-.039.415-.056c-.138.022-.276.04-.415.056c-3.912.58-7.387 2.005-2.83 7.078c5.013 5.19 6.87-1.113 7.823-4.308c.953 3.195 2.05 9.271 7.733 4.308c4.267-4.308 1.172-6.498-2.74-7.078a8.741 8.741 0 0 1-.415-.056c.14.017.279.036.415.056c2.67.297 5.568-.628 6.383-3.364c.246-.828.624-5.79.624-6.478c0-.69-.139-1.861-.902-2.206c-.659-.298-1.664-.62-4.3 1.24C16.046 4.748 13.087 8.687 12 10.8\"  fill-rule=\"evenodd\" \/>\n              <\/svg>\n            <\/span>\n            <span class=\"a2a_label visually-hidden\">Bluesky<\/span>\n          <\/a>\n                                <a class=\"a2a_button_email\" target=\"_blank\" href=\"\/#email\" rel=\"nofollow noopener\" title=\"E-mail\">\n            <span class=\"a2a_svg a2a_s__default a2a_s_print\">\n              <svg height=\"12\" viewBox=\"0 0 18 12\" width=\"18\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"m8.14285714 9.42857143c-.17142857 0-.34285714 0-.51428571.08571428l7.28571427 6.34285719c.3428572.2571428.6857143.2571428.9428572 0l7.2857142-6.34285719c-.0857142-.08571428-.2571428-.08571428-.4285714-.08571428zm-1.28571428 1.11428567v.1714286 8.5714286c0 .6857143.6 1.2857143 1.28571428 1.2857143h14.57142856c.6857143 0 1.2857143-.6 1.2857143-1.2857143v-8.5714286c0-.0857143 0-.0857143 0-.1714286l-7.2 6.3428572c-.7714286.6857143-1.8857143.6857143-2.6571429 0z\" fill-rule=\"evenodd\" transform=\"translate(-6 -9)\"\/><\/svg>\n            <\/span>\n            <span class=\"a2a_label visually-hidden\">Email<\/span>\n          <\/a>\n                  <\/span>\n  <\/div>\n\n  <\/div><\/div>\n \n\n\n\n  \n    \n\n\n\n\n\n\n<div\n  class=\"cc--component-container cc--rich-text \"\n\n  \n  \n  \n  \n  \n  \n  >\n  <div class=\"c--component c--rich-text\"\n    \n      >\n\n    \n      \n<div class=\"f--field f--wysiwyg\">\n\n    \n  <blockquote><p><strong>What makes the cells of the muscles contract? \u2014 Samarth, age 13, India<\/strong><\/p><\/blockquote>\n<hr \/>\n<p>Muscles are amazing. They\u2019re what let you strum a guitar, kick a soccer ball and high-five your friends. When you decide to move, your brain tells your muscles what to do, and they spring into action. But what is actually happening inside your muscles to make that happen?<\/p>\n<p>To answer that question, you first need to understand how your muscles are put together.<\/p>\n<h2>What muscles are made of<\/h2>\n<p>Every muscle in your body <a href=\"https:\/\/training.seer.cancer.gov\/anatomy\/muscular\/structure.html\" target=\"_blank\" rel=\"noopener\">is an organ<\/a>, and just like every other organ, muscles are made of cells. Muscle cells, called <a href=\"https:\/\/www.healthline.com\/health\/muscle-fibers\">muscle fibers<\/a>, are shaped a little differently than most other cells. Muscle fibers are long and ropelike. They can stretch and shorten, kind of like a bungee cord.<\/p>\n<p>Each muscle contains a bunch of these fibers all lined up together, side by side, like a bag of dry spaghetti noodles. Some muscles are made of <a href=\"https:\/\/doi.org\/10.1016\/0022-510X(88)90132-3\" target=\"_blank\" rel=\"noopener\">hundreds of thousands<\/a> of fibers.<\/p>\n<p>The muscles that you use to move your body are called skeletal muscles because they move your bones. Each muscle is attached to bones by tendons. When a muscle shortens, it tugs on the tendon, which pulls on the bone, allowing you to move.<\/p>\n<h2>Microscopic rope pulls<\/h2>\n<figure id=\"attachment_28544\" aria-describedby=\"caption-attachment-28544\" style=\"width: 500px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-28544 size-medium\" src=\"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-arm-instory-500x411.jpg\" alt=\"Illustration of muscles and connective tissue in bent arm\" width=\"500\" height=\"411\" srcset=\"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-arm-instory-500x411.jpg 500w, https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-arm-instory.jpg 750w\" sizes=\"(max-width: 500px) 100vw, 500px\" \/><figcaption id=\"caption-attachment-28544\" class=\"wp-caption-text\">The muscles of the human arm at work. (Image source: Flickr\/National Institute of Arthritis and and Musculoskeletal and Skin Diseases, National Institutes of Health.)<\/figcaption><\/figure>\n<p>Your cells are filled with molecular machines made out of <a href=\"https:\/\/www.genome.gov\/genetics-glossary\/Protein\" target=\"_blank\" rel=\"noopener\">proteins<\/a>. They help your cells do their jobs.<\/p>\n<p><a href=\"https:\/\/www.britannica.com\/science\/actin\" target=\"_blank\" rel=\"noopener\">Actin<\/a> and <a href=\"https:\/\/www.britannica.com\/science\/myosin\" target=\"_blank\" rel=\"noopener\">myosin<\/a> are two proteins that are super important for muscle fibers. Actin is like a microscopic rope, and myosin is like a microscopic hand. When millions of tiny myosin hands grab onto actin ropes and pull at the same time, the muscle fiber gets shorter. Scientists say the muscle is contracting.<\/p>\n<p>Notice that the tiny hands can only pull on the ropes. They never push. That is why <a href=\"https:\/\/thehappyscientist.com\/content\/muscles-dont-push\" target=\"_blank\" rel=\"noopener\">muscles can only pull<\/a>.<\/p>\n<p>See for yourself. Go ahead and bend your elbow. That muscle on the inside of your upper arm is called your biceps. When it gets shorter, it pulls to bend your arm. Now straighten your arm out. That muscle on the back of your arm is called your triceps, and it is pulling to straighten your arm. No pushing necessary.<\/p>\n<h2>Sending the message to move<\/h2>\n<p>That\u2019s how muscles create movement, but those tiny myosin hands aren\u2019t pulling all the time. What tells them when to pull? The answer is your brain.<\/p>\n<p>Your brain and muscles communicate using electricity. When you decide to move, your brain generates an electrical signal it sends to your muscles. To reach your muscles, the signal travels down your spinal cord, then along nerves that connect to your muscle fibers.<\/p>\n<p>These signals travel at speeds of over <a href=\"https:\/\/doi.org\/10.1016\/j.pneurobio.2011.06.001\" target=\"_blank\" rel=\"noopener\">200 miles per hour<\/a>. They reach the muscles so quickly that movement feels almost immediate. Luckily, for common movements like walking or writing, the brain sends these signals automatically so you don\u2019t need to think about them.<\/p>\n<p>When an electrical signal reaches the muscle fibers, it tells tiny sacs full of calcium to open. When calcium is stuck in these sacs, the myosin hands cannot get ahold of the actin ropes. But when the calcium is released, it acts like a key and <a href=\"https:\/\/bio.libretexts.org\/Bookshelves\/Introductory_and_General_Biology\/General_Biology_(Boundless)\/38%3A_The_Musculoskeletal_System\/38.18%3A_Muscle_Contraction_and_Locomotion_-_Regulatory_Proteins\" target=\"_blank\" rel=\"noopener\">unblocks the actin<\/a> ropes so the myosin hands can grab on.<\/p>\n<p>Scientists call this calcium storage system the <a href=\"https:\/\/www.britannica.com\/science\/sarcoplasmic-reticulum\" target=\"_blank\" rel=\"noopener\">sarcoplasmic reticulum<\/a>.<\/p>\n<p>Once calcium lets the myosin hands grab the actin ropes, they still need energy to pull. That energy comes from a special <a href=\"https:\/\/www.britannica.com\/science\/adenosine-triphosphate\" target=\"_blank\" rel=\"noopener\">cellular fuel called ATP<\/a>. ATP is the main source of energy for all of the cells in your body. Your body uses the food you eat to make ATP, and ATP helps power your proteins so that cells can do their jobs.<\/p>\n<h2>Putting it all together<\/h2>\n<p>So, what makes muscles contract? It takes an entire team of electricity, calcium, ATP and proteins all working together.<\/p>\n<p>First, your brain sends an electrical signal to your muscle fibers. This causes calcium to be released in those fibers. Calcium lets myosin proteins grab onto actin proteins. <a href=\"https:\/\/opened.cuny.edu\/courseware\/lesson\/806\/student\/?section=4\" target=\"_blank\" rel=\"noopener\">ATP provides the energy<\/a> for myosin to pull. When millions of tiny pulls happen at the same time, your muscle shortens and creates movement.<\/p>\n<p>Next time you wave to a friend or scroll to another Curious Kids article, you\u2019ll know that thousands of muscle fibers and millions of microscopic proteins are working together to make it happen.<!-- Below is The Conversation's page counter tag. Please DO NOT REMOVE. --><!-- End of code. If you don't see any code above, please get new code from the Advanced tab after you click the republish button. The page counter does not collect any personal data. More info: https:\/\/theconversation.com\/republishing-guidelines --><\/p>\n<p><a href=\"https:\/\/theconversation.com\/profiles\/kiki-crawford-2691397\" target=\"_blank\" rel=\"noopener\">Kiki Crawford<\/a>, Lecturer of Biological Sciences, <em><a href=\"https:\/\/theconversation.com\/institutions\/usc-dornsife-college-of-letters-arts-and-sciences-2669\" target=\"_blank\" rel=\"noopener\">USC Dornsife College of Letters, Arts and Sciences<\/a><\/em><\/p>\n<p>This article is republished from <a href=\"https:\/\/theconversation.com\" target=\"_blank\" rel=\"noopener\">The Conversation<\/a> under a Creative Commons license. Read the <a href=\"https:\/\/theconversation.com\/what-makes-muscles-contract-a-physiologist-explains-how-muscles-move-283652\" target=\"_blank\" rel=\"noopener\">original article<\/a>.<\/p>\n\n\n\n<\/div>\n\n\n  <\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>As part of The Conversations\u2019 \u201cCurious Kids\u201d series, USC Dornsife\u2019s Kiki Crawford describes how an entire team of electricity, calcium, energy and proteins all work together to move your muscles.<\/p>\n","protected":false},"author":14,"featured_media":28527,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[16],"tags":[88,87,1970,83],"class_list":["post-28524","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-science-and-technology","tag-biological-sciences","tag-expert-viewpoint","tag-life-sciences","tag-the-conversation"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.2 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>What makes muscles contract? A physiologist explains how muscles\u00a0move<\/title>\n<meta name=\"description\" content=\"It takes an entire team of electricity, calcium, energy and proteins all working together to move your muscles\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"What makes muscles contract? A physiologist explains the process\" \/>\n<meta property=\"og:description\" content=\"It takes an entire team of electricity, calcium, energy and proteins all working together to move your muscles\" \/>\n<meta property=\"og:url\" content=\"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/\" \/>\n<meta property=\"og:site_name\" content=\"USC Dornsife News\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/uscdornsife\" \/>\n<meta property=\"article:published_time\" content=\"2026-07-27T18:13:52+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2026-07-27T18:19:50+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-flex-2000x1150-1.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"2000\" \/>\n\t<meta property=\"og:image:height\" content=\"1150\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"Darrin Joy\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@uscdornsife\" \/>\n<meta name=\"twitter:site\" content=\"@uscdornsife\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/\"},\"author\":{\"name\":\"Darrin Joy\",\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/#\\\/schema\\\/person\\\/851085523b73581e3387a7fc90cadb96\"},\"headline\":\"What makes muscles contract? A physiologist explains how muscles\u00a0move\",\"datePublished\":\"2026-07-27T18:13:52+00:00\",\"dateModified\":\"2026-07-27T18:19:50+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/\"},\"wordCount\":10,\"publisher\":{\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/#organization\"},\"image\":{\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/wp-content\\\/uploads\\\/sites\\\/7\\\/2026\\\/07\\\/crawford-muscles-flex-2000x1150-1.jpg\",\"keywords\":[\"biological sciences\",\"expert viewpoint\",\"life sciences\",\"the conversation\"],\"articleSection\":[\"Science and Technology\"],\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/\",\"url\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/\",\"name\":\"What makes muscles contract? A physiologist explains the process\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/wp-content\\\/uploads\\\/sites\\\/7\\\/2026\\\/07\\\/crawford-muscles-flex-2000x1150-1.jpg\",\"datePublished\":\"2026-07-27T18:13:52+00:00\",\"dateModified\":\"2026-07-27T18:19:50+00:00\",\"description\":\"It takes an entire team of electricity, calcium, energy and proteins all working together to move your muscles\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/#primaryimage\",\"url\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/wp-content\\\/uploads\\\/sites\\\/7\\\/2026\\\/07\\\/crawford-muscles-flex-2000x1150-1.jpg\",\"contentUrl\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/wp-content\\\/uploads\\\/sites\\\/7\\\/2026\\\/07\\\/crawford-muscles-flex-2000x1150-1.jpg\",\"width\":2000,\"height\":1150,\"caption\":\"Old black-and-white photo of man facing away with arms raised flexing muscles\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"What makes muscles contract? A physiologist explains how muscles\u00a0move\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/#website\",\"url\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/\",\"name\":\"USC Dornsife News\",\"description\":\"USC Dornsife news and events\",\"publisher\":{\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/#organization\",\"name\":\"USC Dornsife News\",\"url\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/wp-content\\\/uploads\\\/sites\\\/7\\\/2024\\\/01\\\/USC-Dornsife-Cardinal-Black-on-White-RGB.jpg\",\"contentUrl\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/wp-content\\\/uploads\\\/sites\\\/7\\\/2024\\\/01\\\/USC-Dornsife-Cardinal-Black-on-White-RGB.jpg\",\"width\":1000,\"height\":330,\"caption\":\"USC Dornsife News\"},\"image\":{\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/#\\\/schema\\\/logo\\\/image\\\/\"},\"sameAs\":[\"https:\\\/\\\/www.facebook.com\\\/uscdornsife\",\"https:\\\/\\\/x.com\\\/uscdornsife\",\"https:\\\/\\\/www.instagram.com\\\/uscdornsife\\\/\",\"https:\\\/\\\/www.youtube.com\\\/user\\\/USCCollege\",\"https:\\\/\\\/www.linkedin.com\\\/school\\\/uscdornsife\"]},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/#\\\/schema\\\/person\\\/851085523b73581e3387a7fc90cadb96\",\"name\":\"Darrin Joy\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/6146fe42c51c04a279975fc6b76b6dd8e0953f02c4c058e244e6f3e9220652b3?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/6146fe42c51c04a279975fc6b76b6dd8e0953f02c4c058e244e6f3e9220652b3?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/6146fe42c51c04a279975fc6b76b6dd8e0953f02c4c058e244e6f3e9220652b3?s=96&d=mm&r=g\",\"caption\":\"Darrin Joy\"},\"url\":\"https:\\\/\\\/dornsife.usc.edu\\\/news\\\/stories\\\/author\\\/darrinjo\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"What makes muscles contract? A physiologist explains how muscles\u00a0move","description":"It takes an entire team of electricity, calcium, energy and proteins all working together to move your muscles","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/","og_locale":"en_US","og_type":"article","og_title":"What makes muscles contract? A physiologist explains the process","og_description":"It takes an entire team of electricity, calcium, energy and proteins all working together to move your muscles","og_url":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/","og_site_name":"USC Dornsife News","article_publisher":"https:\/\/www.facebook.com\/uscdornsife","article_published_time":"2026-07-27T18:13:52+00:00","article_modified_time":"2026-07-27T18:19:50+00:00","og_image":[{"width":2000,"height":1150,"url":"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-flex-2000x1150-1.jpg","type":"image\/jpeg"}],"author":"Darrin Joy","twitter_card":"summary_large_image","twitter_creator":"@uscdornsife","twitter_site":"@uscdornsife","schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/#article","isPartOf":{"@id":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/"},"author":{"name":"Darrin Joy","@id":"https:\/\/dornsife.usc.edu\/news\/#\/schema\/person\/851085523b73581e3387a7fc90cadb96"},"headline":"What makes muscles contract? A physiologist explains how muscles\u00a0move","datePublished":"2026-07-27T18:13:52+00:00","dateModified":"2026-07-27T18:19:50+00:00","mainEntityOfPage":{"@id":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/"},"wordCount":10,"publisher":{"@id":"https:\/\/dornsife.usc.edu\/news\/#organization"},"image":{"@id":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/#primaryimage"},"thumbnailUrl":"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-flex-2000x1150-1.jpg","keywords":["biological sciences","expert viewpoint","life sciences","the conversation"],"articleSection":["Science and Technology"],"inLanguage":"en-US"},{"@type":"WebPage","@id":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/","url":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/","name":"What makes muscles contract? A physiologist explains the process","isPartOf":{"@id":"https:\/\/dornsife.usc.edu\/news\/#website"},"primaryImageOfPage":{"@id":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/#primaryimage"},"image":{"@id":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/#primaryimage"},"thumbnailUrl":"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-flex-2000x1150-1.jpg","datePublished":"2026-07-27T18:13:52+00:00","dateModified":"2026-07-27T18:19:50+00:00","description":"It takes an entire team of electricity, calcium, energy and proteins all working together to move your muscles","breadcrumb":{"@id":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/#primaryimage","url":"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-flex-2000x1150-1.jpg","contentUrl":"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2026\/07\/crawford-muscles-flex-2000x1150-1.jpg","width":2000,"height":1150,"caption":"Old black-and-white photo of man facing away with arms raised flexing muscles"},{"@type":"BreadcrumbList","@id":"https:\/\/dornsife.usc.edu\/news\/stories\/what-makes-muscles-contract-physiologist-explains-how-muscles-move\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/dornsife.usc.edu\/news\/"},{"@type":"ListItem","position":2,"name":"What makes muscles contract? A physiologist explains how muscles\u00a0move"}]},{"@type":"WebSite","@id":"https:\/\/dornsife.usc.edu\/news\/#website","url":"https:\/\/dornsife.usc.edu\/news\/","name":"USC Dornsife News","description":"USC Dornsife news and events","publisher":{"@id":"https:\/\/dornsife.usc.edu\/news\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/dornsife.usc.edu\/news\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/dornsife.usc.edu\/news\/#organization","name":"USC Dornsife News","url":"https:\/\/dornsife.usc.edu\/news\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/dornsife.usc.edu\/news\/#\/schema\/logo\/image\/","url":"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2024\/01\/USC-Dornsife-Cardinal-Black-on-White-RGB.jpg","contentUrl":"https:\/\/dornsife.usc.edu\/news\/wp-content\/uploads\/sites\/7\/2024\/01\/USC-Dornsife-Cardinal-Black-on-White-RGB.jpg","width":1000,"height":330,"caption":"USC Dornsife News"},"image":{"@id":"https:\/\/dornsife.usc.edu\/news\/#\/schema\/logo\/image\/"},"sameAs":["https:\/\/www.facebook.com\/uscdornsife","https:\/\/x.com\/uscdornsife","https:\/\/www.instagram.com\/uscdornsife\/","https:\/\/www.youtube.com\/user\/USCCollege","https:\/\/www.linkedin.com\/school\/uscdornsife"]},{"@type":"Person","@id":"https:\/\/dornsife.usc.edu\/news\/#\/schema\/person\/851085523b73581e3387a7fc90cadb96","name":"Darrin Joy","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/6146fe42c51c04a279975fc6b76b6dd8e0953f02c4c058e244e6f3e9220652b3?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/6146fe42c51c04a279975fc6b76b6dd8e0953f02c4c058e244e6f3e9220652b3?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/6146fe42c51c04a279975fc6b76b6dd8e0953f02c4c058e244e6f3e9220652b3?s=96&d=mm&r=g","caption":"Darrin Joy"},"url":"https:\/\/dornsife.usc.edu\/news\/stories\/author\/darrinjo\/"}]}},"_links":{"self":[{"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/posts\/28524","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/users\/14"}],"replies":[{"embeddable":true,"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/comments?post=28524"}],"version-history":[{"count":12,"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/posts\/28524\/revisions"}],"predecessor-version":[{"id":28554,"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/posts\/28524\/revisions\/28554"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/media\/28527"}],"wp:attachment":[{"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/media?parent=28524"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/categories?post=28524"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dornsife.usc.edu\/news\/wp-json\/wp\/v2\/tags?post=28524"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}