{"id":8284,"date":"2019-05-22T16:06:02","date_gmt":"2019-05-22T16:06:02","guid":{"rendered":"http:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/isotonic_contraction\/"},"modified":"2019-05-22T16:06:02","modified_gmt":"2019-05-22T16:06:02","slug":"isotonic_contraction","status":"publish","type":"post","link":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/isotonic_contraction\/","title":{"rendered":"Isotonic contraction"},"content":{"rendered":"<p>Generation of muscle shortening without an increase in tension. &nbsp;Thus, muscle length changes, but tension remains unchanged, with the resultant movement of a body part. &nbsp;Such a voluntary contraction of skeletal muscle, can only happen when the maximal force of contraction generated by a muscle is greater than the external force acting on the muscle. &nbsp;There are two types of isotonic contraction: concentric contractions in which the muscle shortens when it contracts, and as such they are the most common form of contraction in both daily and sporting activities; eccentric contractions are the opposite of concentric ones in that the muscle lengthens as it contracts, thus enabling the deceleration of a body part or object. &nbsp;An example of both contractions being involved in completing an action is provided in kicking a ball: the quadriceps muscle contracts concentrically to straighten the knee while the hamstrings contract eccentrically to decelerate the movement of lower leg. &nbsp;<a href=\"http:\/\/www.autourdavignoncoaching.com\/wp-content\/uploads\/2008\/12\/forceenfantphysician.pdf\" class=\"cc-route-enabled\" target=\"_self\" data-editable-link=\"http:\/\/www.autourdavignoncoaching.com\/wp-content\/uploads\/2008\/12\/forceenfantphysician.pdf&amp;target=_self\" rel=\"noopener noreferrer\">Strength training for children<\/a> and adolescents by means of isotonic contractions (as well as isometric contractions perhaps to a lesser extent) is topic of continuing debate. &nbsp;The difference between isotonic and isometric contractions is visually summarized in the figure below. &nbsp;<\/p>\n<p><img decoding=\"async\" src=\"..\/wp-content\/uploads\/2019\/05\/Isotonic-contraction2.jpg\" \/><\/div>\n<\/div>\n<p style=\"text-align: center;\" class=\"\">Isotonic compared with isometric contractions: a biceps curl does not involve a concentric contraction as the resistance does not remain the same throughout the movement. Consequently, it is more correctly referred to as an auxotonic contraction. What is not illustrated is a third type of contraction that can also be used in biceps curl (e.g., by body builders): an isokinetic contraction in which the movement is performed at a constant angular velocity thereby permitting maximal contraction throughout whole range of the motion. &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<\/p>\n<p>See <a href=\"agonist_muscle\">Agonist muscle<\/a>, <a href=\"antagonist_muscle\">Antagonist muscle<\/a>, <a href=\"force\">Force<\/a>, <a href=\"isometric_contraction\">Isometric contraction<\/a>, <a href=\"muscle_fiber\">Muscle fiber<\/a>, <a href=\"myosin\">Myosin<\/a>, <a href=\"striated_-or_striped_or_voluntary-_muscle\">Striated (or striped or voluntary) muscle<\/a>, <a href=\"velocity\">Velocity<\/a><\/p>\n<p><\/p>\n<p><\/p>\n<p><\/body><\/html><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Generation of muscle shortening without an increase in tension. &nbsp;Thus, muscle length changes, but tension remains unchanged, with the resultant movement of a body part. &nbsp;Such a voluntary contraction of skeletal muscle, can only happen when the maximal force of contraction generated by a muscle is greater than the external force acting on the muscle. &hellip; <\/p>\n<p class=\"link-more\"><a href=\"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/isotonic_contraction\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Isotonic contraction&#8221;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[2],"class_list":["post-8284","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-glossary","entry"],"_links":{"self":[{"href":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/wp-json\/wp\/v2\/posts\/8284","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/wp-json\/wp\/v2\/comments?post=8284"}],"version-history":[{"count":0,"href":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/wp-json\/wp\/v2\/posts\/8284\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/wp-json\/wp\/v2\/media?parent=8284"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/wp-json\/wp\/v2\/categories?post=8284"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/wp-json\/wp\/v2\/tags?post=8284"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}