{"626328":{"#nid":"626328","#data":{"type":"news","title":"A New Term in Biophysics: force\/time = \u201cyank\u201d","body":[{"value":"\u003Cp\u003EBiologists and biomedical engineers are proposing to define the term \u0026ldquo;yank\u0026rdquo; for changes in force over time, something that muscles cause and nerves can feel and respond to.\u003C\/p\u003E\r\n\r\n\u003Cp\u003ETheir ideas were published on September 12 in \u003Ca href=\u0022https:\/\/jeb.biologists.org\/content\/222\/18\/jeb180414\u0022\u003E\u003Cem\u003EJournal of Experimental Biology\u003C\/em\u003E\u003C\/a\u003E.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EExpressed mathematically, acceleration is the derivative of speed or velocity with respect to time. The term for the time derivative of acceleration is \u0026ldquo;jerk,\u0026rdquo; and additional time derivatives after jerk are called \u0026ldquo;snap,\u0026rdquo; \u0026ldquo;crackle\u0026rdquo; and \u0026ldquo;pop.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe corresponding term for force \u0026ndash; in physics, force is measured in units of mass times acceleration \u0026ndash; has never been defined, the researchers say.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EScientists that study sports often use the term \u0026ldquo;rate of force development\u0026rdquo;, a measure of explosive strength. Scientists who study gait and balance -- in animals and humans -- also often analyze how quickly forces on the body change. It could be useful in understanding spasticity, the abnormal activation of muscles from reflexes seen in multiple sclerosis, spinal cord injury, stroke and cerebral palsy.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;Understanding how reflexes and sensory signals from the muscles are affected by neurological disorders is how we ended up needing to define the rate change in force,\u0026rdquo; says Lena Ting, a researcher in the Petit Institute for Bioengineering and Bioscience and professor of rehabilitation medicine in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EHer co-authors are David Lin (Washington State University), Craig McGowan (University of Idaho), and Kyle Blum, a postdoctoral fellow at Northwestern who previously worked with Ting.\u003C\/p\u003E\r\n\r\n\u003Cp\u003ETing says Lin originally introduced her and Blum to the term \u0026ldquo;yank\u0026rdquo;.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;Dr. Ting and I were thinking similarly \u0026ndash; but separately \u0026ndash; that current terminology describing the time derivative of force was too unwieldy and limiting,\u0026rdquo; Lin says. \u0026ldquo;During an American Society of Biomechanics meeting, I suggested that \u0026lsquo;yank\u0026rsquo; was a possible term that we could use.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EOn a large scale, yank is relevant to the study of jumping, sprinting, capturing prey and maintaining balance, the researchers say. It is similarly useful in analyzing the behavior of muscles and tendons, sensory feedback and spinal reflexes, all the way down to the contributions of individual cells.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EA\u003Ca href=\u0022https:\/\/jeb.biologists.org\/content\/222\/15\/jeb196287.long\u0022\u003E companion paper from Blum and Ting\u003C\/a\u003E shows that in the leg muscles of a rat, yank in muscle fibers corresponds to the firing rates of muscle spindles, which are stretch receptors that detect changes in length of the muscle. Muscle spindles send signals to the nervous system so that the animal is aware of the body\u0026rsquo;s position in space. (see graph)\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe authors\u0026rsquo; research is supported by the Army Research Office (ARO 66554-EG), the National Science Foundation (NSF 1553550) and the National Institutes of Health (R01HD90642, R01HD46922, F31NS093855).\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Researchers enhance the vocabulary in the study of study of jumping, sprinting, capturing prey and maintaining balance"}],"field_summary":[{"value":"\u003Cp\u003EResearchers enhance the vocabulary in the study of study of jumping, sprinting, capturing prey and maintaining balance\u003C\/p\u003E\r\n","format":"limited_html"}],"field_summary_sentence":[{"value":"Research enhance the vocabulary in the study of study of jumping, sprinting, capturing prey and maintaining balance"}],"uid":"28153","created_gmt":"2019-09-17 23:15:14","changed_gmt":"2019-09-17 23:16:43","author":"Jerry Grillo","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2019-09-17T00:00:00-04:00","iso_date":"2019-09-17T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"626327":{"id":"626327","type":"image","title":"Yank","body":null,"created":"1568761553","gmt_created":"2019-09-17 23:05:53","changed":"1568761553","gmt_changed":"2019-09-17 23:05:53","alt":"","file":{"fid":"238451","name":"940pxwide-Lena-Yank-diagram.jpg","image_path":"\/sites\/default\/files\/images\/940pxwide-Lena-Yank-diagram.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/940pxwide-Lena-Yank-diagram.jpg","mime":"image\/jpeg","size":314218,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/940pxwide-Lena-Yank-diagram.jpg?itok=w9p0UcDL"}}},"media_ids":["626327"],"groups":[{"id":"1254","name":"Wallace H. Coulter Dept. of Biomedical Engineering"}],"categories":[],"keywords":[{"id":"126571","name":"go-PetitInstitute"},{"id":"1612","name":"BME"},{"id":"182376","name":"yank"},{"id":"182377","name":"spasticity"},{"id":"171587","name":"cerebral palsy"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}