en فیزیولوژی ورزشی Sport Physiology تحقيقي Original Paper <span style="font-size:11pt"><span style="line-height:200%"><span style="unicode-bidi:embed"><span calibri="" style="font-family:"><b><span style="font-size:12.0pt"><span style="line-height:200%"><span new="" roman="" style="font-family:" times="">Background and objectives</span></span></span></b><span style="font-size:12.0pt"><span style="line-height:200%"><span new="" roman="" style="font-family:" times="">: The role of genetic components in expression of proteins involved in signaling pathways of fat and carbohydrate metabolism has been well-demonstrated. The aim of this study was to determine effects of high intensity interval training (HIIT) on glucose, insulin, and insulin resistance levels as well as <i>IRS1</i> expression in gastrocnemius muscle of obese Wistar rats.</span></span></span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:200%"><span style="unicode-bidi:embed"><span calibri="" style="font-family:"><b><span style="font-size:12.0pt"><span style="line-height:200%"><span new="" roman="" style="font-family:" times="">Methods</span></span></span></b><span style="font-size:12.0pt"><span style="line-height:200%"><span new="" roman="" style="font-family:" times="">: The study included 14 male, Wistar rats (aged 10 weeks) weighting 220 &plusmn; 20 g. Obesity was induced in all rats via exposure to a high-fat diet for six weeks. Then, the rats were randomly divided into a HIIT group (n=7) and a control group (n=7). The rats in the HIIT group performed treadmill running, five sessions a week, for eight weeks. Levels of fasting glucose, serum insulin, insulin resistance, and <i>IRS1</i> expression in the gastrocnemius muscle of the rats were measured after the last training session. Data were analyzed by the independent t-test at statistical significance of 0.05.</span></span></span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:200%"><span style="unicode-bidi:embed"><span calibri="" style="font-family:"><b><span style="font-size:12.0pt"><span style="line-height:200%"><span new="" roman="" style="font-family:" times="">Results</span></span></span></b><span style="font-size:12.0pt"><span style="line-height:200%"><span new="" roman="" style="font-family:" times="">: The HIIT intervention significantly decreased fasting glucose compared with the control group (<i>p</i><0.0001). It also resulted in a significant decrease in serum insulin levels and insulin resistance compared with the control group (<i>p</i><0.0001). Moreover, the HIIT training significantly increased <st1:stockticker w:st="on"><i>IRS</i></st1:stockticker><i>1</i> expression (<i>p</i>=0.030) in the gastrocnemius muscle of rats. </span></span></span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:200%"><span style="unicode-bidi:embed"><span calibri="" style="font-family:"><b><span style="font-size:12.0pt"><span style="line-height:200%"><span new="" roman="" style="font-family:" times="">Conclusion</span></span></span></b><span style="font-size:12.0pt"><span style="line-height:200%"><span new="" roman="" style="font-family:" times="">: Based on the available evidence, the increase in insulin function and the decrease in insulin resistance can be attributed to increased <i>IRS1</i> expression in the gastrocnemius muscle following HIIT training.</span></span></span></span></span></span></span> High intensity interval training,Obesity,muscles, 30 35 http://mlj.goums.ac.ir/browse.php?a_code=A-10-953-1&slc_lang=en&sid=1 zahra zojaji zojaji.1374@gmail.com 100319475328460022142 100319475328460022142 No Department of Physical Education and Sport Sciences, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran saqqa farajtabar behrestaq farajtabarp@yahoo.com 100319475328460022143 100319475328460022143 Yes Department of Physical Education and Sport Sciences, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran babisan askari babisan.askari@gmail.com 100319475328460022144 100319475328460022144 No Department of Physical Education and Sport Sciences, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran