en بيومکانيک ورزشی و شاخه‌های وابسته بدان Sport Biomechanics and its related branches مقاله اصیل Original Article <div style="text-align: justify;"><strong>Background. </strong>This study aimed to analyze core muscle fatigue effects on the kinematic parameters change during volleyball jump serve.<br> <strong>Methods. </strong>The participants were sixteen experienced male volleyball players with average age, height, and body weight of 24.6 &plusmn; 1.8 years, 1.85 &plusmn; 1.6 m, and 79.5 &plusmn; 3.5 kg, respectively. This study utilized two high-resolution video cameras, a drone video, a lactate analyzer, and a radar speed gun. Meanwhile, the eight kinematics parameters analyzed at the approach, plant, and jump phases showed that the ball speed decreased significantly in the fatigue condition compared to the non-fatigue counterpart.<br> <strong>Results. </strong>There was a significant difference in the jump phase duration, step length, and jump height variables for the fatigue and non-fatigue conditions during the jump serve in volleyball. Furthermore, the six kinematics parameters analyzed in the maximal shoulder external rotation phase showed a significant difference in fatigue and non-fatigue conditions found in the shoulder external rotation and trunk tilt backward parameters. Meanwhile, the maximum angular velocity phase at the upper limb joint during the jump serve showed that the variable shoulder internal rotation decreases significantly in the fatigue condition compared to the non-fatigue counterparts. Also, in the trunk rotation and trunk tilt forward, a significant decrease in the upper limb joint&rsquo;s maximum angular velocity was observed in the fatigue condition during the volleyball jump serve.<br> <strong>Conclusion. </strong>Fatigue reduces players&rsquo; performances during jump serve in volleyball, leading to slower ball speed and changes in body segment movements.</div> Volleyball, Sport Biomechanics, Core Muscle, Fatigue, Jump Serve 0 0 http://aassjournal.com/browse.php?a_code=A-11-1202-2&slc_lang=en&sid=1 Bu jang ilmu.keolahragaam1999@gmail.com 100319475328460011308 100319475328460011308 Yes Physical Education, Health and Recreation Study Program, Islam 45 Bekasi University, Jalan Cut Meutia No 83. Kota Bekasi, Jawa Barat 17114, Indonesia Agus Rusdiana Agus.Rusdiana@upi.edu 100319475328460011309 100319475328460011309 No Sport Science Study Program, Faculty of Sport and Health Education, Indonesia University of Education, Jalan Dr. Setiabudhi No.229 Isola Sukasari Bandung Jawa Barat, 40154, Indonesia. Sam sudin tripatriaandalanmedika891@gmail.com 100319475328460011310 100319475328460011310 No Physical Education Study Program, State University of Jakarta, Jalan Pemuda No.10, Rawamangun Kec Pulo Gadung Kota Jakarta Timur 13220 DKI Jakarta, Indonesia