University of Tehran Press Sport Biosciences 2008-9325 16 4 2025 02 19 Effects of Six Weeks of Specialized Training and C4 Supplementation During the Fitness Maintenance Phase on Physiological and Performance Variables in Male Futsal Players of the Iraqi Premier League Effects of Six Weeks of Specialized Training and C4 Supplementation During the Fitness Maintenance Phase on Physiological and Performance Variables in Male Futsal Players of the Iraqi Premier League 91 106 101186 10.22059/jsb.2025.382977.1654 FA Zaid Albahadoli Department of Sport Science, Faculty of Humanities, Tarbiat Modares University Shahnaz Shahrbanian Department of Sport Sciences, Faculty of Humanities, Tarbiat Modares University, Tehran Reza Gharakhanlou Department of Sport Science, Faculty of Humanities, Tarbiat Modares University, Tehran Ahmad Altamimi Faculty of Physical Education and Sports Sciences, University of Baghdad, Baghdad, Iraq Journal Article 2024 09 30 Introduction:<br />The short duration of the fitness maintenance phase in Iraqi futsal results in players being inadequately prepared for competitions. This study aimed to investigate the effects of a specialized training program and C4 supplementation during the fitness maintenance phase on VO₂max, lactate levels, speed endurance, agility, and speed in male Iraqi futsal players.<br />Methods:<br />This semi-experimental study utilized a pre-test and two post-test design, conducted after three and six weeks. A total of 45 futsal players were randomly assigned to three groups. The first experimental group (EX1) followed a specialized training program with C4 supplementation for six weeks, while the second experimental group (EX2) completed the same training program but received a placebo instead of C4. The control group (CON) continued their regular club training routine. <br />Results:<br />The results of the Mixed Model ANOVA indicated significant improvements in all variables (VO₂max, lactate, speed endurance, speed, and agility) after three and six weeks in the EX1 and EX2 groups (P < 0.05). However, no statistically significant changes were observed in the control group (P > 0.05). Additionally, there were no significant differences between the EX1 and EX2 groups for any of the measured variables.<br />Conclusion:<br />The specialized training program designed in this study demonstrated a significant positive impact on the selected physical fitness parameters, suggesting its potential as a pre-season training regimen for futsal players. However, C4 supplementation did not produce a statistically significant effect on any of the studied variables during this training phase. Introduction:<br />The short duration of the fitness maintenance phase in Iraqi futsal results in players being inadequately prepared for competitions. This study aimed to investigate the effects of a specialized training program and C4 supplementation during the fitness maintenance phase on VO₂max, lactate levels, speed endurance, agility, and speed in male Iraqi futsal players.<br />Methods:<br />This semi-experimental study utilized a pre-test and two post-test design, conducted after three and six weeks. A total of 45 futsal players were randomly assigned to three groups. The first experimental group (EX1) followed a specialized training program with C4 supplementation for six weeks, while the second experimental group (EX2) completed the same training program but received a placebo instead of C4. The control group (CON) continued their regular club training routine. <br />Results:<br />The results of the Mixed Model ANOVA indicated significant improvements in all variables (VO₂max, lactate, speed endurance, speed, and agility) after three and six weeks in the EX1 and EX2 groups (P < 0.05). However, no statistically significant changes were observed in the control group (P > 0.05). Additionally, there were no significant differences between the EX1 and EX2 groups for any of the measured variables.<br />Conclusion:<br />The specialized training program designed in this study demonstrated a significant positive impact on the selected physical fitness parameters, suggesting its potential as a pre-season training regimen for futsal players. However, C4 supplementation did not produce a statistically significant effect on any of the studied variables during this training phase. https://jsb.ut.ac.ir/article_101186_bb7eefd0a7000b80382b5900959899b6.pdf