Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 11 1 2025 6 1 Evaluation of Single-leg Balance during Landing from 20- and 40-centimeter Heights in Individuals with and without Chronic Ankle Instability 2 19 FA Usef Mohammadi Yaghoubi Department of Sport Biomechanics, Faculty of Sport Sciences, Bu-Ali Sina University, Hamedan, Iran. Nader Farahpour Department of Sport Biomechanics, Faculty of Sport Sciences, Bu-Ali Sina University, Hamedan, Iran. Muharram Mansoorizadeh Department of Computer Engineering, Bu-Ali Sina University, Hamedan, Iran. Gabriel Moisan Department of Human Kinetics, Université du Québec à Trois-Rivières, Québec, Canada. Objective This study aimed to assess balance performance using kinematic measures of the center of pressure during single-leg landings from two different heights in individuals with chronic ankle instability (CAI), and to compare the findings with those from healthy individuals. Methods A total of 34 male participants aged 20 to 40 years (17 with CAI and 17 healthy controls) were recruited. Participants performed single-leg landings from heights of 20 and 40 centimeters onto a Kistler force plate, followed by maintaining a single-leg standing posture for 10 seconds. The measured variables included path length, sway amplitude, mean radial displacement, and sway area of the center of pressure (COP). Multivariate analysis of variance (MANOVA) was used for between-group comparisons, and repeated-measures ANOVA was applied for within-group analyses. Results Individuals with CAI demonstrated significantly greater COP path length in the frontal plane during landings from both heights compared to the healthy group. Additionally, increasing the landing height was associated with significantly greater path length and sway amplitude in the sagittal plane, mean radial displacement, and COP sway area (p < 0.05). Conclusion The findings suggest that individuals with chronic ankle instability exhibit impaired balance, particularly in the frontal plane, during single-leg landings. Therefore, rehabilitation programs should focus on improving balance and stabilizing COP fluctuations by targeting the muscles involved in postural control. These results may inform therapeutic strategies and contribute to re-injury prevention in this population.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 11 1 2025 6 1 Comparison of the Ground Reaction Force Frequency Spectrum during Walking with and without Anti-Pronation Insoles in Individuals with Pronated Feet 20 33 FA Ebrahim Piri Department of Sports Biomechanics, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran. AmirAli Jafarnezhadgero Department of Sports Biomechanics, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran. Anders Stålman Department of Molecular Medicine and Surgery, Karolinska Institutet, Solna, Sweden. Saeid Alihosseini Department of Sports Physiology, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran. Yaghoub Panahighaffarkandi Department of Sports Physiology, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran. Objective Foot pronation is a common lower limb deformity that can affect human movement mechanics. Therefore, the aim of this study was to compare the frequency spectrum of ground reaction forces (GRFs) during walking with and without the use of an anti-pronation insole in individuals with pronated feet. Methods Twenty men with pronated feet (mean age: 21.12 ± 1.47 years; mean weight: 71.52 ± 5.18 kg; mean height: 178.15 ± 4.18 cm) voluntarily participated in this study. A foot scan system was used to measure the frequency spectrum of GRFs during walking, both with and without the anti-pronation insole. A paired t-test was conducted for statistical analysis. Results The results showed that the frequency at 99.5% power in the vertical component of the GRFs was significantly higher when using the insole compared to without it (p = 0.047, d = 0.85). Additionally, the frequency at 99.5% power was significantly higher with the insole in the big toe (p = 0.001, d = 0.30) and in toes 2 to 5 (p = 0.001, d = 0.29). Moreover, the frequency at 99.5% power in the vertical component of the first to fourth metatarsal regions was also significantly higher (p < 0.05). Conclusion The use of orthopedic insoles in individuals with pronated feet alters the biomechanical characteristics of gait and appears to enhance the distribution of vertical forces and the engagement of various foot structures.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 11 1 2025 6 1 The Effect of Six Weeks of TRX Training on Selected Physical Fitness Components in High School Students in Mashhad 34 45 FA Seyed Mojtaba Tabatabai Asl Department of Sports Pathology and Corrective Exercises, Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, Iran. Parvin Jalilian Department of Environmental Health Engineering, School of Health and Food Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran. Objective Physical fitness is an essential component of daily activities and is widely recognized as a key indicator for evaluating students' functional performance. This study aimed to examine the effect of six weeks of TRX suspension training on selected physical fitness components in high school students. Methods This semi-experimental, applied study was conducted in a field setting. The statistical sample consisted of 40 tenth-grade male students from a secondary school in Mashhad. Participants were randomly assigned to either a training group or a control group, with 20 students in each. The stork balance test was used to assess static balance; the modified pull-up test evaluated upper body muscular endurance; and the standing long jump and sit-and-reach tests measured lower limb power and hamstring flexibility, respectively. The training group followed a TRX suspension training program for six weeks, three sessions per week, with each session lasting 60 minutes. Results The results revealed significant improvements in balance, muscular endurance, and flexibility in the training group compared to the control group. However, no significant difference was observed between the groups in terms of lower limb power. Conclusion Overall, TRX suspension training appears to enhance endurance, balance, flexibility, and neuromuscular control of the core stabilizing muscles. Based on these findings, it is recommended that school physical education instructors incorporate TRX-based suspension training into their programs to improve various aspects of students’ physical and anthropometric fitness.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 11 1 2025 6 1 A Review of Training Protocols for Preventing Anterior Cruciate Ligament Injuries in Soccer Players 46 62 FA Moosareza Ghorbani Department of Sport Injuries and Corrective Exercise, Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, Iran. Mostafa Varmaziar Department of Sports injuries and Corrective exercise, Faculty of Physical Education and Sports Sciences, University of Tehran, Iran. Mona Heydarian Department of Biomechanics and Sports Injuries, Faculty of Physical Education and Sports Sciences, Kharazmi University, Karaj, Iran. Objective Anterior cruciate ligament (ACL) injuries are among the most common injuries in athletes, particularly soccer players. While numerous studies have examined the effectiveness of injury prevention programs for ACL injuries across various sports, no study was found that specifically reviewed training protocols for ACL injury prevention in soccer players. Therefore, the aim of this study was to review training protocols designed to prevent ACL injuries in soccer players. Methods This systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Articles published between 2000 and 2025 focusing on ACL injury prevention were searched. Relevant articles were identified using both English and Persian keywords, including: prevent ACL injury, knee injury prevention, prevention of knee injuries, injury prevention in soccer, knee prevention, neuromuscular training, injury prevention programs, neuromuscular intervention, prevention of ACL injuries, prevention of knee injuries in soccer, lower limb injury prevention, and soccer injury prevention programs. The search was carried out in both Persian and international databases, including Magiran, Medlib, ISC, SID, PubMed, Google Scholar, PEDro, Scopus, ScienceDirect, and Irandoc. Results After applying inclusion and exclusion criteria, a total of 20 articles were selected. Among these, 10 studies focused on general warm-up routines, while the remaining 10 investigated neuromuscular training programs. Conclusion ACL injury prevention programs incorporating both general warm-up routines and neuromuscular training appear effective in reducing the incidence of ACL injuries among soccer players. However, no single comprehensive program has yet been shown to be effective across all age groups and populations. A notable strength of these interventions is that none have been associated with an increased risk of injury. Nevertheless, due to the complexity and challenges involved in combining various exercise types, it remains difficult to definitively determine the superiority of one approach over another.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 11 1 2025 6 1 Biceps and Triceps Muscle Activation Under Progressive Loads: A Study on Functional Symmetry of the Upper Limbs 64 78 EN Haider Hashim Collage of Physical Education and Sports Sciences, Diyala University, Iraq. Saif Ali Mohammed Collage of Physical Education and Sports Sciences, Samarra University, Iraq. Bashar Mohammed Ali Collage of Physical Education and Sports Sciences, Diyala University, Iraq. Safaa A. Ismaeel Collage of Physical Education and Sports Sciences, Diyala University, Iraq. Mohammed Nasir Collage of Physical Education and Sports Sciences, Diyala University, Iraq. Objective This study aimed to assess the biomechanical aspects of neuromuscular balance in the upper limbs during closed-chain resistance training with progressively increasing loads. Specifically, it investigated how incremental load variations affect the recruitment of agonist and antagonist muscles and examined the biomechanical relationship between load intensity and muscle coordination. Methods A total of 22 healthy male participants (aged 23–26 years) with resistance training experience were included. The participants performed upper-limb exercises using a multi-gym resistance machine under a closed-chain kinetic setup. The protocol included three sets at 50%, 75%, and 90% of one-repetition maximum (1RM), each set comprising six repetitions with a 60-second rest interval. Electromyographic (EMG) data were collected using a MyoTrace 400 system, with surface electrodes placed on agonist and antagonist muscles following Noraxon placement standards. EMG signals were processed to compute root mean square (RMS) values, normalized to each participant’s maximum voluntary isometric contraction (MVIC). Statistical comparisons were performed using paired t-tests and one-way ANOVA (with Bonferroni post-hoc tests), with significance set at p < 0.05. Results EMG activity in both the biceps (agonist) and triceps (antagonist) muscles showed significant increases as the load progressed from 50% to 90% 1RM. At the highest load (90% 1RM), no statistically significant difference was observed between the right and left limb EMG amplitudes, indicating a high degree of bilateral neuromuscular symmetry. These results align with previous biomechanical studies demonstrating that progressive loading enhances motor unit recruitment and influences agonist–antagonist muscle activation patterns. Conclusion Closed-chain resistance training with incremental loading provides biomechanical evidence of enhanced upper limb muscle recruitment, contributing to improved movement stability, motor control, and neuromuscular balance. These findings highlight the importance of progressive resistance training in both athletic and rehabilitative settings for optimizing performance and reducing injury risk. Future research should further explore the effects of varying rest intervals and repetition schemes on neuromuscular adaptation to refine training guidelines.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 11 1 2025 6 1 The Effect of Six Weeks of High-Intensity Interval Training with and without Coenzyme Q10 Supplementation on Bench Press and Squat Strength in Competitive Male Bodybuilders 80 92 FA Javad Almasi Department of Physical Education and Sport Sciences, Ha. C. Islamic Azad University, Hamadan, Iran. Mohammad Mahdi Shabazbigian Department of Physical Education and Sport Sciences, Ha. C. Islamic Azad University, Hamadan, Iran. Objective Resistance training can be performed using external weights or body weight. It induces muscle tension, ultimately leading to increases in contractile proteins, muscle cross-sectional area, anaerobic power, speed, strength, muscular endurance, and motor function—all of which play key roles in enhancing athletic performance. This study aimed to investigate the effect of six weeks of high-intensity interval training (HIIT), with and without coenzyme Q10 supplementation, on the muscular strength of male bodybuilders in Hamadan. Methods This semi-experimental study involved a statistical population of 200 male bodybuilders in Hamadan. Thirty participants (mean age: 23.3 ± 0.4 years; height: 172 ± 6 cm; weight: 76 ± 2.6 kg), with no history of Q10 supplementation or HIIT during the previous six months, were randomly and voluntarily selected and assigned to two groups of 15. Ethical considerations were addressed using a health screening questionnaire and informed consent form. The experimental group underwent six weeks of HIIT combined with coenzyme Q10 supplementation, while the control group performed the same HIIT protocol with a placebo supplement of identical appearance and dosage. Muscular strength was assessed using Impulse fitness machines (manufactured in China), and one-repetition maximum (1RM) was calculated. Data were analyzed using the Shapiro–Wilk test and univariate and multivariate analysis of covariance (ANCOVA) via SPSS version 25. Results The results indicated significant improvements in muscular strength in both groups, with greater gains observed in the group receiving CoQ10 supplementation. In the bench press, 55% of the variance in post-test strength was attributed to the intervention (F = 33.58, p < 0.001, η² = 0.554), and in the squat, this effect reached 80% (F = 107.22, p < 0.001, η² = 0.799). Conclusion Six weeks of high-intensity interval training significantly improved upper and lower body strength in male bodybuilders. The combination of HIIT and CoQ10 supplementation was more effective than HIIT alone. These findings suggest that CoQ10 may serve as a beneficial supplement for enhancing muscular performance and mitigating fatigue in strength-based training programs.