Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 1 2026 6 1 Effects of Fatigue on Lower-Limb Coordination and Its Variability During Running in Semi-Professional Soccer Players 2 18 FA Mahtab Farrokhi Parashkoh Department of Sports Biomechanics, Faculty of Physical Education and Sport Sciences, Shahid Bahonar University of Kerman, Kerman, Iran. Mohammadreza Amirseyfaddini Department of Sports Biomechanics, Faculty of Physical Education and Sport Sciences, Shahid Bahonar University of Kerman, Kerman, Iran. Sasan Naderi Department of Sports Biomechanics, Faculty of Physical Education and Sport Sciences, Shahid Bahonar University of Kerman, Kerman, Iran. Objective The incidence of sports injuries has risen significantly. Fatigue, recognized as an influential risk factor, has recently garnered considerable attention. Given the importance of sports-related injuries and athletes’ well-being, this study aimed to investigate the effect of fatigue on lower-limb coordination and coordination variability during running in semi-professional soccer players. Methods Sixteen semi-professional male soccer players from Kerman City were randomly recruited. Participants completed treadmill running trials at a constant speed of 10.8 km/h, both before and after a fatigue protocol. Three-dimensional kinematic data were recorded using a six-camera motion analysis system operating at a sampling frequency of 230 Hz. The Koblauch–Baur protocol was used to induce fatigue. Continuous relative phase (CRP) analysis was performed using MATLAB R2022a to quantify coordination and coordination variability. CRP values were calculated for six couplings: hip–knee, knee–ankle, hip–ankle, left hip–right hip, left knee–right knee, and left ankle–right ankle. Paired-samples t-tests were conducted to compare pre- and post-fatigue measures. Results The paired t-tests revealed no significant differences in coordination or coordination variability between pre- and post-fatigue conditions across most couplings (p > 0.05). However, significant changes in coordination were observed for the hip–ankle, left knee–right knee, and left ankle–right ankle couplings following fatigue. Additionally, coordination variability differed significantly for the hip–knee coupling after fatigue (p < 0.05). Conclusion Fatigue affected the continuous relative phase of some lower-limb couplings, reducing coordination variability in certain cases. Although other couplings exhibited post-fatigue changes, these were not statistically significant. These findings suggest that fatigue exerts only a limited influence on lower-limb coordination and its variability in semi-professional soccer players.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 1 2026 6 1 Validation of a Low-Cost Inertial Sensor for Estimating Barbell Velocity During Deadlift Concentric Phase 20 34 FA Mostafa Haj Lotfalian Department of Physical Education and Sports Science, Faculty of Psychology and Educational Sciences, Yazd University, Yazd, Iran. Objective In velocity-based resistance training, accurate measurement of barbell velocity is crucial for load prescription, fatigue monitoring, and autoregulation. Given the limitations of reference systems such as motion capture, inertial measurement units (IMUs) have attracted increasing attention as low-cost, portable alternatives. This study aimed to validate a low-cost IMU for measuring barbell velocity during the concentric phase of the deadlift, using a motion capture system as the reference standard. Methods Sixteen young men (mean age = 21.7 ± 3.4 years) with at least one year of resistance training experience participated. After a standardized warm-up, each participant performed three sets of five deadlifts at 50% of their body mass. Barbell velocity was recorded simultaneously using a triaxial IMU and a 3D motion capture system. Data were analyzed under both filtered and unfiltered conditions. Vertical velocity was derived through sensor fusion and zero-velocity update algorithms. The third and fourth repetitions of each set were included in the analysis. Differences between measurement tools were examined using repeated-measures ANOVA, along with agreement and reliability indices. Results For mean velocity, no significant differences were found between the IMU and motion capture across processing conditions. The mean bias between devices was small (≈0.02 m/s), with high reliability and agreement indices (ICC ≈ 0.86; RMSE ≈ 0.16 m/s; CV ≈ 14%). In contrast, for peak velocity, significant main effects of measurement tool, filtering, and their interaction were observed. The IMU systematically underestimated peak velocity compared with motion capture, showing larger mean biases (up to −0.19 m/s), moderate correlations, and higher error indices. Conclusion The IMU demonstrated high agreement and low error for mean velocity, but greater variability for peak velocity. Thus, this low-cost, portable sensor can serve as a practical tool for monitoring mean concentric velocity during deadlifts in field settings, although caution is warranted when interpreting peak velocity values.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 1 2026 6 1 The Effect of Swedish Massage on Ergonomic Risk Factors and Occupational Range of Motion in Hairdressers with Musculoskeletal Disorders 36 50 FA Safoura Ghasemi Department of Biomedical Engineering, Faculty of Biomedical and Mechanical Engineering, Hamedan University of Technology, Hamedan, Iran. Shahnaz Shahrjerdi Department of Sports Physiology and Pathology, Faculty of Sports Sciences, Arak University, Arak, Iran. Fatemeh Kkalantari Department of Sports Physiology and Pathology, Faculty of Sports Sciences, Arak University, Arak, Iran. Objective Work-related musculoskeletal disorders (WMSDs) are among the leading causes of reduced productivity, diminished quality of life, and chronic disabilities in occupations involving repetitive movements and prolonged static postures. This study aimed to investigate the effect of a Swedish massage intervention on ergonomic risk factors and occupational range of motion in female hairdressers suffering from musculoskeletal disorders. Methods This semi-experimental applied study employed a pre-test/post-test design with experimental and control groups. The statistical population consisted of 42 female hairdressers with musculoskeletal disorders in Arak city. Pain-related data were collected using the Cornell Musculoskeletal Discomfort Questionnaire, while ergonomic risk factors were assessed via the Rapid Entire Body Assessment (REBA) tool. Occupational range of motion was measured using a goniometer. Participants were evaluated before and after a five-week Swedish massage intervention. Data normality was assessed using the Shapiro–Wilk test, variance homogeneity with Levene’s test, and between-group comparisons using independent t-tests or Mann–Whitney U tests. Within-group comparisons were conducted using paired t-tests or Wilcoxon tests. All analyses were performed in SPSS version 25 at a significance level of P ≤ 0.05. Results The results indicated a significant reduction in ergonomic risk scores in the experimental group (p ≤ 0.001) compared to the control group (p = 0.008). Occupational range of motion showed significant reduction across all six assessed regions in the experimental group (p ≤ 0.001) relative to the control group (p ≤ 0.011). Additionally, a significant between-group difference was observed in musculoskeletal disorder scores across all evaluated regions (p ≤ 0.033), with the experimental group showing a marked reduction compared to the control group. Conclusion A Swedish massage intervention significantly influences ergonomic risk factors and occupational range of motion in female hairdressers with musculoskeletal disorders.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 1 2026 6 1 Running Mechanics in Individuals with Anterior Cruciate Ligament Reconstruction 6–12 Months After Surgery: A Systematic Review and Meta-Analysis 52 69 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. Mahrokh Dehghani Department of Sports Biomechanics, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran. Farhad Rezazadeh Department of Sports Biomechanics, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran. Afsaneh Enteshari-Moghaddam Department of Internal Medicine, Faculty of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran. Objective This systematic review and meta-analysis aimed to examine the biomechanical characteristics of running in individuals who had undergone anterior cruciate ligament reconstruction (ACLR) at various postoperative time intervals. Methods A systematic search was performed in PubMed, Google Scholar, Scopus, SID, Magiran, ISC, ScienceDirect, JCR, and Web of Science from May 2010 to August 2025. Eligible studies included original research and clinical trials involving young adults (18–45 years) with a history of ACLR, no concomitant injuries, and full-text availability. After screening, 10 studies met the inclusion criteria. The methodological quality of the included articles was assessed using the Downs and Black checklist. Data on loading asymmetry, knee kinematics and kinetics, and muscle activation were synthesized using meta-analytic procedures. Results The results indicated significant biomechanical asymmetries in individuals with ACLR up to 18 months after surgery, including a 15–20% reduction in loading on the reconstructed limb, decreased knee extension moment (g = 0.80), greater knee flexion angle at initial contact, and reduced vertical ground reaction force. These deficits persisted even among athletes who had returned to sport, suggesting a sustained neuromuscular protective strategy. Conclusion Despite extended recovery periods, individuals with ACLR continue to exhibit persistent biomechanical deficits during running. These findings underscore the need for precise, biomechanically informed rehabilitation programs prior to return to sport.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 1 2026 6 1 Investigation of Chronic Ankle Instability in Athletes Using Artificial Neural Networks 70 88 FA Shahram Ahanjan Department of Sport Sciences and Health, Amirkabir University of Technology, Tehran, Iran. Komeil Dashti Rostami Department of Motor Behavior and Biomechanics, Faculty of Sport Sciences, University of Mazandaran, Babolsar, Iran. Ali Jalalvand Department of Sport Biomechanics, Ha.C., Islamic Azad University, Hamedan, Iran. Objective An artificial neural network (ANN) is an information-processing concept inspired by the biological nervous system, capable of handling data in a manner similar to the human brain. The key feature of this approach is its architecture, which consists of numerous interconnected processing elements that operate collectively to solve complex problems. Chronic ankle instability (CAI) is one of the most common and troublesome sequelae of acute ankle sprains. It is typically attributed to mechanical and functional instability, yet these categories do not fully capture the range of pathological conditions contributing to CAI. Therefore, the present study aimed to estimate and classify chronic ankle instability in athletes using artificial neural networks. Methods Forty athletes participated in this study and were divided into two groups: 20 athletes with chronic ankle instability and 20 without a history of ankle injury. The analyzed variables included height, weight, forefoot width, foot pronation, active and passive dorsiflexion, plantarflexion, inversion, and eversion ranges of motion (ROM), static postural control, and performance in the Illinois agility test. Independent t-tests and discriminant analyses were used for statistical comparisons. Subsequently, ANN modeling was applied to identify the most influential predictors of CAI. Results Data modeling with the optimal neural network achieved an R value of 0.9997, with a minimal error between the experimental and predicted data, indicating very high predictive accuracy. The ANN results identified forefoot width and passive inversion ROM as the most critical factors influencing ankle instability. Conclusion The artificial neural network demonstrated exceptional accuracy in predicting ankle instability. The findings suggest that increased forefoot width and excessive inversion range of motion are major contributors to chronic ankle instability. Preventive strategies such as the use of ankle braces or taping are recommended for athletes exhibiting these characteristics.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 1 2026 6 1 Differences in Speed and Aerobic Endurance among Players of Field and Court-Based Sports 90 107 EN Suvo Roy Department of Physical Education and Sports Science, Jashore University of Science and Technology, Jashore, Bangladesh. Md. Rayhan Rakib Office of the Physical Education, Jashore University of Science and Technology, Jashore, Bangladesh. Md. Arman Gazi Department of Physical Education and Sports Science, Jashore University of Science and Technology, Jashore, Bangladesh. Ummay Hafsa Rumky Department of Physical Education and Sports Science, Jashore University of Science and Technology, Jashore, Bangladesh. Mst. Khadiza Akter Department of Physical Education and Sports Science, Jashore University of Science and Technology, Jashore, Bangladesh. Alif Hasan Shefat Department of Management, Jashore University of Science and Technology, Jashore, Bangladesh. Nafis Alom Department of Finance and Banking, Jashore University of Science and Technology, Jashore, Bangladesh. Md. Azadul Islam School of Physical Education and Health Engineering, Taiyuan University of Technology, Taiyuan, Shanxi Province, China. Objective Speed and cardiovascular endurance are key components of athletic performance in both court-based and field-based sports. While these sports differ in playing environments and tactical demands, they share similar physical requirements. This study aims to evaluate and compare the speed and endurance levels of male court- and field-based athletes to inform training and performance strategies. Methods Sixty male Inter-University athletes (aged 18–25) from Jashore University of Science and Technology were randomly assigned to court-based (n = 30) and field-based (n = 30) groups. Speed was evaluated using the 4 × 10 m Shuttle Run and 50 m Sprint, while endurance was measured using the Beep Test and Cooper Test. Data were analyzed using SPSS (version 27), with independent samples t-tests conducted at a significance level of p< 0.05. Results Independent samples t-tests showed no statistically significant differences in either speed or endurance between athletes from field-based and court-based sports. Both the shuttle run and 50-meter sprint demonstrated comparable speed levels in the two groups. Similarly, endurance performance measured through the beep test and Cooper test showed no meaningful differences. Overall, athletes from field-based sports displayed slightly better average performance across all tests, although the differences were not statistically significant. Conclusion Court-based and field-based athletes demonstrated similar levels of key fitness components, with no significant differences observed in speed (shuttle run and 50-meter sprint) or endurance (beep test and Cooper test). Although field sport athletes showed slightly better performance, these differences were not statistically significant. These findings suggest that training programs targeting speed and endurance can be effectively implemented across both sport types.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 1 2026 6 1 A Narrative Review on Knee Pain in Relation to Distal Factors and Possibilities for Non-Pharmacological Management Including 3D Printing 108 134 EN Jay Prashant Darjee Department of Biomedical Engineering, North Eastern Hill University, Shillong, India. Monica Chhabra Department of Physiotherapy, Post Graduate Institute of Medical Education & Research, Chandigarh-160012, India. Prabhat Kumar Doctoral School of Basic Medicine, Medical School, University of Pécs, Pécs, Hungary. Daffylabeth Mawlieh Assam Down Town University, Guwahati, Assam, India. Nabeel Ahmad Department of Biotechnology, School of Allied Sciences, Dev Bhoomi Uttarakhand University—248007, Dehradun, India. Nitin Sahai Department of Biomedical Engineering, North Eastern Hill University, Shillong, India. Objective Knee pain is prevalent across all age groups, affecting approximately 25% of adults, with reported prevalence rates ranging from 10% to 60% depending on the underlying etiology. Over the past two decades, the incidence of knee pain has increased by nearly 65%, influenced by various causative factors—proximal, local, and distal. The effectiveness of its management largely depends on identifying and addressing the underlying cause. Methods A comprehensive literature search was conducted in PubMed, Google Scholar, Scopus, Web of Science, and ScienceDirect for articles published up to August 21, 2025. The keywords “Knee Pain,” “Foot Biomechanics,” “Non-Pharmacological Management,” “Physiotherapy,” “Physical Therapy,” and “3D Printing” were used individually and in combination. Results Non-pharmacological management of knee pain is shaped by its multifactorial etiology, encompassing biomechanical, anatomical, and functional factors. Among these, lower limb biomechanics and foot morphology–based interventions have demonstrated particular relevance. Conclusion This review emphasizes that knee pain is frequently influenced by distal factors such as foot biomechanics, limb alignment, and functional asymmetries. Addressing these factors through non-pharmacological interventions—including physiotherapy, orthotic modification, and emerging technologies such as 3D printing—offers promising directions for individualized care. Integrating biomechanical assessment with innovative rehabilitation strategies may enable clinicians to achieve more effective, patient-specific management of knee pain.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 1 2026 6 1 Effects of Vestibular Disturbances on Lower-Limb Muscle Activation in Active Children During the Stance Phase of Gait 136 153 FA Morteza Mansoori Department of Physical Education and Sport Sciences, Central Tehran Branch, Islamic Azad University, Tehran, Iran. Saeed Ilbeigi Department of Sports Sciences, University of Birjand, Birjand, Iran. ALi Fatahi Department of Physical Education and Sport Sciences, Central Tehran Branch, Islamic Azad University, Tehran, Iran. Objective The vestibular system is one of the primary components involved in maintaining balance, and its dysfunction can influence gait biomechanics. This study aimed to examine the effect of vestibular disturbances on the electrical activity of selected lower-limb muscles in active children during the stance phase of walking. Methods This study was conducted on 30 boys aged 7–11 years in Tehran, selected through convenience sampling. An 8-channel EMG system was used to record the electrical activity of selected lower-limb muscles across four sensory conditions: walking with eyes open, walking with eyes closed, walking with eyes open with vestibular disturbance, and walking with eyes closed with vestibular disturbance. Data were analyzed using repeated-measures ANOVA and MANOVA at a significance level of p ≤ 0.05. Results Significant changes were observed in the activity of the biceps femoris (p = 0.001), soleus (p = 0.001), and peroneus longus (p = 0.034) across different walking conditions. No significant differences were found in the right quadriceps (p = 0.304), the medial hamstring (p = 0.222), or the tibialis anterior (p = 0.054). Conclusion The findings suggest that imbalance induced by vestibular disturbances can alter the activation patterns of lower-limb muscles during walking, potentially leading to long-term gait deviations. These results highlight the importance of strengthening vestibular function in children to reduce potential mobility-related risks later in life.