Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 Age-Related Anthropometric Changes in Schoolboys Aged 12 to 14 154 170 EN Md. Arman Gazi Department of Physical Education and Sports Science, Jashore University of Science and Technology, Jashore, Bangladesh. Suvo Roy Department of Physical Education and Sports Science, 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. Md. Abdullah Department of Physical Education and Sports Science, Jashore University of Science and Technology, Jashore, Bangladesh. Asit Mahara Department of Physical Education and Sport Science, Panskura Banamali College, Vidyasagar University, Panskura, West Bengal, India. Aminur Rahaman Department of Physical Education and Sports Sciences, University of Delhi, Delhi, India. Md. Rayhan Rakib Office of the Physical Education, Jashore University of Science and Technology, Jashore, Bangladesh. Objective Childhood obesity and under nutrition are emerging public health challenges in many developing countries, including Bangladesh. Accurate assessment of growth and body composition through anthropometric measures is essential for monitoring children's health and guiding effective intervention strategies. This study aims to assess growth status by examining body composition changes using anthropometric measurements in schoolboys aged 12 to 14 years from Jashore, Bangladesh. Methods The study involved 90 schoolboys aged 12 to 14 years from Jashore, Bangladesh, who were assessed using standardized anthropometric techniques. Skinfold measurement sat the suprailiac, subscapular, and triceps sites were taken using precision calipers for body fat estimation. Considering these measurements, fat mass and lean body mass was calculated. Results ANOVA results revealed significant age-group differences in triceps, subscapular, and suprailiac skinfold thicknesses, fat percentage, fat mass, and lean body mass (p < 0.01), indicating that body composition varies notably with age. Specifically, 13- and 14-year-olds showed significantly higher skinfold thickness, fat percentage, and fat mass compared to 12-year-olds (p < 0.001). Lean body mass was significantly greater in 14-year-olds compared to both 12- and 13-year-olds (p < 0.001). These findings indicate that fat percentage and lean body mass generally increase progressively with age, reflecting natural developmental changes during early adolescence. Conclusion This study demonstrates that body composition significantly changes with age among schoolboys aged 12 to 14 in Jashore, Bangladesh. Older boys exhibited higher skinfold thicknesses, fat percentage, and fat mass, alongside a marked increase in lean body mass, indicating a natural progression in physical development during early adolescence. These findings emphasize the value of regular anthropometric measurements for monitoring growth patterns and supporting age-appropriate dietary and medical interventions for school-age children.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 The Interactive Effect of Pre-Landing Skill Complexity and Fatigue on Biomechanical Landing Patterns in Female Taekwondo Athletes 172 191 FA Shahrzad Masoumi Department of Physical Education, Rasht Branch, Islamic Azad University, Rasht, Iran. Objective Landing is a movement phase commonly associated with lower-limb injuries. Although various factors influencing landing mechanics have been examined, the role of execution complexity has received comparatively little attention. This study examined how task complexity affects landing performance under fatigue by comparing a taekwondo jump kick, representing a complex movement, with a countermovement jump, representing a simple task. Methods Kinematic and kinetic data were collected using a motion analysis system and a portable force platform. The experimental protocol consisted of two repeated phases. First, six highly skilled female welterweight taekwondo athletes performed the landing tasks using both their dominant and non-dominant legs. Immediately afterward, they completed a standardized fatigue protocol. This sequence was repeated continuously without rest until exhaustion, and each athlete completed four full cycles. Results The findings indicated that hip joint angles were the most affected variables following the reduction in hip extensor and knee flexor strength induced by fatigue. The most pronounced differences between the simple and complex tasks appeared in the kinematic variables. Fatigue increased the disparity between the two tasks in the dominant leg, whereas in the non-dominant leg this difference decreased. Another notable observation was the shift in the direction of asymmetry in several variables when comparing the rested and fatigued conditions. In the simple task, changes in asymmetry direction occurred in five variables, while in the complex task such changes were observed in eight variables. Conclusion The combined influence of skill complexity, fatigue, and limb dominance leads to distinct landing patterns in female taekwondo athletes. These results emphasize the need for further investigation of this interaction across a broader range of sport-specific skills.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 Effects of Alexander Technique Exercises on Static and Dynamic Balance in Female Students with Attention Deficit/Hyperactivity Disorder 192 208 EN Neda sadat Mousavi Askari Department of Sport Injury and Corrective Exercises, Faculty of Sport Sciences, Shahid Rajaee Teacher Training University, Tehran, Iran. Mohammad Kalantariyan Department of Sport Injury and Corrective Exercises, Faculty of Sport Sciences, Shahid Rajaee Teacher Training University, Tehran, Iran. Mohammad Rahimi Department of Sport Injury and Corrective Exercises, Faculty of Sport Sciences, Shahid Rajaee Teacher Training University, Tehran, Iran Objective This study aimed to examine the effects of exercises based on the Alexander Technique on static and dynamic balance in female students aged 13 to 16 years diagnosed with Attention Deficit/Hyperactivity Disorder (ADHD). Methods A quasi-experimental pretest–posttest design with a control group was employed. After initial screening using the Conners’ Parent Rating Scale and diagnostic confirmation through IVA-CPT software and clinical interviews, 30 eligible students were selected through purposive sampling and randomly assigned to an experimental group (n = 15) or a control group (n = 15). The experimental group participated in Alexander Technique training sessions twice per week for eight weeks. Static and dynamic balance were assessed using the Stork Stand Test and the Y-Balance Test in the anterior, posteromedial, and posterolateral directions. Data were analyzed using ANCOVA with the significance level set at 0.05. Results ANCOVA results showed a statistically significant improvement in both static and dynamic balance in the experimental group compared with the control group at posttest (p < 0.01). Conclusion Alexander Technique exercises, through emphasizing body awareness, postural alignment, and neuromuscular control, can effectively improve balance performance in children with ADHD. These findings support the use of Alexander-based interventions as a low-cost and practical option in educational and rehabilitation settings aimed at enhancing motor function in this population.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 Effects of Sports Surface Stiffness on Time–Frequency Features of Vertical Ground Reaction Forces During Hopping 210 222 FA Abbas Farjad Pezeshk Faculty of Physical Education and Sport Sciences, Department of Sport Sciences, University of Birjand, Birjand, Iran. Heydar Sadeghi Faculty of Physical Education and Sport Sciences, Department of Sport Biomechanics, Kharazmi University, Tehran, Iran. Zahra Mousavi Faculty of Physical Education and Sport Sciences, Department of Sport Sciences, University of Birjand, Birjand, Iran. Objective The mechanical interaction between the human body and sports surfaces plays a critical role in maintaining functional stability and minimizing mechanical load. This study ergonomically examined sports surface stiffness within the typical indoor range (300–500 kN/m) and its influence on lower-limb mechanical behavior during a cyclic hopping task. Methods Thirty male athletes with similar training backgrounds performed hopping across four stiffness conditions. Vertical ground reaction force (vGRF) data were collected using a force plate and analyzed via Fast Fourier Transform (FFT). Peak force, median frequency, and the 99.5% frequency components of the vGRF were compared across surfaces using repeated-measures ANOVA with Bonferroni-adjusted post hoc tests (α = 0.05). Results Median frequency on the force plate was significantly higher than on all other surfaces (p < 0.001; large effect size η² = 0.437). The 99.5% frequency was greatest on the 500 kN/m surface (η² = 0.348), although the 300 kN/m surface did not differ from the force plate (p > 0.05). Conversely, peak vGRF was lowest on the 500 kN/m surface (p < 0.001; very large effect size η² = 0.654). Conclusion The 300 kN/m surface produced more favorable force-frequency characteristics, whereas the 500 kN/m surface reduced mechanical loading. Overall, a stiffness range between 300 and 500 kN/m may provide an optimal balance between minimizing potentially injurious loading in both time and frequency domains. These findings offer practical guidance for the ergonomic design of sports flooring and training environments.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 The Effect of Equine-Assisted Therapy and Play Therapy on Gross Perceptual-Motor Performance and Related Biomechanical Parameters in Adolescents with Autism 224 241 FA zahra Ghadimi kalateh Department of Motor Behavior, Faculty of Physical Education and Sports Sciences, University of Tehran, Tehran, Iran. Mahmoud Sheikh Department of Motor Behavior, Faculty Department of Motor Behavior, Faculty of Physical Education and Sports Sciences, University of Tehran, Tehran, Iran. Physical Education and Sports Sciences, University of Tehran, Tehran, Iran Seyyed Fardin Qeysari Department of Motor Behavior, Faculty of Physical Education and Sports Sciences, University of Tehran, Tehran, Iran. Davood Hoomanian Department of Motor Behavior, Faculty of Physical Education and Sports Sciences, University of Tehran, Tehran, Iran. Fazlollah Bagherzadeh Department of Motor Behavior, Faculty of Physical Education and Sports Sciences, University of Tehran, Tehran, Iran. Objective Autism Spectrum Disorder (ASD) is a neurodevelopmental condition marked by social communication difficulties and repetitive behaviors, often accompanied by motor skill impairments. This study aimed to examine the effects of equine-assisted therapy and play therapy on perceptual–motor performance and key biomechanical parameters in adolescents with ASD. Methods This semi-experimental study employed a pretest–posttest design with a control group. Thirty-six adolescents with ASD (25 boys, 11 girls), aged 10–14 years, were recruited through convenience sampling. Participants were matched based on age, gender, and disorder severity, then randomly assigned to one of three groups: equine-assisted therapy (n = 12), play therapy (n = 12), or control (n = 12). The interventions were delivered over eight weeks, consisting of five 30-minute sessions per week. The control group continued their routine center-based activities. Running speed and agility, balance, bilateral coordination, and strength were assessed one day before and one day after the intervention period using the Bruininks–Oseretsky Test. Data were analyzed using paired-sample t-tests, analysis of covariance (ANCOVA), and Bonferroni post hoc tests. Results Both equine-assisted therapy and play therapy produced significant improvements in overall perceptual-motor skills and all subtests (p < 0.005), whereas the control group showed no significant changes. ANCOVA revealed significant between-group differences, and Bonferroni post hoc analyses indicated that the control group scored lower than both intervention groups (p ≤ 0.005). Additionally, the equine-assisted therapy group outperformed the play therapy group in overall gross perceptual-motor scores and most subtests, although no significant difference was observed for bilateral coordination (p = 0.476). Conclusion The findings indicate that active, movement-based interventions—particularly equine-assisted therapy—can substantially enhance perceptual-motor skills and related biomechanical parameters in adolescents with ASD. The integration of motor, balance, and muscle-activation stimuli within these interventions appears to play a central role in improving motor performance and body coordination.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 Effects of Training Interventions on Walking and Running Mechanics in Individuals with Pronated Feet: A Systematic Review 242 263 FA Leila Sabouri Department of Sports Biomechanics, Faculty of Sports Sciences, Shahid Bahonar University of Kerman, Kerman, Iran. Fateme Rajani Department of Sports Biomechanics, Faculty of Sports Sciences, Shahid Bahonar University of Kerman, Kerman, Iran. Ebrahim Piri Department of Sports Biomechanics, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran. Objective Foot pronation is a common biomechanical condition characterized by excessive inward rotation of the foot during walking or running. This systematic review aimed to examine the effects of training and rehabilitation interventions on walking and running mechanics in individuals with pronated feet. Methods This study followed a systematic review design. Relevant articles published between January 2018 and March 2025 were identified through searches of Web of Science, Scopus, PubMed, Google Scholar, the Scientific Information Database (SID), Magiran, and the Islamic World Science Citation Database (ISC). Keywords included pronated foot, exercise training, orthotics, shoes, walking, and running. Original research studies and clinical trials that investigated biomechanical outcomes were included. Results Out of 82 initially identified studies, 21 met the inclusion criteria, comprising 10 studies on walking and 11 on running. Walking-related studies showed that targeted exercise programs and specific training environments increased muscle activity and improved foot and ankle mechanics in individuals with pronated feet, while orthotic interventions reduced excessive foot rotation and optimized plantar force distribution. Running-related studies indicated that orthoses and motion-control footwear improved biomechanical efficiency by enhancing muscle activation, reducing ankle dorsiflexion, lowering vertical loading rates, and improving load distribution. Overall, both exercise-based and supportive interventions improved walking and running mechanics and may reduce injury risk by limiting excessive pronation. Conclusion The findings indicate that targeted exercise programs, orthotics, footwear, and insoles can meaningfully improve biomechanical performance and reduce injury risk in individuals with pronated feet during walking and running. However, intervention type and training intensity should be individualized based on functional demands and activity type.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 Effects of a 6-Week TRX Training Program with and without Curcumin Supplementation on Ground Reaction Forces and Center of Pressure in Overweight Women with Nonspecific Chronic Low Back Pain 264 285 FA Ghodsiyeh Khazaei Department of Sports Science, Faculty of Sport Sciences, University of Birjand, Birjand, Iran. Saeed Ilbeigi Department of Sports Science, Faculty of Sport Sciences, University of Birjand, Birjand, Iran. Marziyeh Saghebjoo Department of Sports Science, Faculty of Sport Sciences, University of Birjand, Birjand, Iran. Abbas Farjad Pezeshk Department of Sports Science, Faculty of Sport Sciences, University of Birjand, Birjand, Iran. Objective Chronic nonspecific low back pain (NSCLBP) is commonly associated with altered gait mechanics and impaired postural control, particularly in overweight and obese individuals. Resistance-based training such as TRX and anti-inflammatory supplements like curcumin may offer therapeutic benefits. This study investigated the effects of a six-week TRX training program combined with curcumin supplementation on ground reaction forces and center of pressure measures during walking and static standing in overweight and obese women with NSCLBP. Methods This quasi-experimental, pretest–posttest study included 36 overweight and obese women with NSCLBP, who were randomly assigned to three groups: control (n = 12), TRX training plus curcumin supplementation (n = 12), and TRX training plus placebo (n = 12). GRF variables, dynamic COP measures during walking, and static COP parameters were assessed at baseline and after the six-week intervention. The TRX training protocol was performed three times per week by both training groups, with either curcumin or placebo supplementation administered throughout the intervention period. Between-group differences in outcome changes (Δ = posttest − pretest) were analyzed using one-way analysis of variance, with the significance level set at P ≤ 0.05. Results The results indicated that six weeks of TRX training, irrespective of supplementation, led to significant reductions in selected GRF variables during walking compared with the control group (P ≤ 0.05). In contrast, no significant between-group differences were observed for dynamic COP measures during walking or for static postural COP parameters following the intervention. Conclusion A six-week TRX training program, with or without curcumin supplementation, effectively reduced ground reaction forces during walking in overweight and obese women with NSCLBP. However, neither TRX training nor curcumin supplementation produced significant changes in dynamic or static COP measures. These findings suggest that TRX-based resistance training may primarily influence kinetic aspects of gait rather than postural control mechanisms in this populationldren.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 Changes in Lower Limb Strength and Neuromuscular Control during One Year of Military Training in Officer Cadets 286 300 FA Hamid Omidi Department of Physical Education and Sport Sciences, Faculty of Command and management, Imam Ali Military' University, Tehran, Iran. Reza Sabzevari Rad Department of Physical Education and Sport Sciences, Faculty of Command and management, Imam Ali Military' University, Tehran, Iran. moosareza Ghorbani Department of Sport Injuries and Corrective Exercise, Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, Iran. Objective This study aimed to examine the effects of one year of intensive military training on strength indices and neuromuscular variables, including dynamic balance and lower-limb proprioception, in officer cadets. In addition, the effectiveness of the military training program as a stand-alone intervention—without supplementary training modalities—was evaluated in eliciting favorable neuromuscular adaptations. Methods This longitudinal, prospective observational study was conducted on 30 officer cadets from Imam Ali University (mean age: 19.71 ± 2.03 years; mean height: 182.66 ± 6.21 cm; mean body mass: 71.83 ± 7.71 kg). Lower-limb muscle strength, dynamic balance, and knee joint proprioception were assessed at baseline and after one year of military training. Data were analyzed using repeated-measures analysis of variance (ANOVA) in SPSS version 26. Results After one year of military training, significant improvements were observed in dynamic balance in the anterior (p = 0.009, η² = 0.18) and posterolateral (p = 0.042, η² = 0.20) directions. Knee joint angular reproduction error at 45° in the dominant limb decreased significantly (p = 0.024). Muscle strength in the dominant limb increased significantly for hip flexion (p = 0.007), hip extension (p = 0.041), hip internal rotation (p = 0.009), knee extension (p = 0.016), and ankle dorsiflexion (p = 0.037). Moreover, significant differences between the dominant and non-dominant limbs were observed for posteromedial balance (p = 0.028), posterolateral balance (p = 0.006), and the composite balance score (p < 0.001). A significant interaction effect was also identified in the posterolateral balance direction (p = 0.048, η² = 0.20). Conclusion The findings demonstrate that one year of military training has a positive and significant effect on key neuromuscular performance indicators, including dynamic balance, proprioceptive accuracy, and lower-limb muscle strength in officer cadets. The observed improvements—particularly in the dominant limb—underscore the role of intensive and varied military training in promoting robust neuromuscular adaptations. These results may inform the design of optimized training programs for military and athletic populations.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 Kinematic Changes of Lower-Limb Joints During Walking in Individuals with Chronic Ankle Instability on Flat and Inclined Surfaces 302 319 FA Vahid Asghari 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. Shawn Robbins Department of Physiotherapy, McGill University, Montreal, QC, Canada. Gabriel Moisan Department of Human Kinetics, Université du Québec à Trois-Rivières, Trois-Rivières, Canada. Mahdi Majlesi Department of Sport Biomechanics, Ha.C. Islamic Azad University, Hamedan, Iran. Objective This study aimed to compare movement patterns, spatiotemporal variables, and joint range of motion of the lower limbs during walking between individuals with chronic ankle instability (CAI) and healthy controls on two surfaces: flat and inclined. Methods Eighteen individuals with chronic ankle instability (experimental group) and nineteen healthy participants (control group), aged 20 to 40 years, took part in this study. Lower-limb joint angles and spatial positions were recorded during walking on a flat surface and an externally inclined surface using a Qualisys motion capture system. Kinematic data were analyzed over a complete gait cycle. Between-group comparisons were performed using parametric one-dimensional statistical parametric mapping (independent SPM{t}) and multivariate analysis of variance (MANOVA). Results Stride length during walking on the flat surface was significantly shorter in the experimental group compared with the control group (p = 0.005). No significant between-group differences were observed in overall joint range of motion. However, compared with controls, the experimental group exhibited greater hip flexion (p = 0.038) and greater hip adduction (p = 0.003) during walking on the flat surface. On the inclined surface, the experimental group demonstrated greater hip flexion (p = 0.001), greater hip adduction (p = 0.001), greater knee flexion (p = 0.023), reduced knee external rotation (p = 0.001), greater ankle inversion (p = 0.001), higher plantarflexion velocity (p = 0.013), higher eversion velocity (p = 0.001), and greater ankle adduction velocity (p = 0.003). Conclusion Individuals with chronic ankle instability exhibit altered gait patterns and lower-limb joint kinematics during walking. These biomechanical alterations are not confined to the ankle joint but extend to more proximal joints, including the knee and hip. Rehabilitation programs for individuals with ankle instability should therefore incorporate targeted strengthening and neuromuscular training of the hip and knee musculature in addition to ankle-focused interventions.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 Effects of Vitamin D Supplementation on Achilles Tendon Biomechanics in Healthy Male Wistar Rats 320 336 FA Mohammad Soltani Department of Sports Biomechanics, CT.C, Islamic Azad University, Tehran, Iran. Ali Fatahi Department of Sports Biomechanics, CT.C, Islamic Azad University, Tehran, Iran. Fatemeh Heidari Cellular and Molecular Research Center, Qom University of Medical Sciences, Qom, Iran. Objective Vitamin D is considered a modifiable factor influencing tendon health and function through its effects on cellular activity and extracellular matrix organization. This experimental study aimed to investigate the effects of an eight-week vitamin D supplementation protocol on the biomechanical properties of the Achilles tendon in male Wistar rats. Methods Thirty male Wistar rats were randomly allocated to three groups (n = 10 per group): control, paraffin (vehicle), and vitamin D supplementation (500 IU/kg, three times per week). Biomechanical properties of the Achilles tendon—including maximum force (Fmax), stiffness, deformation, and absorbed energy—were assessed using uniaxial tensile testing 24 hours after the intervention period. Data were analyzed using one-way analysis of variance (ANOVA), with the significance level set at p < 0.05. Results No significant differences were observed among the groups for Fmax (p = 0.960), stiffness (p = 0.189), deformation (p = 0.137), or absorbed energy (p = 0.716). These results indicate that vitamin D supplementation at the applied dose and duration did not induce measurable biomechanical adaptations in the Achilles tendon of healthy male rats. Conclusion Eight weeks of vitamin D supplementation had no significant effect on the biomechanical properties of the Achilles tendon in healthy male Wistar rats, suggesting a limited role for vitamin D under normal physiological conditions. Tendon impairment appears to be more closely associated with vitamin D deficiency, whereas supplementation beyond adequate levels may confer minimal additional biomechanical benefit. Future studies should investigate different dosing regimens, longer intervention periods, deficiency models, and potential interactions with mechanical loading, exercise, or co-nutrients such as calcium and omega-3 fatty acids, as well as possible sex-specific responses. Overall, maintaining sufficient vitamin D status appears essential for preserving tendon integrity rather than enhancing tendon biomechanics beyond baseline levels.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 Effects of Aquatic Balance–Strength Training on Direction‑Specific Changes in Center of Pressure Velocity and Displacement Amplitude in Postmenopausal Women with Osteoporosis 338 356 FA Ava Mahdizadeh Department of Sports Biomechanics, CT.C., Islamic Azad University, Tehran, Iran. Heydar Sadeghi Department of Sport Biomechanics and Injuries, Faculty of Physical Education and Sports Sciences, Kharazmi University Tehran, Iran. Pedram Tehrani Department of Mechanical Engineering, CT.C., Islamic Azad University, Tehran, Iran. Objective This study aimed to determine the effect of a structured aquatic balance–strength training program on anteroposterior and mediolateral center of pressure (COP) velocity and displacement in postmenopausal women with osteoporosis. Methods In this randomized quasi-experimental study, 24 postmenopausal women with osteoporosis were randomly allocated to either an experimental or control group. The experimental group completed a 12-week aquatic balance–strength training program. Postural control was assessed using a Kistler force plate (Model 9260AA6) by calculating COP mean velocity and displacement amplitude in the anteroposterior and mediolateral directions during four standing tasks: (1) bipedal stance with eyes open, (2) bipedal stance with eyes closed, (3) semi-tandem stance with eyes open, and (4) semi-tandem stance with eyes closed. Data were analyzed using paired t-tests and analysis of covariance (ANCOVA) in SPSS (version 21), with the significance level set at 0.05. Results After adjustment for baseline values using ANCOVA, the experimental group demonstrated significant improvements in COP mean velocity and displacement amplitude in both directions compared with the control group (p < 0.05). Pre- to post-test change scores further confirmed that these improvements occurred exclusively in the training group, whereas no significant changes were observed in the control group. Improvements were particularly pronounced in the anteroposterior direction and under more challenging stance conditions, such as reduced base of support or eyes-closed tasks. Conclusion Aquatic balance–strength training significantly enhances postural control in postmenopausal women with osteoporosis by improving anteroposterior and mediolateral COP measures. Longitudinal studies with extended follow-up periods are needed to determine the persistence of these adaptations.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 12 2 2026 9 1 Comparison of Symmetrical and Asymmetrical Bag-Carrying on the Vertical Ground Reaction Force During Walking in Healthy Adults 358 371 FA Yasin Hosseini Department of Sport Science, Faculty of Literature and Humanities, Malayer University, Malayer, Iran. Objective Symmetrical and asymmetrical bag carrying during repetitive activities such as walking may increase mechanical loading and potentially elevate the risk of musculoskeletal injury. Analysis of ground reaction forces (GRF) during walking is therefore of clinical relevance. The aim of this study was to investigate the vertical ground reaction force during different symmetrical and asymmetrical bag-carrying conditions. Methods Seventeen female university students voluntarily participated in this study. Vertical ground reaction force data were recorded using an RSscan foot scanner at a sampling frequency of 300 Hz. Two asymmetrical carrying conditions (single-hand carrying and single-shoulder carrying) were compared with two symmetrical conditions (backpack and front pack). Results Carrying a bag with one hand resulted in a significantly higher loading rate compared with single-shoulder carrying (P = 0.007) and backpack carrying (P = 0.005). However, no significant difference in loading rate was observed between single-hand carrying and front-pack carrying (P = 0.051). The time to peak vertical ground reaction force at heel contact was significantly shorter during front-pack carrying compared with single-hand carrying (P = 0.03). Conclusion Single-hand bag carrying is associated with a significantly greater loading rate compared with single-shoulder and backpack carrying. Given that these impact forces are applied at every heel strike during walking, minimizing single-hand bag carrying may help reduce repetitive mechanical loading.