Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 6 3 2020 12 1 Comparative Analysis of Jumping and Landing Velocity of the Young Elite Spikers of the Iranian National Volleyball Team While Performing Block Jump 144 153 FA Ali Fatahi Department of Sports Biomechanics, Faculty of Physical Education and Sports Sciences, Central Tehran Branch, Isamic Azad University, Tehran, Iran. Razieh Yousefian Molla Department of Sports Biomechanics, Faculty of Physical Education and Sports Sciences, Central Tehran Branch, Isamic Azad University, Tehran, Iran. Mitra Ameli Setaregan-e-Salamat Gostar Technical Clinic of Training and Corrective Exercise, Tehran, Iran. Objective: Accurate velocity analysis is essential when performing the block jumping technique on the net by various spikers because it will improve this performance and prevent injury. This study aimed to compare the jump and landing velocity of the Iranian national team’s young elite spikers when performing block jump skills.  Methods: A total of 21 young elite male volleyball players of the Islamic Republic of Iran (11 wing spikers and 10 middle spikers) participated in the present study. Subjects performed block jumping skills. Force data in the X, Y, and Z directions were obtained directly from the force plate’s output. Then, the area under the force-time curve was calculated as an impulse. The rate of changes in mean, maximum, and minimum velocities and the resultant in each direction (X, Y, and Z) were obtained by dividing every subjects’ impulse data in each direction to his mass. Descriptive statistics, the Shapiro-Wilk test (checking the normality of data distribution), and independent t-test were used to analyze and compare the two groups’ variables (P≤0.05). Results: The difference between the mean velocities on the X and Z planes and the mean rates between the two groups was significant. The other velocity variables in the two groups were not significant (P˂0.05). Conclusion: The results of the present study can help coaches, players, and volleyball professionals to pay more attention to the velocity of execution during block jump technique, especially between middle and wing spikers in different directions during the match and design of the training program.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 6 3 2020 12 1 A Comparative Study of Plantar Arch Index, Weight Distribution, Equilibrium Performance, and Selected Musculoskeletal Disorders in Active and Non-active Adolescences 154 169 FA Ali Fattahi Departement of Sports Biomechanics, Faculty of Fports Sciences and Physical Education, Islamic Azad Uniuversity, Central Tehran Branch, Tehran, Iran. Haniyeh Zehtab Asghari Departement of Sports Biomechanics, Faculty of Fports Sciences and Physical Education, Islamic Azad Uniuversity, Central Tehran Branch, Tehran, Iran. Zahra Koreili Departement of Sports Biomechanics, Faculty of Fports Sciences and Physical Education, Islamic Azad Uniuversity, Central Tehran Branch, Tehran, Iran. Objective: musculoskeletal disorders cause the loss of beauty and decrease the mechanical performance of individuals. The functions of the steps on the floor are the attraction and distribution of forces and the provision of the body’s stability. The study aimed to compare arch index, weight distribution, balance, and selected musculoskeletal disorders in active and non-active adolescents. Methods: The sample consisted of 50 teenagers (28 active and 22 no actives) who were randomly targeted. The subjects demographics included the non-active adolescence with Mean±SD of Age: 12.46±1.10, Mean±SD of Height: 157.69±8.48 cm, and Mean±SD of Weight: 46.65±8.45; the active group with Mean±SD of Age: 12.26±1.13, Mean±SD of Height: 153.91±10.09, and with Mean±SD of Weight: 44.52±7.76. For statistical analysis of data, K-S test for normal distribution of data and used t-test to compare the two groups of active and non-active and U Mann–Whitney at the significance level of 0.05.  Results: The descriptive findings indicate that the mean musculoskeletal system in adolescences is more active than active. The independent t-test for comparing the balance performance among the active and non-active groups showed a significant correlation (P=0.04). Still, there was no significant difference in the foot index parameters and weight distribution.  Conclusion: Musculoskeletal diseases play a critical role in the mechanical function of individuals. The posture and balance performance in the active group was better than in non-active adolescences. Still, no difference was observed between the foot index and weight distribution in active and non-active juveniles. More complex research is needed to test this hypothesis.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 6 3 2020 12 1 Effect of Proprioception Training on Pain and Knee Joint Position Sense of Athletes With Genuvalgum 170 179 FA Mohammad Rahim Amiri Department of Sport Medicine and Health, Faculty of Physical Education and Sport Sciences, University of Tehran, Tehran, Iran. Masoud Golpayegani Department of Sport Pathology and Sport Physiology, Faculty of Sport Sciences, Arak University, Arak, Iran. Fariba Moradi Vastgani Department of Sport Pathology and Sport Physiology, Faculty of Sport Sciences, Arak University, Arak, Iran. Mohammad Mirghasemi Department of Physical Education and Sport Sciences, Faculty of Humanities, Borujerd Branch, Azad University, Lorestan, Iran. Objective: The purpose of this study, the effect of strengthening exercises on proprioception athletes with knee joint position sense in Genuvalgum. Methods: A total of 30 athletes with an age range between 20-30 years voluntarily participated in this study and were randomly divided into two groups (experimental and control) groups. Proprioceptive training program for experimental group for 8 weeks (3 sessions per week, 3 times daily, 20 minutes). The pre-test and post-test to detect the joint position (PFPPS) and the knee proprioception were measured via digital pictures using Auto-CAD software. Data analysis software SPSS V. 16 using paired t-test and one-way analysis of variance. Results Knee joint proprioception exercises can reduce the reconstruction error. Conclusion: These exercises improve proprioception in athletes with Genuvalgum.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 6 3 2020 12 1 Evaluation of Floor Pressure Distribution in Female Athletes With Tibial Internal Pressure Syndrome 180 189 FA Mojgan Rokninejad Department of Sports Science, Faculty of Sports Sciences, South Tehran Branch, Payame Noor University, Tehran, Iran. Seyyedeh Hanniyeh Hashemi Department of Sports Science, Faculty of Sports Sciences, Shoushtar Branch, Islamic Azad University, Shoushtar, Iran. Objective: Internal tibial pressure syndrome is one of the most common musculoskeletal disorders in athletes. Muscle imbalance in the dorsiflexor and plantar flexor muscles of the ankle in this syndrome may affect the distribution of plantar pressure in different parts of the foot. Therefore, the present study aimed to evaluate plantar pressure distribution in female athletes with tibial internal pressure syndrome. Methods: The statistical sample of this study, a comparative analytical study, consisted of 70 female athletes in the field of physical education in Tehran (including 35 subjects with tibial pressure syndrome and 35 healthy subjects in the age range of 18-22 years), which were randomly selected and purposefully selected. Plantar pressure values during walking between the experimental and control groups were assessed using a foot scan device in ten areas of the sole. The data of this study were analyzed using an independent t-test. Results: This study showed that the distribution of plantar pressure in the group with tibia internal pressure syndrome in 6 variables of the first toe, first metatarsus, second metatarsus, third metatarsus, midfoot, and heel was higher than the control group (P≤0.05). But the other measured variables of plantar pressure, which include the second to fifth toe, fourth metatarsus, fifth metatarsus, and the outer part of the heel, are not significant in both groups (P≥0.05). Conclusion: According to the results of this study, the hypothesis is supported that plantar pressure distribution may be higher in people with tibial internal pressure syndrome. This increase in plantar pressure can be due to excessive pronation of the ankle. Future studies should focus on the effects of therapies on reducing plantar pressure in people with the syndrome.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 6 3 2020 12 1 Comparison of the Effect of Strength Training With and Without Blood Flow Restriction on Motor Function in Active Females With Dynamic Knee Valgus 190 203 FA Seyyedeh Mahshid Hadavi Department of Sport Injuries and Corrective Exercise, Faculty of Physical Education and Sports Sciences, University of Guilan, Rasht, Iran. Parisa Sedaghati Department of Sport Injuries and Corrective Exercise, Faculty of Physical Education and Sports Sciences, University of Guilan, Rasht, Iran. Mohammad Mottaghitalab Department of Sport Biomechanics, Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, Iran. Objective: Dynamic Knee Valgus is a common risk factor for acute lower extremity injuries and overuse. Studies on new training methods to improve motor function and strengthen the knee and thigh joint muscles are also ongoing. The purpose of this study was to compare the effect of conventional resistance training with and without Methods: This study was quasi-experimental. The present study’s statistical population consisted of active women with dynamic valgus deformity of the knee in Chalous (Mazandaran Province, Iran) aged 18-28. Thirty-six women with dynamic knee valgus were purposefully selected as the research Participants. Subjects were evaluated for patellar orientation with a goniometer, static and dynamic balance through stork and y tests, and lower limb strength with the Sargent jump test. Subjects were randomly divided into three groups: control, conventional resistance training without restricting blood flow, and traditional resistance training restricting blood flow. They also gave training sessions for 8 weeks in three sessions per week. Results: The results showed a positive effect of exercise programs on static balance (P=0.001), dynamic balance (P=0.001), patellar alignment, and lower limb strength (P=0.001) in women with dynamic knee defects. Also, the results of covariance analysis showed a significant difference between control and training groups. Conclusion: The present study results show a significant effect of the strength training program with and without restricting blood flow on improving patellar direction, static and dynamic balance, and lower limb strength of active women. It seems that active women can use these exercise programs to improve performance and reduce injury risk.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 6 3 2020 12 1 Does Body Mass Index Affect the Symmetry Index Between Preferred and Nonpreferred Foot 204 213 FA Safoura Ghasemi Department of Sports Management, Faculty of Sports Sciences, Arak University, Arak, Iran. Nahid Adibnejad Department of Sports Pathology, Faculty of Sports Sciences, Arak University, Arak, Iran. Objective: The presence of symmetry between the superior and non-superior legs prevents muscle imbalance and leads to the prevention of sports injuries. Therefore, this study aimed to answer the question: Does body mass index affect the symmetry index between preferred and non-preferred foot? Methods: A total of 44 young girls were purposefully divided into two groups (Body Mass Index range of 25 to 30 as an overweight group and Body Mass Index range of 18.50 to 24.99 as a normal weight group) participated in this study. Subjects’ foot index data were recorded using a camera pedoscope while maintaining static balance. An independent t-test was used to compare the results between groups and paired t-test was used to compare the results within the group to examine the studied samples. Tests were analyzed at a significance level of 0.05 using SPSS software V. 24. Results: Results show symmetry index of the preferred and non-preferred foot of the overweight group ranged from 0.72 to 1.41 and in the normal group was 0.76 to 1.43, and the results were not significant (P>0.05). This means that the preferred and non-preferred foot of the subject had symmetry in both groups. Conclusion: The present study’s findings showed that body mass index does not affect the foot symmetry index. It is suggested that research be conducted to determine whether obesity influences the symmetry index.