University of Tehran PressSport Sciences and Health Research2981-020510220190220A Comparison of Feed-Forward Activity of Selected Ankle Muscles between Active Collegiate Girls at the Risk of Ankle Sprain and Healthy Girlsمقایسه میزان فعالیت فیدفورواردی منتخبی از عضلات مچ پا در دختران فعال دانشگاهی در معرض خطر آسیب اسپرین مچ پا با دختران سالم1471667273010.22059/jsmed.2019.225207.793ENZahraRaghiPh.D. in Corrective Exercises and Sport Injury, Department of Sport Sciences, Sistan & Baluchestan University, Zahedan, IranMohammad HossienAlizadehProfessor, Department of Sport Medicine, Faculty of Physical Education and Sport Sciences, University of Tehran, Tehran, Iran0000-0003-1507-6502HoomanMinoonejadAssociated Professor, Department of Sport Medicine, Faculty of Physical Education and Sport Sciences, University of Tehran,
Tehran, Iran0000-0001-5417-8160RezaRajabiProfessor, Department of Sport Medicine, Faculty of Physical Education and Sport Sciences, University of Tehran, Tehran, Iran0000-0002-0464-5688Journal Article20170121The high incidence of ankle sprain, early resignation from sport and related disabilities have attracted the attention of researchers to identify and control those factors influencing the risk of this injury. The aim of this study wasto compare feed-forward activity of selected muscles of the ankle between collegiate active girls at the risk of ankle sprain and healthy girls.For this purpose, 32 active female students of physical education without a history of ankle sprain were divided into two groups (each group 16 subjects) including group at risk of ankle sprain (with less balance) and healthy group purposively and based on dynamic balance test scores (Y test). The feed-forward activity of muscles was evaluated by electromyography during jump-drop landing. The data were analyzed using multivariate analysis of variance (MANOVA) at <em>P</em>≤0.05. A lower feed-forward activity of peroneus longus and soleus muscles was observed in the group of at risk of ankle sprain (lower balance) when compared with the control group (<em>P</em>˂0.05). Probably, lower activity of these muscles in subjects with less balance could endanger the stability of the ankle and put them at risk of ankle sprain.https://sshr.ut.ac.ir/article_72730_23fa930e0a5342bb3bc1ec9754e237b5.pdfUniversity of Tehran PressSport Sciences and Health Research2981-020510220190220The comparison between onset activity of lumbo-pelvic and peroneal muscles in elite female Taekwondo players with and without functional ankle instability during single-leg drop landingمقایسه زمان شروع فعالیت عضلات کمری لگنی و پرونئال در تکواندوکاران نخبه زن با و بدون بیثباتی عملکردی مچ پا حین فرود تک پا1671837225010.22059/jsmed.2018.216821.770ENMonaMirjaniMSc, Department of Corrective Exercises and Sport Injury, Faculty of Physical Education and Sport Sciences, University of Tehran, Tehran, IranFoadSeidiAssociate Professor, Department of Sport Medicine, Faculty of Physical Education and Sport Sciences, University of Tehran, Tehran, Iran0000-0002-4156-1539Journal Article20161231Ankle is the first body part that contacts the ground during daily activities. The common injury in ankle joint is the external sprain that involves the proximal joints and the damaged ankle itself. The aim of this study was to compare onset activity of lumbo-pelvic and peroneal muscles in elite femaletaekwondo players with and without functional ankle instability during single-legdrop landing. 13 players with functional ankle instability (age 21.23±1.36 yrs, weight 53.76±3.56 kg and height 166.46±4.84 cm) and 13 healthy players (age 20.92±1.25 yrs, weight 53.69±4.17 kg and height 166.92±5.00 cm) were purposively selected. The electromyography activity of erector spine, quadratus lumborum, gluteus medius and peroneus longus muscles was recorded during single-leg drop landing. In order to compare onset activity of muscles, multivariate variance analysis was used (<em>P</em>≤0.05).The results showed that players with FAI had significant latency at onset of erector spine, quadratus lumborum, gluteus medius and peroneus longus muscles activity in comparison with control group. Therefore, these players suffer from disorder in peroneus longus muscle activity in addition to latency of lumbo-pelvic muscle activation. This factor could be the cause of their recurrent injury.https://sshr.ut.ac.ir/article_72250_5108dc8a3961d30274ba119b37621ffd.pdfUniversity of Tehran PressSport Sciences and Health Research2981-020510220190220The Effect of Fatigue on Peak Vertical Ground Reaction Force in Women with Different Knee Alignments during Single-Leg Jump and Drop Landingاثر خستگی بر حداکثرنیروی عمودی عکس العمل زمین در زنان با راستاهای متفاوت زانو در پرش و فرود تک پا1851967224910.22059/jsmed.2019.210852.753ENRaanaMohammadzadeh AslMSc, Department of Corrective Exercises and Sport Injury, Faculty of Physical Education, Kharazmi University, Tehran, IranSeyed SadrodinShojaeddinAssociate Professor of Corrective Exercises and Sports Injuries, Kharazmi University of Tehran, IranJournal Article20161024Deviation from the standard alignment of knee joint may changes weight distribution procedure and therefore reduces the mechanical efficiency. Understanding the biomechanical changes resulting from these deformities during fatigue is an important step in the prevention of subsequent injuries. So, the aim of this study was to investigate the effect of fatigue on peak vertical ground reaction force during single-leg drop landing in women with genu varum, genu valgum and normal knee. 40 healthy female students of physical education and sport sciences with genu varum deformity (<em>n</em>=14), genu valgum deformity (<em>n</em>=14) and normal knee (<em>n</em>=12) participated in this study. Caliper was used to assess alignment of knee and the subjects were divided into three groups (genu varum, genu valgum and normal knee). Then, subjects performed single-leg drop landing from 50% of maximum sergeant jump onto the force platform. After the fatigue protocol, jump-drop landing task was measured and recorded again. Analysis of variance with repeated measures was used for within-group comparison. The peak vertical ground reaction force was not significant in women with different knee alignments (<em>P</em>=0.314) and also fatigue had no significant difference in this variable (<em>P</em>=0.479). According to these results, it seems that fatigue (according to the protocol in this study) could not change vertical ground reaction force in those subjects with different knee alignments which paves the way for further research with different fatigue protocols.https://sshr.ut.ac.ir/article_72249_bf21bbc39ab15e4d5f4317c3ec86e958.pdfUniversity of Tehran PressSport Sciences and Health Research2981-020510220190220The effects of feedback exercises on
peak vertical Ground Reaction force and Rate of Loading associated with lower extremity injury in landing after volleyball blocksتأثیر تمرینات بازخوردی بر اوج نیروی عمودی عکس العمل زمین و نرخ بارگذاری مرتبط با آسیب اندام تحتانی در فرود بعد از دفاع موفق و ناموفق والیبال1972117225210.22059/jsmed.2019.258996.901ENAnisRostamiMSc of Sport Injury and Corrective Exercises, Faculty of Physical Education and Sport Sciences, Kharazmi University, Tehran, IranAmirLetafatkarAssistant Professor, Department of Biomechanics and Sport Injury, Faculty of Physical Education and Sport Sciences, Kharazmi University. Tehran, Iran0000-0002-5612-8340MehdiKhaleghi TazjiAssistant Professor, Department of Biomechanics and Sport Injury, Faculty of Physical Education and Sport Sciences, Kharazmi University. Tehran, Iran0000-0002-3043-3961Journal Article20180528Female volleyball players are 2 to 10 times more likely than men to suffer from the injury of anterior cruciate ligament in motor patterns with decrease in repeated acceleration, landing, and rotation. The aim of the present study was to investigate the effect of 6 weeks of feedback exercises on thepeak vertical ground reaction force and rate of loading associated with lower extremity injury in landing after successful and unsuccessful defense in female university volleyball players. 32 female volleyball players (age range 18-24 years) were selected and randomly divided into feedback (<em>n</em>=16) and control (<em>n</em>=16) groups. The force plate was used to measure the peak vertical ground reaction force and the rate of loading in pretest and posttest. According to the findings, the significance levels were <em>P</em>=0.003 and 0.004 for the first and second peak of the VGRF in stick landing, <em>P</em>=0.005 and 0.012 in step-back landing, <em>P</em>=0.008 and 0.011 for the first and second ROL in stick landing, <em>P</em>=0.002 and 0.016 in the step-back landing. The results of this study showed that feedback exercises had positive effects on the prevention of injury in volleyball players through significant changes in the risk factors of anterior cruciate ligament injury. Therefore, it is suggested to use feedback exercises to reduce those risk factors associated with injuries of the anterior cruciate ligament and to have accurate retention and transfer of safe techniques during the exercise sessions to the competitions.https://sshr.ut.ac.ir/article_72252_eafcea742c814037b43a92ba4687830a.pdfUniversity of Tehran PressSport Sciences and Health Research2981-020510220190220The effect of a six-week core stability exercise training on the EMG activity, static and dynamic balance in mentally retarded teenage girlsتاثیر شش هفته تمرینات ثبات مرکزی بر فعالیت EMG، تعادل ایستا و پویا در دختران نوجوان کم توان ذهنی2132297225110.22059/jsmed.2019.257640.894ENKatrinAfshariMSc Student in Exercise Physiology, Payame Noor University, Karaj Branch, Karaj, IranMohammad RezaAsadAssociate Professor of Exercise Physiology, Payame Noor University of Tehran, Tehran, IranMajidGholipourAssistant Professor of Exercise Physiology, Sharif University of Technology, Tehran, Iran0000-0002-2281-4166Journal Article20180510Mental retardation is one of the most common mental disabilities that accounts for about 3% of the world population. The aim of the present study was to investigate the effects of a core stability exercise program on the electromyography activity, static and dynamic balance of mentally retarded adolescent girls. 24 mentally retarded female students (age range 15-17 yr) were divided into two groups: experimental (<em>n</em>=12) and control (<em>n</em>=12). The experimental group performed core stability exercises for 6 weeks. The selected exercises consisted of half sit-up, side plank and four lower abdominal strengthening exercises. The Stork (one-leg standing) and Y tests were respectively used to measure static and dynamic balance. The EMG system was used to evaluate the electromyography activities induced by maximum voluntary isometric contraction of the rectus abdominis and external abdominal oblique muscles. Dependent and independent t tests were used to analyze the data. The results indicated that the core stability exercises significantly improved the static and dynamic balance, and also EMG activity in experimental group compared with the control group (all <em>P</em><0.001). Therefore, the practical application of this protocol along with other training is suggested to rehabilitate and enhance performance in mentally retarded adolescent girls.https://sshr.ut.ac.ir/article_72251_6a51c16215f07ff55f10303b32cbc5e8.pdfUniversity of Tehran PressSport Sciences and Health Research2981-020510220190220The Effect of 8 Weeks of Balance Training on Upper Extremity Function and Functional Movement Screening Test Scores of Adolescent Volleyball Playersتاثیر 8 هفته تمرینات تعادلی بر عملکرد اندام فوقانی و نمره ی آزمون های غربالگری حرکت عملکردی والیبالیست های نوجوان2312467225310.22059/jsmed.2019.263540.911ENHamedArazzadehMSc Student in Physical Education and Sport Sciences (Sport Injuries &amp; Corrective Exercises), Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, IranAli AsgharNorastehProfessor, Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, IranAhmadEidi DahnehVolleyball coach, Master of Sport Physiology at Azad University, Tehran, IranJournal Article20181201Balance is one of the key components of performing motor skills. The aim of this study was to investigate the effect of 8 weeks of balance training on the upper extremity function and functional movement screening test scores of adolescent volleyball players. In this quasi-experimental study, 30 adolescent volleyball players in the league of Golestan province were randomly divided into 2 groups: experimental and control. At the beginning and at the end of the study, upper quarter test by Y balance device and Functional Movement Screening (FMS) test were used. Then, the experimental group performed 8 weeks (3 sessions per week) of balance training. The results showed that FMS test score, in-line lunge, deep squat, hurdle step tests and upper extremity function improved in the experimental group but no significant difference was observed in the control group. Also, shoulder mobility, straight leg raise, trunk stability push-up and rotary stability tests had no significant difference in experimental and control groups before and after the training. According to these results, coaches can use this training to prevent sport injuries and improve function.https://sshr.ut.ac.ir/article_72253_4b0a950944b7d38ef5459b4657003571.pdfUniversity of Tehran PressSport Sciences and Health Research2981-020510220190220The Relationship between Isometric Strength of the Lower Extremity Muscles and Incidence of Injuries in Lower Extremity in Young Football Playersرابطه قدرت آیزومتریک عضلات اندام تحتانی با میزان بروز آسیب های اندام تحتانی بازیکنان جوان فوتبال2472677225510.22059/jsmed.2019.263851.912ENParisaNamaziMS Sport Injury and Corrective Exercises, Faculty of Sport Sciences, Shahid Beheshti University, Tehran, IranMostafaZareiAssociated Professor, Health and Rehabilitation Department, Faculty of Sport Sciences, Shahid Beheshti University, Tehran, IranFariborzHovanlooAssistant Professor, Health and Sport Rehabilitation Department, Faculty of Physical Education and Sport Sciences, Shahid Beheshti University, Tehran, IranJournal Article20181201The risk of injury in football is high. Many researchers have introduced muscle strength as one of the most important internal risk factors, but few studies have examined the relationship between the isometric strength of muscles and incidence of injuries. Therefore, the aim of this study was to examine the relationship between isometric strength of lower extremity muscles and the incidence of injuries in football players and the power to predict these injuries. The sample of this study included 73 football players under 21 years of age. Before the beginning of the season, the anthropometric dimensions and isometric strength of lower extremity in dominant leg of each player were measured by Isokinetic device (Biodex system 4), then each player was followed up for 8 months and their injuries were recorded. The results of Cox regression test showed no significant relationship between isometric strength of the measured muscles and the incidence of injuries in lower extremity. According to these results, it is suggested that medical and technical staff of football teams use isometric tests to identify high risk players. Other strength evaluation methods such as isokinetic and isotonic strengths may be more effective.https://sshr.ut.ac.ir/article_72255_3e8de7d56f23711b02be319cce318a7e.pdf