@article { author = {raghi, zahra and Alizadeh, Mohammad Hossien and minoonejad, hooman and rajabi, reza}, title = {A Comparison of Feed-Forward Activity of Selected Ankle Muscles between Active Collegiate Girls at the Risk of Ankle Sprain and Healthy Girls}, journal = {Sport Sciences and Health Research}, volume = {10}, number = {2}, pages = {147-166}, year = {2019}, publisher = {University of Tehran Press}, issn = {2981-0205}, eissn = {2981-0205}, doi = {10.22059/jsmed.2019.225207.793}, abstract = {The 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 P≤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 (P˂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.}, keywords = {Active girls,Ankle sprain,Electromyography,Feed-forward activity,Muscles of the ankle}, url = {https://sshr.ut.ac.ir/article_72730.html}, eprint = {https://sshr.ut.ac.ir/article_72730_23fa930e0a5342bb3bc1ec9754e237b5.pdf} } @article { author = {mirjani, mona and seidi, foad}, title = {The 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 landing}, journal = {Sport Sciences and Health Research}, volume = {10}, number = {2}, pages = {167-183}, year = {2019}, publisher = {University of Tehran Press}, issn = {2981-0205}, eissn = {2981-0205}, doi = {10.22059/jsmed.2018.216821.770}, abstract = {Ankle 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 (P≤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.}, keywords = {functional ankle instability,lumbo-pelvic muscles,onset activity,peroneus longus muscle,taekwondo}, url = {https://sshr.ut.ac.ir/article_72250.html}, eprint = {https://sshr.ut.ac.ir/article_72250_5108dc8a3961d30274ba119b37621ffd.pdf} } @article { author = {Mohammadzadeh Asl, Raana and shojaeddin, Seyed Sadrodin}, title = {The Effect of Fatigue on Peak Vertical Ground Reaction Force in Women with Different Knee Alignments during Single-Leg Jump and Drop Landing}, journal = {Sport Sciences and Health Research}, volume = {10}, number = {2}, pages = {185-196}, year = {2019}, publisher = {University of Tehran Press}, issn = {2981-0205}, eissn = {2981-0205}, doi = {10.22059/jsmed.2019.210852.753}, abstract = {Deviation 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 (n=14), genu valgum deformity (n=14) and normal knee (n=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 (P=0.314) and also fatigue had no significant difference in this variable (P=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.}, keywords = {fatigue,Genu valgum,Genu varum,single-leg drop landing,vertical reaction force}, url = {https://sshr.ut.ac.ir/article_72249.html}, eprint = {https://sshr.ut.ac.ir/article_72249_bf21bbc39ab15e4d5f4317c3ec86e958.pdf} } @article { author = {Rostami, Anis and Letafatkar, Amir and Khaleghi tazji, Mehdi}, title = {The effects of feedback exercises on peak vertical Ground Reaction force and Rate of Loading associated with lower extremity injury in landing after volleyball blocks}, journal = {Sport Sciences and Health Research}, volume = {10}, number = {2}, pages = {197-211}, year = {2019}, publisher = {University of Tehran Press}, issn = {2981-0205}, eissn = {2981-0205}, doi = {10.22059/jsmed.2019.258996.901}, abstract = {Female 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 (n=16) and control (n=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 P=0.003 and 0.004 for the first and second peak of the VGRF in stick landing, P=0.005 and 0.012 in step-back landing, P=0.008 and 0.011 for the first and second ROL in stick landing, P=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.}, keywords = {feedback exercises,ground reaction force,Rate of loading,Step-back landing,Stick landing,Volleyball}, url = {https://sshr.ut.ac.ir/article_72252.html}, eprint = {https://sshr.ut.ac.ir/article_72252_eafcea742c814037b43a92ba4687830a.pdf} } @article { author = {afshari, katrin and Asad, Mohammad Reza and Gholipour, Majid}, title = {The effect of a six-week core stability exercise training on the EMG activity, static and dynamic balance in mentally retarded teenage girls}, journal = {Sport Sciences and Health Research}, volume = {10}, number = {2}, pages = {213-229}, year = {2019}, publisher = {University of Tehran Press}, issn = {2981-0205}, eissn = {2981-0205}, doi = {10.22059/jsmed.2019.257640.894}, abstract = {Mental 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 (n=12) and control (n=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 P<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.}, keywords = {core stability exercises,Dynamic balance,EMG activity,mentally retarded adolescent girls,Statistic balance}, url = {https://sshr.ut.ac.ir/article_72251.html}, eprint = {https://sshr.ut.ac.ir/article_72251_6a51c16215f07ff55f10303b32cbc5e8.pdf} } @article { author = {arazzadeh, hamed and norasteh, ali asghar and eidi dahneh, ahmad}, title = {The Effect of 8 Weeks of Balance Training on Upper Extremity Function and Functional Movement Screening Test Scores of Adolescent Volleyball Players}, journal = {Sport Sciences and Health Research}, volume = {10}, number = {2}, pages = {231-246}, year = {2019}, publisher = {University of Tehran Press}, issn = {2981-0205}, eissn = {2981-0205}, doi = {10.22059/jsmed.2019.263540.911}, abstract = {Balance 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.}, keywords = {Adolescent,Balance Training,Screening tests,Upper Extremity Function,Volleyball Player}, url = {https://sshr.ut.ac.ir/article_72253.html}, eprint = {https://sshr.ut.ac.ir/article_72253_4b0a950944b7d38ef5459b4657003571.pdf} } @article { author = {namazi, parisa and zarei, mostafa and hovanloo, fariborz}, title = {The Relationship between Isometric Strength of the Lower Extremity Muscles and Incidence of Injuries in Lower Extremity in Young Football Players}, journal = {Sport Sciences and Health Research}, volume = {10}, number = {2}, pages = {247-267}, year = {2019}, publisher = {University of Tehran Press}, issn = {2981-0205}, eissn = {2981-0205}, doi = {10.22059/jsmed.2019.263851.912}, abstract = {The 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.}, keywords = {Football Injuries,Isometric Strength,Lower Extremity,Prevention of injuries,Risk Factor}, url = {https://sshr.ut.ac.ir/article_72255.html}, eprint = {https://sshr.ut.ac.ir/article_72255_3e8de7d56f23711b02be319cce318a7e.pdf} }