Showing 278 results for Type of Study: Research
Mr Nemat Allah Behboodian, Mr Jamal Khajeh Ali, Dr Amir Letafat Kar,
Volume 15, Issue 14 (10-2017)
Abstract
Due to the necessity of screening injury the aim of this study was to screen the scores of Functional movement screening tests in active and inactive subject . The study population consisted of University Students aged 18 to 25 years out of which 50 students (25 active and 25 inactive) were selected. Functional Movement Screen by Cook were used for functional screening. After the normality of the overall scores for FMS, Independed-Samples T-Test was used in SPSS (version 16) to analyze the data at significant level of 0/05. According to the findings, overall scores of FMS was significantly different between active and inactive subjects (P=0/001). Cut-off point of 17 was obtained for all subjects. There was no significant difference in shoulder mobility and straight leg raise test scores in the active and inactive people but there was significant difference among the scores of other five tests This prospective study shows that due to the overall score FMS inactive people than in active people are more prone to injury.
Zahra Khadivi Burojeny, Hamid Rajabi, Mohammad Marandi, Shaghayegh Haghjoo, Alireza Khadivi Burojeny, Ebrahim Noorian,
Volume 16, Issue 15 (9-2018)
Abstract
The purpose of present study was to determine the effect of 8 weeks of resistance training on serumic myostatin, and Fibroblast Growth Factor-2 (FGF-2) level in male Wistar rats. 20 adult male wistar rats(150-250gr) were randomly divided into 2 groups [control group; n=10 (C), resistance training; n=10 (R)]. Resistance training was conducted for 8 weeks (5 session/week) on a special 1 meter height ladder (divided by 26 stairs) with loading of 30٪ of body weight (suspended from the tail) in the first week and increased to 200٪ of body weight in the last week. Training includes 3 sets of 4 reps with 3 minutes rest between sets. At the end of last week blood samples were taken from the rats and myostatin, TGF-β1 and FGF-2 was measured in three groups with the ELISA kit. At the end of the study ،the plasma levels of the myostatin decreased [71/82±19/62 mg/dl (R) ver. 105/86±17/49 mg/dl(C). (p≤0/001)], but the level of FGF-2 increased significantly in resistance training group [102/462±11/135mg/dl (R) ver. 86/96±12/606 mg/dl (C) (p=0/048)]. In contrast, the serum level of TGF-β was not statistically different between the two groups [153/48±54/09 mg/dl (R).160/62±32/85 mg/dl (C). (p=0/725)]. This study shows that 8 weeks of resistance training reduces serum levels myostatin and increased serum levels of FGF-2. These two factors cause activation or non-activation of satellite cells (Muscle stem cells that control muscle hypertrophy). However the nerve - muscle agents in the first 8 weeks of resistance training have the maximum participation on strength increases, but in this research we see affect the signals of satellite cells in the first 8 weeks of resistance training can change significantly. Also, although serum levels of TGF-β1 in the exercise group was significantly different from the control group, but the overall value of the exercise group had slightly reduced.
Vahid Fekri Kourabbaslou, Pezhman Motamedi, Sadegh Amani Shalamzari,
Volume 16, Issue 15 (9-2018)
Abstract
Eotaxin, a pro-inflammatory Adipokine is secreted from adipose tissue, which its secretion increases in the obesity and cause neurodegeneration. BDNF is a neurological factor that interferes with cognitive function, fat and sugar metabolism, as well as the pathophysiology of obesity and metabolic syndrome in adulthood. The aim of this study was to investigate the Effect of Six Weeks of Interval Resistance Training on Eotaxin and Brain-Derived Neurotrophic Factor Serum Levels in Overweight young men. Twenty non-active students without regular exercise program from Kharazmi University were randomly selected and divided into two groups of training (n=10) and control (n=10). The training group performed Interval resistance Training for 6 weeks, 3 sessions per week and each session lasted 45 minutes. The training program included 7 moves with intensity of 30-40% of 1RM and velocity 2v for 10 seconds and rest intervals with intensity 30-40% 1RM and velocity v for 20 seconds. Blood samples were taken before and after 6 weeks of training to evaluate the serum Eotaxin and BDNF levels using the Sandwich ELISA. To analyze the data, the covariance test and Bonferron's post hoc test were used to compare the variables. The results of covariance analysis and Bonferroni test showed that 6 weeks of Interval resistance training caused a significant reduction in the weight (p=0.003), body mass index (p=0.004) Waist circumference (p=0.012) and fat percentage (p=0.001). Also, significant increase was observed in muscular endurance (p=0.001), serum BDNF levels in the training group compared to the control group (p=0.024), and serum Eotaxin levels in the training group decreased significantly (p=0.022). Correlation results showed a significant reverse relationship respectively between pre and post training Eotaxin and BDNF (p=0.015 r=-0.511, p=0.013 r=-0.586). Weight loss through six weeks of Interval Resistance training, which accompanied the loss of adipose tissue; resulted in a reduction in serum levels of Eotaxin and increased serum levels of BDNF.
Chiman Alyarnezhad, Hasan Daneshmandi, Nader Samami,
Volume 16, Issue 15 (9-2018)
Abstract
The upper cross syndrome is a postural abnormality with excessive activity of the muscles on the chest and upper trapezius muscles. In this study, upper cross syndrome in hearing impairment, vision impairment, and normal students is investigated. This descriptive- analytic study was performed on 30 poor vision boys, 30 poor hearing boys and 30 normal boys with mean age 11.76±2.89 years and their height was 135.15±13.13 cm, weight: 52±29.47 kg. Photos of each person were examined in sagittal planes for head and shoulder deviation. Flexible ruler(r=0/91) was used for the assessment of kyphosis. One-way ANOVA and scheffe post hoc test was used to compare groups by using SPSS (version 20) software (detection limit p≤0.05). Data analysis showed a significant difference between members of groups in case of forward head, rounded shoulder and kyphosis. Visual and hearing impairment is due to position abnormalities. Preventing and improving of the position forward head, rounded shoulder, and kyphosis lead to an abnormality postural position which is called the upper cross syndrome and it is conceivable with design and implementation of corrective exercises.
Razie Yaqoubi, Heydar Sadeghi, Ali Yaqoubi,
Volume 16, Issue 15 (9-2018)
Abstract
Since the anthropometric and biomechanical parameters role is effective in improving the quality of sports skills, researchers and sports scientists are interesting to identify and communicate between these factors. The purpose of this study was making relationship between some of anthropometrical and biomechanical parameter of girl swimmers in swimming breast strokes. Twenty girl Swimmers (mean±SD: age 12±2 years; heights 147.50±11.23 cm; weights 39.53±9.58 kg) performed in this study. After compeletting the personal and satisfaction form anthropometric charactrastics, motion domain, power swimmer’s record along with information about the number of arm and leg kicks in distance of 25 meters was measured. Descriptive statics (mean, Standard deviation) and deductive statics (pearson corrolation, principle component analysis (PCA) to the determine the main parameters influencing and multiple regression to determine the role of main parameters selected) were used for data analysis. Results indicate the relationship between weight and length with swimmers stroke length in swimming breast stroke. Also there was a relationship between body type (endo morph, mezzo morph) with some of swimmers biomechanical parameters (speed, number of legs kicks, top power, hyper extension, motion domin of thigh). The given results indicate that there was a relationship between percentage of the anthropometric and biomechanical parameters in swimmers, and some of biomechanical parameters predictors of back and front crawl swimming in the same swimmer were different.
Mohamad Hadi Ghasemi, Mohamad Fashi,
Volume 16, Issue 15 (9-2018)
Abstract
The aim of present study was comparison of advanced physical fitness profile between Olympic soccer team members of Iran according to playing position. 29 Invited soccer players to the 17th national Olympic soccer team of Iran dispatched to 17th Asian Olympics Games, Incheon 2014 )mean age of 20.39± 2.01 yrs(, divided into five group of goalkeepers, defenders, midfield players, wingers and attackers according to playing position participated in the study. Body composition parameters (including body mass index, body fat percentage), isokinetic force (peak torque, agonist/antagonist ratio, work fatigue, total work of extension and flexion), aerobic power by analysis of respiratory gases and anaerobic power and fatigue index by Wingate test were packaged for data collection. Descriptive statistics (i.e., mean ± standard deviation) and inferential statistics (i.e., one way ANOVA with Hopkins post hoc after subtracting data of pre- post) used for analysis data. While it was unbelievable the findings did not show any significant difference between five groups of present study. It seems that Olympic soccer team players of Iran has not prepared in a conditioning principle and based on playing position for participate in 17th Asian games. Moreover it supposed that national players spent most of the preparation periods & specific based conditioning workouts on their clubs, hence due to the short time of conditioning in the national camps trainings, players have not dispatched to the games with favorable preparation.
Mansour Eslami, Mohsen Nazari,
Volume 16, Issue 15 (9-2018)
Abstract
All sustained physical activities subject the body to various levels of fatigue. This is especially evident when running, which is one of the most popular forms of exercise and may be described as a reduction in maximum force production and power output . the purpose of this study was to investigate the effect of running in an exerted state on knee muscles power absorption and work during the stance phase of running. Sixteen healthy physical education male students with an average age 22 and SD 2.27 years and height 177 and SD 5.47 cm and mass 72.6 and SD 8.4 kg participated in this study voluntary. Kinetic and kinematic data recorded by using of video camera and force plate. The negative and positive power and work of muscles operating on knee has calculated using inverse dynamic equations in MATLAB2010 Software. Paired sample T test was done to statistical analysis in SPSS 2010 software (p≤0.05). The results of this study indicated that negative peak power and work significantly decreased 33.78% and 22.6% respectively. Although the positive peak power significantly decreased (p≤0.05), positive work didn’t change significantly (p=0.644). The results of this research indicated that the absorbing function of the muscles is decreased following fatigue and may be led to increase the injury risk of running.
Majid Jalili, Farzad Nazem, Akbar Sazvar,
Volume 16, Issue 16 (12-2018)
Abstract
Aerobic power (VO2max) is an important indicator of the health and physical fitness. Executive problems in direct VO2max measurement has led to developing sub-maximal aerobic power prediction equations. The purpose of present study was to develop native aerobic power prediction equation based on 6-Minute Walk Test (6MWT) and body composition indices in children. In 192 healthy children (8 to 12 years) VO2max was objectively measured by Bruce treadmill protocol with gas analysis. The 6MWT was performed according to ATS guidelines. Also, anthropometric measurements were measured according to standard methods. Multiple regression analysis was used to design aerobic power (ml/kg/min) prediction equation. Accuracy of native VO2max prediction equation was assessed by Pearson correlation and Bland-Altman approach between measured and predicted VO2max. Significant correlation was observed between direct VO2max and independent variables (r=0.25-0.734). Aerobic power of the boys could be predicted by weight and 6MWT according to the following equation: VO2max(ml/kg/min)= 5.359 + (0.067 × 6MWD m) – (0.286 × Weight kg) (r2=0.743, SEE=2.74 ml/kg/min, p≤0.001). Strong correlation was observed between measured and predicted VO2max (r=0.861, P≤0.001). In addition, Bland and Altman plots demonstrated a high degree of consistency between measured and predicted VO2max. Exercise and fitness coaches by utilization of native aerobic prediction equation based on the 6MWT and weight could be able to assess the aerobic power of the boys and to evaluation of the effects of exercise training on cardio-respiratory fitness.
Majid Mardaniyan Ghahfarrokhi, Abdolhamid Habibi, Hamed Rezaei Nasab,
Volume 16, Issue 16 (12-2018)
Abstract
Vitamin C consumption is important in Iron absorption. Therefore, the purpose of this study was to investigate the effect of acute aerobic activity after two weeks vitamin C supplementation on Iron status and hematological indices in club football players. In this quasi-experimental study, 40 club football players from Khuzestan province were randomly divided into two groups of vitamin C and placebo. Daily and for 14 days, subjects received 400 mg vitamin C in vitamin C group and 400mg dextrose in placebo group. 48 hours after the end of supplementation, a Bruce test was performed. To measure Iron, Ferritin, RBC and Hb levels, four blood samples were taken from the subjects, before and after the supplementation, immediately after and 72 hours after the Bruce test. Repeated measure ANOVA and Two way analysis of variance was used. 2 weeks of vitamin C supplementation showed a significant increase in RBC (p=0.026), Hb (p=0.041), serum Iron (p=0.008) and serum Ferritin (p=0.004) compared to placebo group. After aerobic exhaustive activity, RBC (p=0.034), serum Iron (p=0.023) and Ferritin (p=0.031) in vitamin C group significantly decreases compared to placebo group. After 72 hours of recovery, the vitamin C group showed a significant increase in serum Iron (p=0.036) and Ferritin (p=0.045) compared to placebo group. It seems that two weeks of vitamin C supplementation can improve the serum Iron, Ferritin, RBC and Hb profile of professional footballers before aerobic exhaustive activity and in recovery.
Mohadse Salehi Sarbizhan, Amir Letafatkar, Mehdi Khaleghi,
Volume 16, Issue 16 (12-2018)
Abstract
The most common side effect of physical activity is the risk of musculoskeletal damage, that anterior cruciate ligament injury is the most common one. Purpose of the study is comparing the effect of six weeks of comprehensive injury prevention training on anterior cruciate ligament with internal and external feedback on the proprioception and knee function of active female university students. Forty five active female university students aged 18-25 years were volunteered and randomly assigned to three groups (internal, external and control) and they performed the protocol three times a week for six weeks. Proprioception and function of the knee joint were measured using goniometer and functional tests in two stages namely pre-test and post-test. Statistical analysis of covariance, paired t test and Tukey's post hoc tests were used for statistical analysis with a significant level of p≤0.05. Overall results of the study showed that the present exercise protocol with internal and external feedback had a significant effect on the proprioception of p≤0.001 and p=0.000 for the knee performance and there was no significant difference between the two training groups. Regarding the results of the study, it is suggested that the present training protocol be addressed by coaches and sport sciences specialists as a complementary tool and method, along with other training methods, for those who are prone to damage to the anterior cruciate ligament.
Akram Arzani, Shadmehr Mirdar,
Volume 16, Issue 16 (12-2018)
Abstract
The aquaporin5 (AQP5) is an integral membrane protein that plays an important role in maintaining water homeostasis in the lung during of puberty. The purpose of this study was to evaluate the effect of period of reduced training with Nigella Sativa (NS) supplementation on AQP5 levels in the lung of Male Wistar rats during of puberty. 110 newborn three-week old male Wistar rats with average weight of 68±9 gr, were randomly divided into three groups included; the base, control and training groups. After a 6-week training period, the control group was divided into 2 groups with and without NS and training groups were divided into 6 groups including frequency, volume and intensity taper with and without NS. After 6 weeks, NS supplements were fed daily by gavages to groups of NS 500 mg/kg body weight. Progressive interval training was performed in 6 sessions, 30 minutes each session at a speed of 15 to70 meters per minute, Then, taper phase for three weeks in decreasing pattern, intensity, frequency and volume were performed. AQP5 levels were measured by ELISA methods. Analyzed is done with two-way ANOVA and LSD test at α≤0.05. While NS supplementation were increase average AQP5 levels in the taper groups of frequency, volume and intensity, But, there were no significant differences (P≥0/45) between AQP5 levels in with and without NS groups. Furthermore, three-week taper versus two weeks taper a significant increase the average AQP5 levels in the groups of with and without NS. It is suggested that the antihistaminic and antinociceptive effects of the NS with a period of reduced training with increasing levels of AQP5 would improve the physiological and functional parameters of the lung during of puberty.
Seyed Hossein Hosseinimehr, Mehrdad Anbarian,
Volume 16, Issue 16 (12-2018)
Abstract
The purpose of this study was to compare the effect of shoulder abduction angles, dominant and non-dominant arm and external loading on co-contraction ratio during arm abduction in scapular plane in overhead athletes and non-athletes. 10 swimmers, 10 handball players and 10 tennis players and ten non-athletes voluntarily participated in this study. Electromyography activity of shoulder muscles (middle and anterior deltoid; upper, middle and lower trapezius; infraspinatus, serratus anterior and latissimus dorsi) during dynamic and static arm abduction in 3 different angles (0-45º in 1second and holding it for 3 seconds, 0-90º in 2 seconds and holding it for 3 seconds, 0-135º in 1 second and holding it for 3 seconds) was recorded for dominant and non-dominant arm in loading and non-loading conditions. Co-contraction ratio of shoulder muscles was calculated for both groups. Findings indicated external loading, shoulder dominance and abduction angles had significant effect on shoulder muscles co-contraction ratio during (0-45º, 0-90º, 0-135º) and holding shoulder elevation in scapular plane (45º, 90º, 135º), also there was significant difference in shoulder muscles co-contraction ratio among four groups during and holding elevation in scapular plane (p≤0.05). Significant differences in shoulder muscles co-contraction ratio among athletes group and between athletes and non-athletes may be related to sport demands and adaptation to exercises and extensive use of upper limb as well.
Elaheh Peymani, Gholam Ali Ghasemi, Mehdi Ghaderiyan,
Volume 16, Issue 16 (12-2018)
Abstract
Meningomyelocele after cerebral palsy is the most common congenital defects of the nervous system that impairs the functioning of many body’s structures. This study aimed to assess the effect of six weeks selected physical training on balance, postural control and lower limb function in children with Meningomyelocele. In this quasi-experimental study, 10 boys aged 10-11 years with Meningomyelocele in L4-L5 levels that independently able to stand and take at least 5 steps were selected and after obtaining written consent from the parents, placed in an experimental group. Before and after 6 weeks (four 60-minute sessions per week) participation in a researcher-designed exercise protocol, Static and dynamic balance (Balance Scale PBS), postural sway (foot pressure device), neck craniovertebral angle and knee and hip range of motion (goniometer), thoracic arch angle (flexible ruler) and trunk and knee extensors strength (dynamometer) were measured. Data by t-test in SPSS 22 software was analyzed (p≤0/05). The results were showed significant difference between pre-test and post-test in all variables except the total index of postural control and trunk extensors strength (P≥0/05). Due to the effectiveness of the used exercise protocol, this protocol can be used to improve the postural control, balance and lower extremity function in rehabilitation of patients with Meningomyelocele and similar to those.
Mohammad Reza Mahmoudkhani, Hooman Minoonejad, Reza Rajabi, Amir Hossein Barati,
Volume 16, Issue 16 (12-2018)
Abstract
Judo is one of the most popular martial arts in the world. Researchers reported a higher risk of injuries during training rather than the time of competition. So, the safe and effective training methods should be considered. As development and application of injury prevention approaches and athletic performance enhancement is necessary, the purpose of this study was to investigate the effect of 8-week Judo Specific Functional Training on the injury risk factors and athletic performance in non-elite male judokas. 46 non-elite judokas participated in this study. Subjects were randomly divided into two groups of experimental (23:N) and control (23:N). For a period of 8 weeks, the experimental group attended a special judo functional training program designed by the researchers. At the same time, the control group participated in the usual judo training program presented by the coaches. The exercises were performed 3 sessions per week and 90 minutes per session. The subjects participated in pre- and post-tests. After data collection, in order to approve data normality and compare the variables, Shapiro-wilk, ANCOVA analysis was implemented at the significant level (p≤0.05) using SPSS version 21. The results showed that scores of functional movement screening (p=0.001), upper extremity Y balance test (p=0.001), vertical jump (p=0.001) and special judo fitness test (p=0.001) significantly increased among the experimental group in comparison to the Control group. This Judo specific functional training program simultaneously modifies or decreases the injury risk factors and improves the athletic performance and has more efficiency and effectiveness rather than the usual judo training program.
Mehdi Soltani Ichi, Pezhman Motamedi, Hamid Rajabi,
Volume 17, Issue 17 (4-2019)
Abstract
The purpose of this research was to determine the acute effects of plyometric training with changing of height landing on the electromyographic activity during preparatory phase land-jump in male students. The population of this research were 10 physical education male students of Kharazmi University, which selected as sample. (21/10±1/286yrs, 173±6/467 height, 68/2±7/42 weight). In four different days subjects Performed as single leg one of four protocols plyometric training and land - jump from a height of 40 and 60 cm. EMG activity of the quadriceps and hamstring muscle group 150 milliseconds before foot contact with the ground was recorded. Analysis of variance with repeated measures and Bonferroni post hoc test was used. The results of this study showed that muscle activity after changing of height landing in preparatory phase (from 40 to 60 cm) has increased significantly (P=0/002, P=0/001, P=0/001) respectively. Activity of muscles (rectus femoris, vastus lateralis, biceps femoris) during landing after performing plyometric and changing of height landing in preparatory phase has increased significantly (P=0/039, P=0/001) (P=0/006, P=0/000) (P=0/001, P=0/014) respectively. Jump height has increased significantly (P=0/007, P=0/002) respectively. The results showed that acute perform plyometric training with changing of height landing result in significant changes in the electrical activity of muscles and also the height of the jump in the preparatory phase.
M Naghibi,
Volume 17, Issue 17 (4-2019)
Abstract
Osteoporosis is characterized by low bone mineral density resulting into an increased risk of fracture (9). The aim of the study is determine the effect of aerobic exercise with blood flow restriction (BFR) and vitamin D supplementation on ostosis metabolic markers (OMM) among middle aged females. In this study 30 females with age of 42.76±7.44, height of 157.90±5.74, weight of 70.55±9.68 and BMI of 28.33±3.87, divided in three groups of 10 subjects, randomly. Two empirical Groups with and without BFR, both with vitamin D supplementation, one hour before training, performed aerobic exercise during eight weeks, three days a week, one hour a day, with 50 - 70% intensity of maximal heart rate. Density of OMM, calcium, phosphorous and alkaline phosphate examined in lab, 48 hours before and after training period in saving status before breakfast. Aerobic power of empirical groups determined with 12 minutes run/ walking cooper test. For data analysis used descriptive statistics, ANOVA and analysis variance with repeated measures. Results showed that eight weeks exercise with BFR and vitamin D supplementation, the density of calcium and phosphorous increased significantly. The density of Alkaline - phosphate did not show variation significantly. In the other hand, only the rate of calcium showed variation significantly, which increased in without BFR more than others. In conclusion, aerobic exercise with and without BFR and vitamin D supplementation can increase the density of OMM, calcium, phosphorous and alkaline- phosphate. But only the density of calcium showed increasing significantly.
Mohammadhossein Noori, Heydar Sadeghi,
Volume 17, Issue 17 (4-2019)
Abstract
Using appropriate devices and scientific methods can accelerate the process of sport talent identification and development to achieve championship level, and could also provide condition in which capable and talented athletes obtain highest level performance rapidly, so they will have long life championship. Former researches in scope of sport talent identification usually have been done in order to determine or normalize effective parameters. The purpose of this study was to design football talent identification algorithm based on fuzzy logic which classifies the football athletes. Due to expert opinion, essential parameters of football talent identification which also used in this software are; Cardio respiratory capacity (Physiology), Agility (Ability of motion), Dribble (technical skill) and Motivation (psychology). Norms of elite football player teenagers (14-16 yrs) are also used as index. Then with considering parameters and index, a fuzzy algorithm is designed which classifies football players in Unmatched, Semi-matched, Matched, Brilliant and Rare class. These results can help trainers and coaches in order to select talented and capable football players. In validation and reliability, records of elite junior Brazilian and Portuguese soccer have compared with norms of Iranian elite soccer.
H Arazzadeh, A.a Norasteh,
Volume 17, Issue 17 (4-2019)
Abstract
Although to improve balance and grasp the proprioception, recommended balance exercises, but there is not clear mechanism for the effectiveness of equilibrium training on healthy subjects. Suitable interaction of varios system of body and environment are necessary to maintain of the balance. Balance exercise is prescribed to improve balance and proprioception. There is not clear mechanism about the effectiveness of these exercise on healthy subjects. So The purpose of this study was to the Effect of 8 weeks of ankle-specific balance training on the balance and knee and ankle proprioception of adolescent volleyball players. the statistical sample of this study was 30 adolescent volleyball players in the league Golestan Which were selected as accessible and were randomly assigned into experimental and control groups. The experimental group performed 8 weeks and 3 sessions per week of ankle-specific balance. The results showed that there was a significant difference in the mean of balance and errors in reconstructing the angles of knee and ankle after exercise in the experimental group, while in the control group it was not significant. Results of this study showed that Balance Training can improve balance and proprioception in the knee and the ankle.
N Boroushak, H Khoshnoodi, H Daneshmandy, M Eslami,
Volume 17, Issue 17 (4-2019)
Abstract
Nowadays there is no specific and effective standard for evaluating the helmets in martial arts which it has caused a lot of brain damages. The purpose of this study was designing and modeling a helmet assessment machine in martial arts, based on dynamic’s parameters and criteria. SolidWorks, Adams and Catia softwares were used for designing this machine. Also, In order to build this machine, an artificial head that equipped with force and acceleration sensors and a mechanical arm for applying impact to the head were used. The validation of the machine was done by comparing its results (impact force, linear acceleration and rotational acceleration) with the results obtained from the simulated model in the computer. The Pearson correlation coefficient of 0.9 that obtained from this comparison indicates that the results of this machine are correct. To confirm the reliability of the machine, an Intraclass Correlations was used, the results showed values of 0.7 and greater than that and it also confirmed the appropriate repeatability of the machine. According to the results of this study, due to the considering the important parameters of linear and rotational acceleration and the impact force in evaluating helmets and investigating the mechanism of head injury in the conditions close to competition ones, the device can be an appropriate equipment for more accurate measurement of helmets in martial arts.
Sh Lenjannejadian, J Reisi,
Volume 17, Issue 17 (4-2019)
Abstract
Balance is a complex concept, especially when one wants to do complex motor skills. Therefore, the balance during activity is more important than the static and dynamic balance that is performed without the skill. The aim of this study was to introduce a new activity-based balance index of elite soccer players. 27 young soccer players (12-14 years) whom participated in Iranian premier league were selected. To assess their balance, activity and skill, four functional tests consisting one leg stance, dynamic Y balance, running and dribbling tests were administered. During these tests, besides their relative scores, the acceleration of body center was also recorded using an accelerometer and a new activity-based balance index (ABI) were calculated from these available data. The Results showed a significant positive correlation between ABI and both static and dynamic balance scores(r=0.6, p=0.002). Also, a significant negative correlation was found between ABI and dribbling scores(r=-0.45, p=0.026), which could be interpreted as the necessity of agility of the players. It could be concluded that this new activity-based balance index was found to be successful for evaluating both the balance and the skill level of soccer players.
