Research in Sport Medicine and Technology

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Muscle imbalances in the shoulder are a weakness in the external rotator cuff muscles compared to the internal rotator cuffs, in which the weakness of the external rotator cuff muscles is a risk factor for volleyball players' shoulder injuries. Shoulder dyskinesis can be caused by imbalance of the scapula stabilizing muscles, which improves with muscle coordination the aim of this study was to investigate the effect of perturbation training on eccentric strength of external rotators and scapular kinematics. Twenty-four male volleyball players with a score of less than 30 on CKCUEST test participated in this study, which was randomly divided into two groups of experimental and control. The eccentric strength of the external rotator cuff muscles was measured using an isokinetic at 120 degrees per second. Scapular upward rotation also measured with a dual inclinometer at 45 °, 90 °, 135 ° and the end range of motion of the shoulder abduction. Comparing the experimental and control groups, a significant difference was observed in the shoulder external rotators eccentric strength. There was a significant difference only in 135 ° of scapular upward rotation. In other angles, no significant difference was observed between the two groups. The results showed the positive effect of perturbation training on the eccentric strength of external rotators and scapular upward rotation in arm abduction; therefore, coaches and volleyball players can be advised to add these exercises to their training programs to increase performance and prevent shoulder injuries.
 

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Background and purpose: Determining specific abilities and skills in volleyball players depends on the amount of anthropometric, physiological, biomechanics and psychological characteristics of the players in this field and is vital for improving the performance of sports skills in them. Since by comparing these important factors in the group of teenagers and young adults, it is possible to guide teenagers towards success factors in youth and adulthood, the purpose of this research was to compare the main characteristics of elite teenage and young male volleyball players.
Methods: 30 male members of the national youth volleyball team of the Islamic Republic of Iran (15 youths and 15 teenagers) were examined in terms of their main anthropometric, biomechanics, physiological and psychological characteristics with the aim of evaluating and determining the main components and comparing them.  In order to determine he main components of the evaluated indicators, first the PCA statistical method and then the independent t statistical method were used to compare the two groups(0.05≥p).
Results: Among the main indices of anthropometric, biomechanical, physiological and psychological characteristics, only the physiological index of maximum heart rate showed a significant difference between the two groups (0.05≥p).
Conclusion: It seems that the main differences of volleyball players in these two age groups are more related to experience in the game and mastery in the implementation of various skills and techniques, and all these main features can be found in the talent search process of this group of young people.
 

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Testosterone enanthate increases muscle growth and athletic performance but is associated with oxidative stress and tissue damage. This study aimed to investigate the effect of propolis on oxidative stress markers induced by testosterone enanthate in the kidney tissue of female Wistar rats undergoing resistance training. Twenty-two 8-week-old female rats, weighing 208.22±14.17 g, were randomly divided into three groups: 1) resistance training + placebo (n=6), 2) resistance training + testosterone enanthate (n=8), 3) resistance training + testosterone enanthate + propolis (n=8). The rats underwent an 8-week resistance training protocol involving ladder climbing (five days per week). Testosterone enanthate was administered at a dose of 20 mg/kg body weight per injection, and propolis was administered at a dose of 400 mg/kg body weight by gavage (each three times a week). The levels of superoxide dismutase (SOD), glutathione peroxidase (GPX), and malondialdehyde (MDA) in kidney tissue were measured by spectrophotometry. One-way ANOVA and Bonferroni post hoc tests were used for statistical analysis. The results showed that testosterone enanthate significantly decreased GPX and SOD levels and increased MDA levels. Propolis consumption led to a relative reduction in these oxidative stress markers, demonstrating its potential antioxidant effects.

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low back pain (LBP) is a significant issue and the aim of study was to compare two protocols, stretching exercises and combination of Pilates, regarding their effects on pain, disability, and electromyographic activity of core muscles in women with LBP.
This research employed a semi-experimental clinical trial design with pre-tes, post-test measures and a control group. Thirty women aged 20-35 with LBP were randomly assigned to three groups. Pain using a visual analog scale, disability using the Roland-Morris Questionnaire, and electromyographic activity was measured using bilateral electromyography. The experimental groups performed their exercises for 8 weeks, control group continued their regular daily activities.
Both protocols were effective in reducing pain and disability while increasing electromyographic activity of muscles. Analysis revealed significant differences in post-tests between the intervention groups and the control group. However, no significant difference was observed between the two intervention groups. The results means indicated a greater effect of the combination exercises compared to stretching exercises alone.
The results suggest that stretching exercises and a combination of Pilates are effective in reducing pain, disability and increasing electromyographic activity of core muscles in individuals with LBP. it is recommended to utilize these exercises for improving non-specific chronic LBP.
 

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Aim: One of the methods used to improve sports performance is the use of carbohydrate mouth rinse. The purpose of this study is to investigate the effect of carbohydrate mouth rinse on the specific performance of trained soccer players.
Methods: Eighteen professional football players (22 ± 2 years) were randomized into two groups of carbohydrate mouth rinse (CMR) and placebo (P) in a fasted state after eight hours of sleep. During the two main test sessions, players were provided with either a color- and flavor-matched carbohydrate drink or a no-calorie drink (placebo) for a mouth rinse in a double-blind randomized crossover design. Players were asked to rinse the carbohydrate solution in their mouth for 10-15 seconds and then return it to the plastic cup. Sprint performance, maximum height jump, and 30-15 intermittent fitness test (30-15 IFT) were taken from the subjects.
Findings: Carbohydrate mouth rinse increased running distance in 15-30 IFT test. While there was no significant difference between the two groups in the performance of the 30-meter speed test and the maximum vertical jump.
Conclusion: Therefore, those soccer players who are unable to drink carbohydrate solutions due to digestive problems are advised to use the carbohydrate mouth rinse way to improve their performance during the game.

 

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Introduction and purpose: The present study was conducted with the aim of investigating the effect of acute glutamine supplementation along with intermittent exercise on Hsp70 and blood lactate response of club football players. Methodology: 32 players of the Tehran Railway team were selected and randomly divided into four groups: control, supplement, supplement-sports activity, and sports-activity. Subjects participated in daily exercises before conducting the study, and only two complementary groups - sports activity and sports activity - performed the periodic protocol. Blood samples were taken at baseline, pre-test, post-test and 90 minutes after the test. The supplement and placebo were consumed in an amount of 0.5 g/kgBW and a volume of 5 ml/kgBW one hour before the periodic protocol. The interval protocol included 3 stages of 20-minute running with an intensity of 80% of the maximum heart rate and a 5-minute rest of walking between the stages. HSP72 and blood lactate levels were measured using ELISA and enzymatic methods, respectively. The data were analyzed using the analysis of variance test with repeated measures and the between-group factor at the P≤0.05 level. Findings: Glutamine supplement alone and together with exercise stimulate the response of HSP72 and the combination of supplement and exercise leads to a greater response of HSP72 and lactate changes did not play a role in this response. Discussion and conclusion: It seem that taking glutamine supplements in the long term creates more adaptations, which of course should be studied.
 

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The study aimed to investigate the impact of gait retraining using verbal feedback on pain and peak vertical ground reaction force in runners with patellofemoral pain syndrome, a common treatment and prevention method for the condition that involves modifying movement patterns to ensure knee joint stability. The current research was applied, and a semi-experimental study method with a pre-test-post-test design was used. The statistical sample of this research was made up of 20 runners with patellofemoral pain syndrome who were identified by a physiotherapist using the Clark test and were randomly divided into two control and experimental groups. The experimental group performed eight weeks of running and three sessions per week along with the walking retraining protocol with verbal feedback from the researcher, while the control group did not receive any intervention to their exercise. The variables studied in this research were the pain factor and the peak vertical ground reaction force, which were recorded respectively using a visual analog scale and a Bartek dynamometer with a sampling frequency of 1000 Hz in both pre- and post-test stages. The results of the the mixed analysis of variance test with repeated measurements showed that the interactive effect of time on the group was significant and, the gait retraining protocol by verbal feedback reduced pain (P=0.000) and the peak vertical ground reaction force in the experimental group (P=0.003). The existence of differences in pain variables and peak ground reaction force during running confirms the need to use different strategies in the training of athletes. It is suggested that trainers have a special look at the gait retraining approach by verbal feedback to correct the movement pattern while running, in rehabilitation, and specialized exercises.
 

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Introduction and purpose: The landing error scoring system is a valid and reliable tool for functional assessment of jump-landing movement. The aim of the present study was to investigate the effectiveness of sports training on the landing error scoring system in athletes.
Methodology: Searching between 2014 and 2024 from IranDoc, Magiran, PubMed, Google Scholar, SPORTDiscus, Scopus, PEDro and (ISI) Institute for Scientific Information databases using the combination of jump-landing keywords. Landing mechanics, landing kinetics and kinematics, injury prevention, training, rehabilitation and landing error scoring system were done. A total of 88 articles related to this field were found, after reviewing and screening through the inclusion criteria, 8 articles were reviewed in full text.
Results: Various exercises, including neuromuscular, suspension, knee injury prevention, fatigue and kinesiotype, have been used to be effective on the landing error scoring system test. As a result of corrective exercises and fatigue, the experimental groups showed an improvement and a decrease in the jump-landing movement performance in the landing error scoring system, respectively.
Discussion and conclusion: It seems that in order to prevent jump-landing movement errors and possible injuries caused by it, exercises should be done that, in addition to increasing concentration and coordination in movement, make athletes resistant to factors such as danger.
 

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Introduction: Patellofemoral pain is one of the most common orthopedic knee problems in runners. The Pose model is an instructor-led gait training program that aims to modify gait to reduce the risk of injury. Therefore, the aim of the present study was to investigate the immediate effect of modifying the running kinematic pattern using the Pose model on kinematic factors associated with patellofemoral pain in runners.
Materials and Methods: The present study was a field trial in which 20 healthy runners were divided into two groups: a control group and a gait retraining group using the Pose method. Running retraining was taught for 30 minutes, and lower limb kinematic variables including trunk angle, contralateral hip drop angle, dynamic knee valgus, knee flexion angle, and ankle dorsiflexion angle were recorded before and after the Pose intervention. SPSS20 software was used to analyze the data.
Results: The results of statistical analysis showed that using the Pose model can improve the running kinematic pattern, so that in the intervention group, the trunk angle on the right side (P<0.01) with an effect size of 0.656, the hip drop angle on the opposite side (P<0.01) with an effect size of 0.737,the dynamic knee valgus on the left side (P<0.02) with an effect size of 0.428 and on the right side (P<0.01) with an effect size of 0.583,and the maximum knee flexion angle on the left side (P<0.01) with an effect size of 0.746 and on the right side (P<0.01) with an effect size of 0.600.
Conclusion: retraining the running pattern using the Pose method as immediate feedback can affect the two-dimensional kinematics of the pelvic girdle and knee joints and improve their performance.
 

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The impact of maternal physical activity on offspring health and phenotypic changes due to exercise has emerged as a significant area of interest in exercise physiology in recent years. Therefore, the aim of this study was to determine the effect of a maternal high-intensity interval training (HIIT) program on the expression of PGC1α and SIRT1 genes in the skeletal muscle of first-generation offspring in Wistar rats. Twenty-four 8-week-old female Wistar rats were acclimatized to the environment and then divided into three groups: a maternal control group, a maternal pre-pregnancy exercise group, and a maternal exercise group that trained both before and during pregnancy. The pre-pregnancy exercise regimen lasted 6 weeks, while the exercise during pregnancy lasted 3 weeks. The exercise protocol involved treadmill running, consisting of 5 days per week, with each session including 1 minute of running at 85-100% of VO2peak and a 10% incline, followed by 2 minutes of rest at 65% of VO2peak and 0% incline. The number of intervals started at 10 and increased based on the overload principle. The control group remained sedentary during this period. After the exercise period and the birth of the offspring, male offspring were categorized according to their maternal groups, and the expression levels of PGC1α and SIRT1 genes in their skeletal muscle were evaluated at 10 weeks of age. Data were analyzed using ANOVA and Tukey's post-hoc test.
The results indicated that after the 6-week HIIT program, both the pre-pregnancy exercise group and the group that exercised before and during pregnancy showed significant differences in speed and distance in the functional performance test compared to the control group (P < 0.05). Additionally, significant differences were observed in the expression of PGC1α and SIRT1 genes among the groups after the birth of the offspring. These differences were significant between the pre-pregnancy exercise group, the pre- and during-pregnancy exercise group, and the control group (P < 0.05). It appears that maternal exercise before and during pregnancy induces changes in the mitochondrial genotype of the offspring, with a more pronounced effect on the expression of mitochondrial genes such as PGC1α and SIRT1 when exercise occurs both before and during pregnancy compared to exercise before pregnancy alone.
 

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Anaerobic capacity of the upper body is one of the special needs of wrestling athletes, which is measured in laboratory conditions by the Wingate hand test, but specialized field tests to measure this index are limited. Accordingly, in this research, an attempt was made to design a special field test to It should be used to measure the anaerobic power of the upper body of wrestlers. In this research, 20 wrestlers with an average age of 17.80 ± 2.50 years, height 172.90 ± 7.04 cm, weight 66.09 ± 13.03 kg, and body mass index 22.20 ± 2.76 kg/m2 Kurdistan province team members with national and international championship history and those without championship history were present. The movement in the hanging position was used at maximum speed.After performing the Wingate test and the designed test, the maximum, average and minimum anaerobic power and the fatigue index were calculated by the respective formulas, also the heart rate was measured immediately and the lactate level 2 minutes after the execution of the tests. Therefore, the designed test was based on the test Wingate upper body has acceptable validity, reliability and objectivity and is recommended as a valid and special test to measure the anaerobic power of the upper body of wrestlers

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Introduction and Purpose: Due to the importance of functional balance tests assessment with emphasis on
parameters influencing the balance including somatotype, this study undertaken to determine the reliability of
functional balance tests (static, semi-dynamic and dynamic) in endomorphe healthy women within 24-34 years
old. Methodology: 25 female endomorphe with the average and standard deviation age of 27.32±2.13 yrs,
height of 161.13±6.37 cm and weight of 58.28±8.46 kg, participated in this study. Functional balance tests
were assessed while Heath-Carter approach applied to determine the participant somatotype. All the functional
balance tests are used for each individual three times within 72 hours. Data distribution normalization are
evaluated by means of Kolmogorov-Smirnov test, while ICC was used for assessing the reliability at a
significance level of P<0.05. Results:The reliability of all static, semi-dynamic and dynamic balance tests used
in this study was confirmed with an endomorphe type body. Assessing static balance, the Stork and Angel
tests; semi-dynamic balance, Star Excursion Balance Test test; and dynamic balance, the Timed to Get Up
and Go and Tandem Walking tests got very good reliability level (ICC>0.80

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High-intensity interval training (HIT) induces skeletal muscle metabolic and performance adaptations that
resemble traditional endurance training despite a low total exercise volume. On the other hand, fatty acid
oxidation is increases in skeletal muscle with endurance training. This process is regulated in several sites,
including the transport of fatty acids across the plasma membrane. The transportation across this membrane is
recognized to be primarily protein mediated. Therefore, the purpose of this study was to determine the effect of
low-volume high intensity interval training on protein content of sarcolemmal fatty acids transporters (FAT/CD36
and FABPpm) in young men. Twenty recreationally active young men were assigned to a HIT (n=10, 19.3 yr old,
67.2 kg body wt, and 172.7 cm ht) or Control (n=10, 19.7 yr old, 65.9 kg body wt, and 174.4 cm ht) group. HIT
group performed three training sessions per week over 4 weeks. Each session consisted of 8-11×60 s intervals
at ∼100% of peak power output elicited during a ramp VO2peak test separated by 75 s of recovery. Skeletal
muscle (vastus lateralis) biopsy samples were obtained before and after training. HIT increased (17.5%)VO2peak (p<0.05). Also, after 4 weeks low-volume HIT, sarcolemmal content of CD36 and FABPpm increased
14 and 25 percent ,respectively (p<0.05). Therefore, the results showed that the practical model of low-volume
HIT could increase aerobic capacity and sarcolemmal content of CD36 and FABPpm. The increase indicates
that the facilitation of in muscle fatty acid transportation can be adapted which in turn increases the fat oxidation
capacity.

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Take-off is the critical phase of the long jump event. The aim of this study was to explore the relationships
between different variables and success in take-off. 37 trials performed by 8 long jumper, participants in
fourth indoor Asian senior athletics championships held in Tehran, with personal best average of 7.68±0.28
meter were recorded at 300 Hz. Five speed-related, five technical and four strength-related variables as well
as an anthropometric variable were measured using motion analysis software. More gain in vertical velocity
and less loss of horizontal velocity are considered as two criteria of take-off success and their relationships
with other variables were determined through correlation and regression analysis. Significant level of 0.05
was set. Some variables of all four groups were significantly correlated with success criteria. These variables
along with some others were entered in regression equations. The results emphasized on dominant role of
the technique and approach velocity and represented the effect of anthropometric characteristics on success
in takeoff. Furthermore eccentric strength of knee extensors was shown as the main strength factor in this
performance.

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The purpose of this study was to compare the effect of plyometric training pre and post maturation period with soccer training on electromyographical index and soccer players performance. 30 students of soccer player's pre maturation period (weight 32.38±6.59 kg, age 10.35±0.59 years, and height 141±0.06cm) and post maturation period (weight 43.79±10.96 kg, age 15.43±0.72 years, and height 156.84±0.09 cm) were selected. Subjects in the experimental group were 15 students before and after maturity period. To evaluate the age of the indices such as height, age, dental and bone age (radiographic method) was used. Then, for homogeneous groups of index of biological age radiography was used by radiologists. Before and after 4 weeks of training,, functional tests of two 20 meter speed, agility, vertical jump and also Amplitude  for vastus lateralis muscle Were taken. The result by using  Paired t-test showed that in pre maturation group in the vertical jump, agility and 20 meters there was a significant difference (P=0.002,P=0.006,P=0.001) and the other variables there was no significant difference. In variations between the groups, independent t-test showed that only significant differences was found in the test 20 meter speed (P = 0.007) and in the other variables not significantly different. The results showed that plyometric training in the Pre maturation group compared to post maturation group were more effect and these results can help in the design training for premature age groups

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Knowledge of the relationship between performance and range of motion, helping to design training programs, comply of individual with the needs of children is, therefore, The aim of research the relationship between some of the lower extremity range of motion and biomechanical parameters of the boys was performed. Hundred students in this study were randomly selected. After measuring the range of motion of lower extremity, test speed, power, balance and agility of the subjects were recorded. By descriptive statistics to determine the mean and standard deviation of the method of multiple correlations to assess the relationship between the selected range of motion and biomechanical parameters of subjects were used. Hip flexion by speed, hip abduction and knee flexion by balance and hip flexion, hyper adduction and ankle dorsi flexion significant positive correlation by the agility, the rate of hip and knee flexion by power a significant negative correlation and with other lower extremity range motion parameters showed a significant positive association. According to the research findings, seem to be characteristics of the children lower extremity range of motion and identify performance indicators for various athletic field, can be used.

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The purpose of this study was to investigate the effect of different hip joint postures on electromyographic activity of selected lower limb muscles during squat's movement. Electromyographic activity of selected lower limb muscles of 15 healthy male students was recorded while performing a squat with neutral, 15°, 30°, 45° external and internal rotation of the hip. Friedman's nonparametric test was used to compare muscle activation at different angles of the hip rotation and the Wilcoxon test was used to determine within-group differences. The results of this study showed no significant difference in the activity of Vastus medialis (p = 0.052), Vastus lateralis (p = 0.102) and tensor fasciae lata (p = 0.193) in squat between different hip joint angles, but Significant differences were observed in gluteus medius muscle activation (p = 0.001) and biceps femoris (p = 0.015) in squat between different hip joint angles. Also, the results of this study showed that gluteus medius to tensor fascia lata activation ratio was significant in squat between different hip joint angles. squat with the external hip angles can be considered as an effective method to increase gluteus medius activation and gluteus medius to the tensor fasciae latae activation ratio. On the other hand, 45 ° external and 30 ° internal hip angles can be considered as an effective method to increase the biceps femoris activation.

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