Research in Sport Medicine and Technology

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Introduction: Balance and proprioception have been introduced as two of the most important internal factors related to the occurrence of injuries in the lower limbs. The purpose of this research is to investigate the changes in static and dynamic balance and proprioceptive accuracy of knee and ankle joints of young taekwondo athletes before and after applying the fatigue protocol.
Methodology: The current research is semi-experimental. The subjects of the research were 20 teenage male taekwondo players from the statistical population. Static and dynamic balance variables were measured respectively by Stork's static balance test and Y dynamic balance test, as well as the proprioception of the ankle and knee joints at 10 degrees of ankle dorsiflexion and 30 degrees of knee flexion, by the photographic method. Then the functional fatigue protocol was applied. After finishing the fatigue protocol, all the variables that were measured before applying the fatigue protocol were evaluated again. In order to examine the intra-group changes of the research variables in the pre- and post-test stages, the paired t-test was used.
Results: The results of the paired t-test showed that after applying the fatigue protocol, there is a significant difference between the average of all the investigated variables in the post-test stage compared to the pre-test.
Conclusion: The results of the present research showed that fatigue can reduce the static and dynamic balance as well as the proprioceptive accuracy of teenage taekwondo athletes. Therefore, it is recommended to all coaches and athletes of this sport, in order to delay the appearance of fatigue and the possibility of injury, to perform specialized training exercises in the field of taekwondo and according to the age of teenagers.
 

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Background: Despite the relation between nervous system function, fatigue, and co-contraction, it seems that the difference in co-contraction changes due to fatigue induced by sprinting and endurance running probably indicates the dominance of one source of fatigue (central/peripheral) over the other. This study aimed to compare the effect of fatigue induced by endurance running and sprinting on the knee muscle co-contraction in active young women with the approach of identifying the origin of fatigue.
Methodology: Thirteen active young women volunteers (20-30 years, BMI 20-25kg/m2) were randomly selected. Subjects performed fatigue protocols during two sessions with four days of rest in between. The electrical activity of the vastus-medialis and vastus-lateralis muscles was recorded using an electromyography device before and after two stages of running 400-meter (with 100% effort) and 3000-meter (with 50% effort) during the execution of knee extension movement and co-contraction was calculated with the formula. Two-way repeated measure was used to analyze the data.
Results: There was no significant difference between the co-contraction of the selected muscles before and after sprinting (p=0.3) and endurance running (p=0.19) and no significant difference (p=0.85) between the difference in co-contraction rate in the pre-test and post-test of sprinting and endurance running.
Conclusion: Since there was no difference between the effect of fatigue caused by sprinting and endurance running on the co-contraction of the selected muscles, likely, the involvement of central factors in the appearance of fatigue caused by 400-meter sprinting and 3000-meter endurance running is similar and insignificant. The emergence of fatigue after the implementation of both protocols may be more due to environmental factors.

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Background: It seems that aerobic exercise in water is more effective in promoting motor fitness factors due to its greater resistance force compared to the dry environment. Accordingly, the aim of this study was to compare the effect of aerobic exercise in water and land on the physical fitness of inactive girls.
Methodology: Thirty non-athletic girls (18-25 years old) were randomly divided into two groups of 15 people: water and drought. The subjects performed aerobic activity for six weeks, 3 sessions per week, and 45 to 60 minutes per session with 60 to 70% of maximum heart rate. Before and after aerobic activity, their explosive power using the vertical jump (Sargent), agility by 4×9 test, reaction by reaction time test, and the balance by static balance test was calculated. For compare pre- and post-test, and to compare post-test results in water and land, One-way ANOVA with p<0.05 was used. Statistical testing was performed by SPSS version 20, and the graph were drawn by Excel 2013.
Results: After six weeks of aerobic activity (in water and land) compared to before the activity, significant improvement was found in the values ​​of explosive power (p=0.001), agility (p=0.001) and static balance (p=0.003), while the comparison of training groups in water and land did not show a significant difference (p>0.05).
Conclusion: It seems that performing six weeks of aerobic activity in water and land can affect Explosive power, agility and static balance, but no effect on reaction, also there is no difference between the two environments.

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Introduction: The purpose of the present study is to introduce and examine several genes that are related to people's sports performance and can be effective in their selection and selection in their favorite sports field. Various factors of physical fitness and training ability have been investigated along with the risk of sports injury and mental fitness of athletes.

Findings: The sports performance of people and the monitoring of sports exercises have been influenced by the vast genetic map and environmental interventions. In the present study, the performance of the aerobic system with the ACE gene and its different alleles, the strength and power performance of people with the ACTN3 gene, and the risk of injury of people with different genes such as COL1A1, COL5A1, Tenascin (TNC), apolipoprotein E and blood groups were investigated. It is a prediction; also, the trainability and mental preparation of people in the talent search process can be predicted and possibly measured by genetic knowledge. On the other hand, using the knowledge of genetics and genetic profiles of athletes can be useful for detecting genetic and cellular doping and help organizations that work in the prevention of doping, such as WADA.

Conclusion: The combination of genetic knowledge and environmental interventions play an effective role not only in discussing an athlete's talent, but also in monitoring and improving their performance. While genetics can play a significant role, the prediction of sports success based on genetic knowledge has been limited to a specific set of genes. However, developing this knowledge and identifying more genes that can aid in talent identification and exercise monitoring requires further research.

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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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^{Background: GDNF protein is involved in neurocognitive plasticity and sarcopenia, and the increase of GDNF due to resistance training leads to healthier aging and delays sarcopenia, and TRX resistance training improves the performance and morale of the elderly. The purpose of this research is the effect of six weeks of TRX training on the level of GDNF protein in the serum of elderly women.
Materials and methods: The purpose of the research is applied with a semi-experimental method including pre-test - post-test with control group and field and laboratory data. 28 elderly women aged 55 to 75 years old from the retirement center of Shahid Rajaee Tarbiat University of Tehran were randomly assigned to two experimental groups (15 people) with an average age of 60.86 ± 5.60, weight 75.00 ± 11.95, BMI ± 4.22 27.65 and six weeks of TRX training and the control group (13 people) with an average age of 64.38 ± 4.03, weight 72.69 ± 4.95, BMI 28.33 ± 2.18 and no training were divided. In the first and sixth weeks, both groups were tested for upper body strength, lower body strength and GDNF protein level by ELISA method.Shapiro-Wilk test was used to check the normality of data distribution, Levine's test for homogeneity of variances and one-way analysis of covariance test at a significance level of P < 0.05 was used to test hypotheses and statistical calculations were performed with spss24.
Results: In the results of covariance analysis of upper body and lower body strength, there is a significant difference between the two groups at the level of P <0.05. By removing the effect of the pre-test variable, there is a significant difference between the amount of GDNF protein in the experimental and control groups. By comparing the adjusted averages in the experimental and control groups, the amount of GDNF protein in the experimental group (443.102 ± 15.751) is significantly higher than the control group (209.756 ± 17.029) (P < 0.05).
Conclusion: Six weeks of TRX training had a significant effect on the amount of GDNF protein, upper and lower body strength of elderly women, and it can probably be effective in reducing or delaying sarcopenia.}
 

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Introduction
previous research has shown that ACTN3 rs1815739 and COL5A1 rs12722 polymorphisms may affect power performance. This research aimed to investigate the relationship between ACTN3 and COL5A1 polymorphisms with the baseline level of power performance and its effect on adaptation to plyometric training.
Methods
The research subjects were 38 boys with an average age of 10.3 ± 0.53. Vertical jump (CMJ) and horizontal jump (SBJ) tests were used to evaluate lower body muscle power. The plyometric training protocol was for 6 weeks. DNA was extracted from saliva and genotype was determined by PCR-RFLP method. Based on genetic analysis, people were divided into the following groups in the ACTN3 polymorphism: RX (n=20), RR (n=13), and XX (n=5), and in the COL5A1 polymorphism: CT (n=19), CC (n =8) and TT (n=11). ANCOVA test was used for statistical analysis.
Results
The results showed that plyometric training caused a significant increase in CMJ and SBJ tests (p<0.05). However, no significant difference was observed when the average basic performance and adaptation to plyometric training were compared according to ACTN3 and COL5A1 genotypes (p>0.05).
Conclusion
plyometric training effectively increases power in children, but these differences are probably not affected by ACTN3 and COL5A1 genotypes.

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Background and Aims: The current study aims to investigate the immediate effect of a researcher-made wedge treadmill on the activity of the selected lower limb muscles of flat feet individuals, so by activating the muscles, it can be used to help in the area of corrective exercise and correction of flat feet, rehabilitation and injury prevention.
Methods: The current study was a semi-experimental intervention based on the creation and introduction of a new tool and its effect evaluation. 16 subjects over 18 years old with flat feet deformity were included in this study. The subjects performed the protocol of walking at a normal speed on the researcher-made wedge treadmill at each of the lateral angles of 0, 5 and 15 degrees for 90 seconds. The electromyographic activity of five selected muscles was recorded at those angles. Statistical analysis was performed on Matlab and SPSS software. Friedman's test was used to evaluate the significant differences between angles and Bonferroni's post hoc test was used to compare two-by-two means.
Results: According to the results, the average activity of selected muscles (peroneus longus, tibialis anterior, gastrocnemius, soleus and hallucis longus) during walking between angles of 5 and 15 degrees on a wedge treadmill had a statistically significant difference compared to 0 degrees (P≤0.05).
Conclusion: This study showed that the amount of muscle activity of the lower limbs of subjects with flat feet during walking at 5 and 15-degree lateral angles has a significant difference compared to the same people walking at a zero-degree angle. Our results suggest that using the researcher-made wedge treadmill can significantly increase lower limb muscle activity in people with flat feet.

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The purpose of this study was to evaluate the effect of quadriceps muscle fatigue on electromyographic activity of selected lower limb muscles during lifting loads using different techniques. Surface electromyography activity of the rectus femoris, vastus latralis, vastus medialis, biceps femoris, semitendinous, gastrocnemius medialis and tibialis anterior muscles of 20 able-bodied women were recorded before and after the quadriceps muscle fatigue using leg-press movement, squat, stoop and strudel techniques with 20% of body weight. Analysis of Variance with repeated measures was used for data analyses (p<0.05). After fatigue when lifting the load, the activity of the rectus femoris, vastus medialis, biceps femoris and gastrocnemius medialis in squat and stoop techniques was significantly different compared to before fatigue condition. But no significant difference was observed between the activity of any of the muscles before and after fatigue in the straddle method. According to the results, it seems that when quadriceps muscle fatigue, the use of straddle technique to lift the load is more appropriate.

 

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Understanding the correct biomechanics of the knee joint during single-leg landing and correcting Incorrect movement patterns can be one of the ways to prevent the recurrence of anterior cruciate ligament injury. Therefore, the purpose of this study is to review the researches that investigated the biomechanics of the coronal plane of the lower limb during multidirectional single leg landing. The relevant articles from valid databases with the keywords Single Leg Landing, Landing, Kinematic, Biomechanics, Return to Sport, Performance Test, Functional Test, Hop Test, Kinetic thematic search methods from 1995 to 2023 were examined. A total of 1022 articles were identified then duplicate studies were eliminated in the next stage, the titles and abstracts of the studies were reviewed and 439 studies were excluded due to inconsistency with the research question. Finally, only 19 articles that met the inclusion criteria were examined. This review showed that only SLL in the forward direction has been investigated in most of the literature using a 3D motion analysis system. There is also no evidence on the biomechanics of other directions of SLL and on the use of 2D motion analysis to evaluate the biomechanics of multidirectional SLL. 

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Different postural stability and functional movements may play an important role in secondary injuries in people with flexible flatfeet compared to people with normal feet. However, the difference between static and dynamic stability and functional movements of people with and without flexible flatfeet has not been investigated. This study compared static and dynamic stability and functional movements of subjects with and without flexible flatfeet and examined the relationship between functional movements and static and dynamic stability. 96 subjects (flexible flatfeet group: 25; normal feet group: 71) functional movement screening test (FMS); Sharpened Romberg balance test and Y balance test were performed. The scores of functional movements and static stability in the normal feet group were significantly higher than the flexible flatfeet group (p≤0.05). The total score of the Y test was not significantly different between the two groups (p≥0.05). In the group of normal feet, a significant correlation was observed between functional movement scores and dynamic stability (p≤0.05). These results show that subjects with flexible flatfeet have different movement performance and static stability compared to subjects with normal feet, but they have similar dynamic stability. It may indicate that there is no connection between static and dynamic stability and these two functions are separate from each other.
 

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The purpose of this research was to design and implement a system for the surveillance of sports injuries in students. Sports injuries of male and female high school students in Ilam province were recorded by physical education teachers using online methods and paper forms during one academic semester. At the end, a questionnaire was used to survey them regarding these methods. The research is of a descriptive-comparative type and Chi-square (x²) was used at the significance level (P<0.05) to analyze the results. A total of 151 injuries were reported, of which 76 injuries (50.4 percent) were registered with the online method, 70 injuries (46.3 percent) with the online paper method, and 5 injuries (3.3 percent) with the paper method. Online registration (146 injuries) is significantly more used than paper registration (75 injuries) (p=0.001) physical education teachers give the reasons for using the online method more: availability, easier working with it, and recovery It is easier to record information. On the other hand, they mentioned the interruption and slowness of the internet speed as things that can cause disruption. According to the results, it seems that the use of online methods is more effective in registering sports injuries in schools.

 

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The main goal of this research was to design and evaluate the features of a "home-based weightless fitness device with digital adjustment" for performing muscular exercises in a home environment. To achieve this goal, a combined quantitative and qualitative approach was employed, and a detailed assessment of the device's performance was conducted. In the initial stage, existing fitness equipment, resistance training methods, and technological advancements were investigated. This review provided fundamental information for the initial design of the device. Subsequently, using design software such as Rhino Cross 6 and AutoCAD 2018, precise three-dimensional models and initial prototypes were created. To validate the device's resistance, a digital force gauge was utilized, measuring the displayed force in eight different settings with the resistance adjusted on the device, allowing for the calculation of device deviation from standard and error margin. Furthermore, to assess the device's reliability three seated movements—leg press extension, seated chest press, and seated front raise bicep curl—, each performed with eight consecutive repetitions using a 10-kilogram weight. The results of Pearson's correlation coefficient (0.9) showed that the instrument has high reliability. Also, the results of intra-correlation reliability coefficient (0.8) showed that the device has good reliability and high accuracy in the produced resistance in different movements and repetitions. Ultimately, this research introduces an effective tool for muscular exercises in a home setting. With its precise resistance adjustment capability and versatility in exercise options, the device empowers athletes to perform exercises with greater precision. Overall, this study yields practical and implementable results, potentially playing a crucial role in enhancing the health and fitness of athletes and the general community.
 
 

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The purpose of this study was determining validity and reliability of the Athlete Fear Avoidance Questionnaire (AFAQ). For this purpose, 120 atheltes with different levels of skills in different fields, were chosen and completed the the AFAQ, the Kinesiophobia Questionnaire, and the Pain Catastrophizing Scale and the Sport Injury Appraisal Scale. AFAQ was confirmed by using translation-back translation method and face validity and translation accuracy. Cronbach's alpha index, exploratory and confirmatory factor analysis, Pearson correlation coefficient and intraclass correlation coefficient were used to check construct validity, internal consistency and temporal reliability. The results showed that the one-factor model of the athletes' fear-avoidance questionnaire had a poor fit, for this reason, after conducting the exploratory factor analysis and identifying three factors in these questionnaires, the confirmatory factor analysis model also fitted the data well with this the three-factor model. So that the CFI index was 0. 96 and the TLI index was 0. 94 as well as the RMSE index of 0. 05 and the chi-square ratio to the degree of freedom(X²/DF) was 1. 39. The internal consistency of the questionnaire was also confirmed. Based on this, the Persian version of the AFAQ has 3 factors and includes 10 questions and three catastrophic constructs (items 1, 5, 8), fear of movement (4, 6, 7) and fear-avoidance beliefs (items 2, 3, 9, 10) was confirmed in the community of Iranian athletes.
 

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Aim and Background: Ankle is one of the most common sports injuries caused by direct collisions with opposing players or the ground, tackles from inside and outside, jumping and landing. Among these injuries, external ankle sprain is one of the most common injuries that is associated with ankle instability. The purpose of this research is to compare balance exercises and hopping on the proprioception of athletes with functional ankle instability.
Materials and methods: 30 athletes with functional instability of the ankle were randomly divided into 2 study groups of the clinical trial. The first group included athletes with functional ankle instability doing hopping exercises (15 people), the second group included athletes with functional ankle instability doing balance exercises (15 people). At first, the proprioception of their ankle joint was evaluated with the help of photography, and then they did exercises for 6 weeks, and at the end, the proprioception of the ankle joint was evaluated again. SPSS version 20 software was used to analyze the data of this research.
Results: The results showed that balance and hopping exercises significantly reduced the absolute error of ankle dorsiflexion and plantarflexion reconstruction (p<0.05). Also, there is a significant difference between the two groups of balance exercises and hopping (p<0.05).
Conclusion: The results of the present study showed that balance and hopping exercises improved the proprioception of the ankle joint in athletes with functional instability of the ankle, and hopping exercises are more effective than balance exercises.
 

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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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 Rectal prolapse is a complication arising from internal sphincter dysfunction causing significant challenges. A primary factor in its development is pelvic floor muscle weakness. Accordingly, the present study aimed to compare the effects of core stabilization functional, EMS, and combined exercises on muscle strength and endurance of the pelvic floor in patients with rectal prolapse. In this semi-experimental study, with a design pre and post-test and a control group, 48 women with rectal prolapse in Isfahan with an average age=45.2 years and a BMI=26.2 kg/m2, were selected and divided into 4 groups(n= 12); Functional training, EMS training, Combined training and Control randomly. Functional training protocol consisted of 9 movements, 3 sessions per week and each session lasted for 30 minutes in the first week and gradually increased to 90 minutes in the 8 week. Also, EMS trainings were carried out for 8 weeks, 3 sessions per week for 40 minutes, using EMS and Biofeedback devices. Furthermore, the combined training protocol was implemented for 8 weeks and 3 sessions per week (in each session, at first EMS training and then functional training) for 40 minutes according to the overload principle. Strength and endurance of pelvic floor muscles were measured before and after the exercise program. In order to analyze the data, multivariate covariance and post hoc Bonferroni tests were used using SPSS 26 software at a significant level (P≥0.05). The results of the study showed a significant increase in the strength and endurance of the pelvic floor muscles in EMS and combined exercise groups (P≥0.05). However, in the functional exercises group, although an increase in the strength of the pelvic floor muscles was observed, this increase was not significant (p≥0.05). Also, the changes caused by the combined group on the variables were significantly more than the groups of functional and EMS exercises alone (P≥0.05). These results show the effect of electrical stimulation along with functional training on increasing the endurance and strength of the pelvic floor muscles, which, as a result, improves rectal prolapse. Therefore, it is suggested that sports therapy centers, doctors, and therapists use these methods, especially combined exercises, to improve rectal prolapse.