Sport Sciences and Health Research

Introduction: The present research aimed to compare and follow-up the effect of 8-week corrective exercises with and without the myofascial release on functional kyphosis deformity in young adults. Methods: It was a randomized controlled trial in the university laboratory. Forty-five male students suffering from abnormal hyperkyphosis deformity (kyphosis of more than 42°) were selected and randomly assigned to three groups: corrective exercises, combinational exercises (corrective and myofascial release), and control. The Mean±SD age, height, and weight of the study sample were 22.12±2.88 years, 175.44±6.80 cm, and 71.21±7.31 kg, respectively. The study groups did the exercises for 8 weeks, under the direct observation of the researchers. The kyphosis angle of the participants was measured using a flexible ruler, at the baseline, post-test, and follow-up (4 weeks after the end of the exercises) stages. The collected data were analyzed with repeated measures Analysis of Variance (ANOVA) and Analysis of Covariance (ANCOVA) tests. Results: After 8 weeks of exercises, the degree of kyphosis in the post-test and follow-up stages was significantly lower than that in the pre-test, in both training groups. The results of the ANCOVA test demonstrated that the thoracic kyphosis degree in the combinational exercises group was significantly lower than that of the corrective exercises group (P≤0.05), in the post-test and follow-up stages. Conclusion: According to the results, the corrective exercises program in combination with the myofascial release is more effective than the corrective exercises alone, in correcting the thoracic kyphosis deformity.

Introduction: Since people experience fatigue after anterior cruciate ligament injury during exercises, it is important to understand how fatigue affects the biomechanical movement patterns. Therefore, this study aimed to investigate the effect of fatigue on ground reaction force variables during single-leg landing in athletes with a history of an anterior cruciate ligament sprain. Methods: it was a case-control study conducted in the University Laboratory. The sample consisted of 36 male athletes who were divided into three groups: 12 people with Anterior Cruciate Ligament Reconstruction (ACLR), 12 people with Anterior Cruciate Ligament Deficiency (ACLD), and 12 people as the control group. Fatigue was induced via the repetitive sets of double-leg squats (n=8), which were interspersed with the sets of countermovement jumps (n=2) and single-leg landings (n=3) until squats were no longer possible. A 2×2 repeated-measures multivariate analysis of variance was used to detect the main effects of group (ACLD, ACLR, control) and fatigue state (prefatigue, postfatigue) on the ground reaction forces variables. Results: The results showed a significant decrease in the peak vertical force and internal-external ground reaction force in the ACLD group after fatigue. Regardless of the fatigue state, the peak vertical ground reaction force in ACLD and ACLR groups was significantly lower than that in the control group. Conclusion: The athletes with the ACL injury, regardless of the selective treatment type, use compensatory strategies to reduce the contact forces on the lower extremity, compared with healthy athletes.

Introduction: Wrestling is one of the most popular Olympic sports in Iran. Therefore, preseason screening and the prevention of sports injuries are very important. This study aimed to investigate the relationship between the history of injury and Functional Movement Screen (FMS) scores of the national team wrestlers and determine the cut-off point. Methods: The statistical sample included 136 national team wrestlers. The obtained data were analyzed using the Pearson correlation coefficient, t-test, ROC curve, and contingency table. Results: The results showed that FMS scores were higher in the wrestlers without previous injury compared to the injured ones. The t-test results demonstrated no significant difference between deep squat, straight and active leg raise, trunk stability push-up, and rotatory stability. According to the results, there is a poor negative, but statistically significant, the relationship between the number of previous injuries and FMS scores. Based on the ROC curve for FMS, the cut-off point of 16.5 was reported with the sensitivity and specificity values of 0.587 and 0.658, respectively. Conclusion: The results indicated that FMS can be used for fast and accurate control of injury probability in wrestling athletes. Therefore, besides the medical tests, FMS tests should be employed by wrestling coaches as a valid tool for injury prevention and the identification of athletes prone to injury.

Introduction: This study aimed to investigate the effect of a 4-week core stability training program on landing kinetic parameters in athletes with functional ankle instability during a single-leg drop landing exercise. Methods: This study used a pre-post quasi-experimental design and was conducted in the biomechanics laboratory. A total number of 24 athletes with functional ankle instability participated in two experimental (n=12) and control (n=12) groups. The experimental group performed core stability training for 4 weeks. The kinetic variables (maximum vertical Ground-Reaction Force [GRF], maximum shear GRF, and time to peak vertical GRF) were measured with force plate at the frequency of 400 Hz, in the pre-test and post-test. The obtained data were compared using Analysis of Covariance (ANCOVA) and multivariate analysis of covariance MANCOVA in SPSS V. 18. Results: In the experimental group, all variables significantly differ between the pre-test and post-test. Also, the ANCOVA and MANCOVA indicated significant differences between the experimental and control groups in all variables. Conclusion: The results indicated that the core stability training improved the kinetic parameters of landing in people with functional ankle instability; thus, it can reduce the re-injury risk of the ankle.

Introduction: Musculoskeletal Disorders (MDs) largely contribute to occupational diseases in the workplace. Prevention from these disorders requires their evaluation in different occupations. This study aimed to compare the MDs of the neck between the teachers of Physical Education (PE) and those of the other majors in the high schools of Tehran City, Iran. Methods: The study sample included 180 teachers of mathematics, PE, and the religion and lifestyle in the high schools of Tehran (with the Mean±SD age of 42.11±6.65 years, and the Mean±SD weight of 72.28±12.98 kg). The participants were selected from 19 districts of the Tehran Departments of Education using multistage cluster sampling. The standard Nordic questionnaire was administered to investigate MDs among the teachers. The obtained data were analyzed with the Chi-square test to compare the MDs of the neck between the three groups of teachers. Results: A significant relationship was observed between the neck problems of the female (P=0.016) and male (P=0.017) PE teachers and the other teachers. Moreover, the neck problems were associated with the teaching experience (P=0.024) and teaching major (P=0.004). Conclusion: Based on the results, it seems that regular exercise can reduce the developing risk of MDs in the neck. Thus, this study recommends the performance of regular exercise and the correction of job-related postures to all teachers.

Introduction: Nowadays, the use of artificial turf fields has become widespread. Given the high prevalence of noncontact injuries among female soccer players and high contribution of the Anterior Cruciate Ligament (ACL) injury, this research was conducted to compare biomechanical risk factors in the incidence of ACL injury for elite female soccer players during shearing maneuver and header on the natural grass and artificial turf fields. Methods: Sixteen players were selected from U-14 women’s national team by the convenience sampling method and started to perform the skills. Knee joint information was calculated by a 3D imaging system and a force plate. Statistical differences were reported using the dependent t-test at a significant level of 0.05. Results: The findings showed that the biomechanical behavior of the lower extremity while performing soccer skills on the natural grass was affected differently from that on the artificial turf. Results also demonstrated that the torque applied to the knee joint on the natural grass was higher than that on the artificial turf (P=0.039). Angular velocity on the artificial turf was also higher than that on the natural grass (P=0.006). Conclusion: The higher knee joint torque and the lower angular velocity on natural grass may result in a higher risk of ACL injury on the natural grass than on the artificial turf. Therefore, the use of prevention programs for ACL injury is crucial to minimize the incidence of lower extremity injuries.

Introduction: Training at altitude or in a hypoxic environment has gained attention among athletes, coaches, and scientists to enhance sea-level performance. However, the efficacy of “Living-Low, Training-High, Training-Low” (LLTHTL) strategy to escalate the mechanisms associated with enhancing performance in the human athletes is still unknown. The present study aimed to investigate the effect of the LLTHTL on Hypoxia-Inducible Factor-1 alpha (HIF-1α) and peroxisome Proliferator-activated Receptor-Gamma Coactivator-1alpha (PGC-1α) levels in elite endurance runners.  Methods: The study has a crossover design in University laboratory. Eight elite male runners (Mean±SD age: 24.50±3.96 years; Mean±SD height: 179.75±4.62 cm; Mean±SD body mass: 67.37±3.42 kg; Mean±SD body mass index: 20.85±1.11 kg/m²) took part in the research. After 4 weeks of Living-Low (LL), the athletes performed 4 weeks Training-High (TH) and then, 3 weeks training-low (TL). Main Outcome Measures: Anthropometric parameters, time trial (1500 m), PGC-1α, and HIF-1α levels were measured in four different time points: pre-LL, post-LL, post-TH, and post-TL.  Results: There were no significant differences between the 4 time points for body mass and body mass index (P>0.05). The time trial was improved significantly (p <0.001) at post-TH as well as post-TL compared with the pre-LL and post-LL. TH decreased HIF-1α level but did not affect PGC-1α. Besides, TL increased both HIF-1α and PGC-1α.  Conclusion: Training at altitude reduces HIF-1α and training at sea-level increased PGC-1α and HIF-1α levels. Both types of training induced an improvement in the time trial. Athletes and coaches seek advice on the effective training strategy to enhance performance at different altitudes.