نشریه مطالعات طب ورزشی
پیاپی 26 (پاییز و زمستان 1398)

Some sport activities such as skiing causes athletes to be constantly exposed to vibrations caused by rough terrain which can lead to muscle fatigue in many repetitions. The purpose of this study is to investigate the effects of musculoskeletal fatigue on vibration transmissibility coefficient and muscle activity in subjects are exposed to floor vibrations. For this purpose, 12 young men were exposed to floor vibrations in the squat mode at frequency of 12 Hz and intensity of 0.9 m/s2 to achieve complete fatigue. The results of this study show that the occurrence of the fatigue in the musculoskeletal system of the body increases the amount of both variables of the study simultaneously. In other words, increasing of the muscle activity alone does not indicate fatigue phenomenon. Because according to the results, increasing the amount of muscle activity without occurrence of the fatigue reduces the vibration transmissibility coefficient in the muscle.

Decrease in knee proprioception and muscles strength are outcomes of anterior cruciate ligament (ACL) rupture that sustained with patients post-surgery. The aim of this study was to compare the knee joint positioning sensation and muscle strength in patients with completed sport rehabilitation program and returned to exercise with their healthy matches. Twenty-five male basketball players (11 participants with autograft reconstruction hamstring or surgery and 14 healthy participants) participated in this study. Flexor and extensor peak torque of the knee at the angular velocities of 60 and 180 deg.s-1 and proprioception at 45̊ were evaluated in both dominant and nondominant legs by isokinetic dynamometry. Data were analyzed by F test and independent samples t-test. The results of this study showed that there is no differences in flexion and extension peak torque at 60 deg.s-1 angular velocity (p=0.483), peak extension moment at 180 deg.s-1 in dominant and nondominant (p=0.371, p=0.890) and joint positioning sensation between dominant and nondominant legs (p=0.896) in groups. However, extension peak torque in the injured group was lower than healthy group in both dominant (p=0.034) and nondominant legs (p=0.043). According to the results of this study, it can be concluded that after successive completion of rehabilitation program, surgery-induced outcomes could be improved, and it can reduce re-injury risk in athletes.

The purpose of this study was to investigate the epidemiology of sports injuries and falling in Iranian students at school and during physical education and physical activity at schools. In this study, 6,300 males and female 12-16 year-old junior secondary students from Tehran, Karaj, Yazd, Khorramabad, Sari, Shahrekord, Bandar Abbas, Mashhad and Tabriz participated in the study. Their injuries were recorded in a prospective manner. For data analysis, descriptive statistics and cross-tabulation were used to compare the variables according to gender. Most of the students' injuries were for male at the age of 14 (56.3) and for girls at the age of 13 (32.4%). The findings showed that 457 (10.42%) of the students were injured that highest number of injuries occurred to female students (62.4%) outside the physical education course (35.4) and during the absence of the physical education teacher (67%), but in male students, 45.4% injuries occurred in physical education course during presence of a physical education teacher (61.6%). Girls in highpopulation classes were at higher risk of injury (49 percent), while boys were more likely to be injured in lower-population classes (39.6). Among the various sports, the highest rate of injury in boys was in football (69%) and futsal (11.6%), and in girls were volleyball (17.2%) and handball (4/7 %). Most injuries occurred in crowded classes. Injured students have no history of exercise and they showed more damage with less experience. Most boys' injuries occurred during exercise and for girls during non-exercise activities. It seems that by focusing on the presence of physical education teachers during sports hours and their favorite sports and increasing the activity time in the form of appropriate prevention programs during activity and non-sports, it is possible to prevent students from being harmed. Implementing a comprehensive and appropriate strategy, including appropriate sports activities for each age group, determining and controlling the potential risks of sports activities is very important to prevent injury.

The purpose of this study was to investigate the effect of training with external sensory timing on the mean area and amplitude of the center of pressure during static and dynamic balance in the elderly. Thirty-six elderly (all males) were randomly assigned to control, walking, and training with external sensory timing (experimental) groups. The training sessions were conducted during six weeks (three sessions per week). The participants were administered two postural tasks of static and dynamic balance prior and following the treatments as their pre- and post-tests. The results indicated that there were no significant differences in the center of pressure area and distance means from pre- to post-tests of all groups. However, training with external sensory timing significantly increased the amplitude of the center of pressure in the anterior-posterior and the internal-external directions of the experimental groups. The results indicated that training with external sensory timing significantly improved the dynamic balance of the elderly. Therefore, this method can be considered as a low-cost, modern, and simple method to be included in the training programs of the elderly to improve their dynamic balance.

The aim of this study was to Analysis of Selected Kinetic-Temporal Variables of Lower Extremity of Elite junior volleyball players during Block Jump Skill. 30 junior volleyball players of National Team of the Islamic Republic of Iran stand on Force platform and performed block jump skill, peak vertical forces, Time of peaks, Time elapsed between peaks, time of contact, end of the landing, total landing time, Ratio between peaks and between the time of the peaks were calculated. There are significant positive correlations between Times of peaks, Time elapsed between peaks and peak vertical forces and negative correlations exist between other variables of the research. So in volleyball players great stress would be placed on lower extremity at the moment of landing. Because of increasing time of the second peak will decrease the impact force, although it is not appropriate for volleyball goals.

Although foot orthotics with different stiffness is widely used for the treatment of lower extremity abnormalities and injuries, but their effect on foot coordination and variability is unclear. The purpose of present study was to investigate the effect of different stiffness of shoe orthosis on foot inter-joint coordination pattern and variability during the stance phase of running. Fifteen healthy active men volunteered to participate in this study. Coordination pattern and variability were calculated from kinematics raw data using a Continuous Relative Phase method while running with different stiffness insoles inserted in a sandal. A repeated measure of ANOVA test was performed to test the hypothesis (p < 0.05). a part of the results showed that running with hard, soft, and semi-hard increased about %95, %179, and %220 of continue relative phase inversion: eversion of the ankle and tarsometatarsal joint in first 25% of stance phase compared to no insole condition (p < 0.001). Generally, the findings show that insole stiffness may affect lower extremity mechanics by changing foot inter-joint coordination and variability. Thus, insole stiffness should be considered when specialists use the orthotic devices for treatment.

The purpose of this study was to investigate the Epidemiology of Sport injuries in women's Kabaddi premier league(2015).In this study132players of11teams participated.Data relating to injury was collected by using injury report form and the help of tournament doctor.x2Test was used to analyze the data.A total of30matches42injuries were recorded.The injury incidence rate was200injuries per1000hours match.The upper limb(40.5%)and head and neck(28.6%)were the most commonly injured body regions in the women.The most injured anatomical areas were head and face(28.6%)and fingers(16.7%).The most common type of injury in women was contusion, bruise and hematoma(57.1%).Contacting with opponent was the most important mechanism of injury (85.7%).Injury rate for defense players was52.4%and%64/3of the injuries occurred in the second half.Kabaddi is a complex sport that requires a range of skills and injury incidence risks are high during the games. Therefore it is advised for the medical team and coaches to consider the above data in order to prevent injuries.

The aim of the present study was to comparison the effect of 8-week taping and selected therapeutic exercises on range of motion, proprioception and pain in gymnasts with shoulder impingement syndrome.

15 patients were randomly assigned in taping group, 15 patients in therapeutic exercises group and 15 patients in control group. Patients in therapeutic exercises group received training sessions, for 8 weeks. Range of motion, proprioception and pain were measured with an Electrogoniometer, Biodex isokinetic dynamometer and visual analog scale, respectively.

The results showed significant differences between the two experimental groups than control group for all outcome measures after the intervention. Therapeutic exercises group showed significantly larger improvement in range of motion than taping group.

According to research findings, therapeutic exercises cloud be more effective than taping in gymnasts with shoulder impingement syndrome.

This study proposed to compare the isokinetic performance profile of knee and ankle joint muscles in professional and amateur speed skaters. Sixteen speed skaters divided into two groups of amateurs and professionals were included in this survey. Isokinetic parameters of ankle and knee joints evaluated by using the Biodex isokinetic-dynamometer. Shapiro-Wilk and independent t-test were applied for statistical analysis at the significant level of ≤0.05. Independent sample t-test results showed a significant difference in isokinetic parameters such as the power of knee extensor muscle, power and deceleration time in inversion and eversion between amateur and professionals. It seems that the significant difference between professional and amateur speed skaters in isokinetic parameters is related to neuromuscular ability (power and deceleration time of invertor and evertor muscles groups). It is suggested that these parameters be considered in the training of this group of athletes.

This study aimed to investigate the comparison of prevalence of trunk dysfunction among athletes in three different sports. Thirty athletes were assessed in a purposely available manner, from each sport by Tuck jump test, and individuals with trunk dysfunction were compared with each other. Analysis of variance ANOVA and Chi-square tests were used to analyze the data. The results showed that there was no significant difference between Tuck jump test scores and trunk dysfunction among three different sports, but valuable information such as the percentage and number of people with trunk dysfunction in table tennis, cycling and swimming (breaststroke and butterfly stroke swimmers), which have different natures and movement patterns, was obtained. By accurately screening, assessing and identifying the trunk dysfunction, the risk of injury, especially anterior cruciate ligament injury, which has a direct relation with trunk dysfunction, can be reduced in athletes.

The global outbreak of Coronavirus 2019 has affected the routine life. The aim of study is to review the background of studies on the clinical symptoms and consequences of Covid-19 infection in pregnant women and their offspring, as well as the role of physical activity on the maternal health. In this survey, all articles in the different databases were searched and investigated by using keywords. The most common maternal/ neonatal complications included fetal and respiratory distress, preterm delivery and mild infection in newborns. Guidelines have recommended physical activity to improve physical and mental condition. Studies have shown that regular physical activity with the moderate intensity can lead to strong immune responses in pregnant women. Due to the limited information, it is necessary to monitor pregnant women and their infants for a long time and to examine the role of physical activity to improve the physical and mental condition.

Functional movementscreen-) FMS (and Y balance- test are functional assessment tools with some specific relevance. However, information regarding a potential relationship between these assessments and Hop test is still insufficient. Additionally, the FMS and Y balance are used to predict the risk of sport injuries occurrence. Currently, no research is available on the differences in FMS, Y balance, and Hop test between groups with high and low risks of sport injuries.

One hundred and thirty-one premier league young adolescents (man/woman) volleyball players from Zanjan Province (age=15.78±1.83 years old; height= 176.30±7.07 cm; weight= 67.56±6.18 kg; BMI=21.74±1.63 kg/m2) participated in this cross sectional study. The pre-participation screening consisted of FMS, Y balance, DEVIS, and Hopping test has been recorded during the pre-season time. All participants followed the routine training in season. Volleyball players were divided based on the FMS score considering scores ˃14 as low risk criteria and ≤14 as high risk criteria of sustaining musculoskeletal injury. The correlations of composite and individual item scores of these assessments were analyzed, and the differences between groups with high and low risks of sports injury were compared.

independent t test showed the Y balance, DEVIS, and Hopping tests scores were all significantly higher in athletes who got FMS scores ˃14 comparing to those who got FMS scores ≤14.

the result showed functional movement test scores are different among volleyball players with/without high risk of sustaining musculoskeletal injuries. Athletes who get FMS scores ≤14 (whom are likely to sustain injuries) are supposed to have lower scores on other functional movement tests as well. It is therefore suggested that functional movements screening tests might be of use for recognizing those athletes with higher risks of sustaining musculoskeletal injury.