فهرست مطالب

Sports Medicine - Volume:7 Issue: 4, 2017
  • Volume:7 Issue: 4, 2017
  • تاریخ انتشار: 1395/10/22
  • تعداد عناوین: 13
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  • Seyed Esmaeel Shafiei, Sepideh Peyvandi, Mohammad Hosein Kariminasab, Masoud Shayesteh Azar, Seyed Mohammad Mehdi Daneshpoor *, Alireza Khalilian, Zeinab Aghajantabar Page 2
    Background
    Anterior cruciate ligament (ACL) rupture is the biggest concern for orthopedic surgeons who are involved in sports injuries, so most of ACL reconstruction surgeries are sports related. ACL injuries in female athletes are 2 - 8 times more common than male athletes in similar sport injuries..
    Objectives
    The aim of this study was to compare knee laxity changes in the menstrual cycle in female athletes referred to the orthopedic clinic of Imam Khomeini hospital in the north of Iran, Sari, 2013..
    Patients and
    Methods
    The present descriptive study was conducted on 40 female athletes that were referred to the orthopedic clinic. Hormone levels, such as estrogen and progesterone were assessed by one laboratory in 3 phases of the menstrual cycle. We used Lachman test and anterior drawer test for knee laxity rate. The descriptive statistics were calculated as indices of central distribution of bonds (x ± SD) and relative frequency distribution was used for qualitative variables..
    Results
    The results of the current study showed that there is no significant difference in ACL laxity in female athletes in three phases of menstrual cycle; namely menstruation time, ovulation time and mid-luteal phase..
    Conclusions
    Despite numerous studies and research in the field of knee laxity and effects of female hormones, many researchers do not agree about the effect of female hormones on knee laxity. The current study also reported no relationship between female hormones and knee laxity, while statistics show fundamental difference between male and female athletes..
    Keywords: Knee, Joint laxity, Athletes, Menstrual Cycle
  • Rafael Leonardo Ferreira Da Luz, Fernando Alves Da Silva, Marcelo Coertjens* Page 3
    Background
    The kitesurfing athletes endure unexpected conditions in terms of the function of irregularities in the surface of the water that requires a correct proprioceptive response in order to maintain equilibrium and execute the required movements while maintaining contact with the board and the water..
    Objectives
    The objective of this work was to use the star excursion balance test to compare the dynamic equilibrium of athletes who engage in kitesurfing activities with non-athletic subjects..
    Methods
    Fourteen kitesurfing athletes and fifteen sedentary male subjects completed three rounds of the star excursion balance test: familiarity, test one and test two. During each phase the eight directions of the test were performed three times on each leg and the maximum distance reached by the leg (cm) was measured before being divided by the length of the lower limb (%). To compare the intergroup averages, a student test t to independent samples was performed. To compare the averages across the eight directions in the same group, the repeated-measures ANOVA test was employed and to compare the averages of the right leg and the left leg, a student test t to dependent samples was used (α = 0.05)..
    Results
    For both groups and in both legs, the distance reached in the medial, posteromedial, posterior and posterolateral directions was similar and further than the other directions. It was observed that the athletes in the comparison intergroup achieved superior results than those in the control group in the medial, posteromedial, posterior and posterolateral directions in both right and left legs and the lateral direction in the right leg (P
    Conclusions
    Kitesurfing activities result in proportionate adaptations in the dynamic equilibrium of athletes, maybe in function of adaptations in the neuromuscular structure, resulting in a better performance in situations that cause disequilibrium..
    Keywords: Athletic Performance, Adaptation, Physiological, Postural Balance
  • Mohammad Ali Sanjari, Sahar Boozari, Ali Ashraf Jamshidi *, Mohammad Reza Nikmaram Page 4
    Background
    Flat foot, as one of the common foot deformities can affect gait biomechanics and risk of lower extremity injury. Fatigue, as a high load task, can also change biomechanical parameters of locomotion. Studying normal and flat footed individuals under high load tasks such as fatigue can elucidate their differences more easily..
    Objectives
    In this study, center of pressure (CoP) changes were studied between individuals with flat and normal feet after fatigue. CoP is one of the important gait measures which can show various biomechanical behaviors of different foot shapes..
    Methods
    Seventeen subjects with normal feet and 17 with flat feet walked across two force plates before and after a functional fatigue protocol. Standard deviation of CoP in mediolateral direction (SD of CoPx) and in anteroposterior direction (SD of CoPy), overall mean velocity of CoP and length of CoP construction line of both groups were analyzed. The values of SD of CoPy and length of CoP construction line were normalized to individual foot lengths prior to statistical analyses..
    Results
    There were no significant between-subject effects for all CoP measures. The only significant finding was the within-subject effect for the SD of CoPy (P = 0.008) with a large effect size (partial eta squared = 0.21). Fatigue resulted in lower SD of CoPy in both groups..
    Conclusions
    Lower SD of CoPy indicates less fluctuation of CoPy and a probable less center of mass movement which could reduce the risk of injury. Furthermore, the similar fatigue response in both groups of individuals with normal and flat feet indicates a similar biomechanical behavior despite their different foot arch height..
    Keywords: Flatfoot, Fatigue, Walking
  • Shalini Agarwal *, Ekta Mann Page 5
    Background
    Wrestling is a very popular sport the world over and its popularity is rapidly increasing in India. However, due to its arduous nature it is associated with a high incidence of injuries. Out of all the injuries, those to the knee are one of the commonest injuries reported..
    Objectives
    Our aim was to study the pattern of these injuries in the Indian wrestlers..
    Methods
    A prospective study was conducted involving 196 wrestlers who were followed up over a period of 2 years. Their knee injuries were studied by means of a structured questionnaire which they filled up with assistance from their athletic trainers..
    Results
    There were a total of 188 injuries in 121 wrestlers with overall injury rate of 5.13/1,000 athlete exposure. 35 wrestlers sustained 71 knee injuries (71/188; 37.77%). 71.83% injuries were new. More number of injuries occurred in competition (incidence density ratio = 20.7) and in attack position. There was a statistically significant association with age and duration of practice. No association was found between these injuries and style of wrestling, weight and height of wrestlers. Ligament sprains and muscular strains were the commonest injuries..
    Conclusions
    Goal of any such study is to minimize the risk of injury in the young athlete by understanding the factors responsible and development of preventive programs. We hope to do just that with this first study involving Indian wrestlers..
    Keywords: Injuries, Wrestling, Epidemiology
  • Cornelia Blank*, Wolfgang Schobersberger, Veronika Leichtfried, Stefan Duschek Page 6
    Background
    Doping is a highly relevant problem in sport, even in adolescent athletes. Knowledge of the psychological factors that influence doping susceptibility in young elite athletes remains sparse..
    Objectives
    This study investigated the predictive potential of different health-psychological constructs and well-being on doping susceptibility. The main hypotheses to be tested were positive associations of fear of failure, external locus of control, and ego-oriented goal orientation as well as negative associations of confidence of success, task orientation, internal locus of control, and performance motivation with doping susceptibility. Low levels of well-being are furthermore expected to be associated with doping susceptibility..
    Methods
    Within this cross-sectional study, 1,265 Austrian junior athletes aged between 14 and 19 years responded to a paper-pencil questionnaire..
    Results
    Performance motivation was a negative, while depressive mood, self-esteem, fear of failure and ego-oriented goal orientation were positive predictors of doping susceptibility. In addition, participants who were offered performance enhancing substances in the past were particularly susceptible to doping..
    Conclusions
    The study corroborates the predictive value of classical psychological constructs in doping research, initially analyzed in view of adult athletes, also for adolescents’ doping susceptibility..
    Keywords: Doping Susceptibility, Well, Being, Fear of Failure, Confidence of Success, Performance Motivation, Goal Orientation, Locus of Control
  • Vajihe Saedi Marghmaleki, Hojjatallah Alaei * Page 7
    Background
    Previous studies on the medial prefrontal cortex (mPFC) has shown that this area plays an important role in addiction behavior. Other studies also indicated that exercise decreases use of morphine..
    Objectives
    The aim of this study was to evaluate the effects of short-term exercise on trends for use of morphine with an intact mPFC and lesion of that area..
    Methods
    50 rats randomly were selected and divided into 5 groups. 1-exercise. 2- Morphine Lesion. 3- Morphine Exercise Lesion. 4- Morphine. 5- Morphine and Exercise. All groups received morphine for 9 days except exercise group. On the 10th day, the symptoms of addiction were evaluated. To determine the effects of exercise, a treadmill apparatus was used for exercising..
    Results
    Our results indicated that exercise with intact mPFC area significantly decreased the tendency of using morphine which is verified by changes in symptoms (P
    Conclusions
    It seems that a lesion of mPFC area significantly reduced the effect of short-term exercise on the usage pattern of morphine..
    Keywords: Tread Mill Running, Withdrawal Symptom, mPFC, Lesion, Morphine
  • Jalil Reisi *, Kamran Ghaedi, Hamid Rajabi, Sayyed Mohammad Marandi Page 8
    Background
    Irisin is a new myokine secreted from the skeletal muscle and appears to affect the metabolism of adipose tissue..
    Objectives
    The mechanisms of cellular and molecular identification by which exercise training exerts its benefits remain unclear and are under investigation..
    Methods
    We examined the effect of 8-week resistance exercise on plasma irisin levels and expression profiles of muscle FNDC5 and subcutaneous adipose tissue UCP1 in male rats. Sixteen adult male rats were divided into two groups, control (n = 8) and exercise training (n = 8) groups. The training group received exercise for 3 days/week on a specific ladder (120 cm height) with a carrying load of 50% of body weight, which was attached to their tails..
    Results
    The weight of the load was gradually increased during the training sessions, ultimately reaching 200% of the body weight of rats in the final week. There were three sets of five repetitions with a 3-min rest between each set of exercise sessions and 1 minute between repetitions. Plasma irisin levels and relative mRNA expression of the genes UCP1 and FNDC5 were assessed. The results demonstrated a significant increase in the irisin levels after 8 weeks of resistance exercise (P
    Conclusions
    Therefore, we can conclude from this study that resistance exercise may improve body composition possibly through increased thermogenesis in white adipose tissue through the secretion of irisin..
    Keywords: Resistance Training, Irisin Protein, UCP1, FNDC5
  • Alexandre Moreira*, Marcelo Saldanha Aoki, Chris Carling, Rafael Alan Rodrigues Lopes, Ademir Felipe Schultz De Arruda, Marcelo Lima, Umberto Cesar Correa, Paul S. Bradley Page 9
    Background
    There have been claims that small-sided games (SSG) may generate an appropriate environment to develop youth players’ technical performance associated to game-related problem solving. However, the temporal change in technical performance parameters of youth players during SSG is still unknown..
    Objectives
    The aim of this study was to examine temporal changes in technical and physical performances during a small-sided game (SSG) in elite soccer players..
    Methods
    Sixty elite youth players (age 14.8 ± 0.2 yr; stature 177 ± 5 cm; body mass 66.2 ± 4.7 kg) completed a 5 v 5 SSG using two repetitions of 8 minutes interspersed by 3 minutes of passive recovery. To evaluate temporal changes in performance, the data were analysed across 4 minutes quarters. Physical performance parameters included the total distance covered (TDC), the frequency of sprints (>18 km•h-1), accelerations and decelerations (> 2.0 m•s-2 and - 2.0 m•s-2), metabolic power (W•kg-1), training impulse (TRIMP), TDC: TRIMP, number of impacts, and body load. Technical performance parameters included goal attempts, total number of tackles, tackles and interceptions, total number of passes, and passes effectiveness..
    Results
    All physical performance parameters decreased from the first to the last quarter with notable declines in TDC, metabolic power and the frequency of sprints, accelerations and decelerations (P 0.05; trivial ES for 1st v 4th quarters: 0.15 - 0.33)..
    Conclusions
    The data demonstrate that technical performance is maintained despite substantial declines in physical performance during a SSG in elite youth players. This finding may have implications for designing SSG’s for elite youth players to ensure physical, technical and tactical capabilities are optimized. Modifications in player number, pitch dimensions, rules, coach encouragement, for instance, should be included taking into account the main aim of a given session and then focused on overloading physical or technical elements..
    Keywords: Football, Drills, Fatigue, Passing
  • Norimitsu Kinoshita*, Rei Fukuda Page 10
    Background
    Female distance runners are predisposed to thinness for performance reasons and at greater risk for health-related consequences than the general population..
    Objectives
    The aim of the study was to evaluate the secular trends in thinness among competitive distance runners in Japanese high schools with sex-specific comparison..
    Methods
    Body mass index (BMI) were analysed in 9,881 female and 12,786 male runners participating in the annual national road relay races between 1989 and 2014 using the directory of a track and field magazine. The age-specific trends of these variables and the prevalence of thinness were tested by linear and logistic regression, respectively..
    Results
    Although BMI declined significantly among both male and female runners (coefficients: boys, -0.033, -0.030, and -0.032; girls, -0.033, -0.034, and -0.034 [all P
    Conclusions
    The results suggested that severely thin girl runners has steadily increased. Surveys on the health consequences of extreme thinness are necessary for the female adolescent runners..
    Keywords: Thinness, Running, Female Adolescents, Body Mass Index
  • Ahmadreza Askary, Ashtiani, Ali Ghanjal, Monireh Motaqi, Gholam Hossein Meftahi, Boshra Hatef *, Hoda Niknam Page 11
    Background
    Type 2 diabetes (T2DM) patients are subject to muscle weakness.
    Objectives
    The aim of the study was an assessment of electromyographic (EMG) activity of knee muscles during isometric maximal voluntary contraction in the different disease durations of T2DM.
    Methods
    Eighteen patients with less than 10 years and twelve patients with more than 10 years of T2DM were compared with nineteen matched healthy control subjects. EMG of flexor and extensor muscles of knee concurrently with isometric maximal peak torque of knee flexion and extension at 75 degrees of knee flexion were recorded in three groups.
    Results
    Isometric maximal peak torque of extension and root mean squared (RMS) of vastus lateralis and medial hamstring in the healthy control was significantly higher than both patient groups. Whenever the maximal isometric peak flexion torque was not significantly different between groups, the mean power frequency (MPF) of flexor muscles especially medial hamstrings were higher in the short-term T2DM than healthy control groups. The two factors, gender and age, had significant effect on maximal peak torque and RMS of knee muscles.
    Conclusions
    EMG could show the effect of T2DM, gender and age on knee muscles activity. It seems that the medial hamstring was the most sensitive muscle of knee compartment to show the effect of T2DM and difference of short and long-term T2DM in EMG study.
    Keywords: Type 2 Diabetes Mellitus_Isometric Maximal Peak Torque_Electromyography_Knee
  • Pardis Noormohammadpour, Alireza Hosseini Khezri, Pawe? Linek, Mohammad Ali Mansournia, Alireza Hassannejad, Ali Younesian, Farzin Farahbakhsh, Ramin Kordi * Page 12
    Background
    Low back pain (LBP) is a common complaint amongst adolescent athletes. While different studies have shown association between LBP and trunk muscle thickness in the general population, few articles have studied it in adolescent athletes.
    Objectives
    The aim of this study is to compare lateral abdominal muscle thickness and function, and cross sectional area (CSA) of lumbar multifidus (LM) in adolescent soccer players with and without LBP.
    Methods
    In total, 28 adolescent soccer players with and without LBP, from the premier league participated in this study. The thickness of external oblique, internal oblique and transversus abdominis and the CSA of the LM muscles at L4 level on both sides were measured at rest and contraction via ultrasound imaging (USI). In addition, leg length discrepancy, hamstring flexibility, active lumbar forward flexion, and isometric muscle endurance of trunk extensors were measured in both groups. (study design/setting: case control study).
    Results
    The mean (SD) age in LBP group and non-LBP group were 14.0 (1.1) and 14.1 (0.9) years, respectively. There was no significant difference in baseline characteristics of participants between groups. Findings showed no significant difference between LBP and non-LBP groups comparing all measured variables.
    Conclusions
    The data obtained support that there is not a correlation between abdominal muscle thickness and CSA of the lumbar multifidi and LBP in adolescent soccer players. These findings suggest that other factors rather than the thickness of deep trunk muscles may play a more significant role in the etiology of LBP in adolescent soccer players.
    Keywords: Adolescent Athlete, Soccer Player, Low Back Pain, Transversus Abdominis, Lumbar Multifidus
  • Behzad Bazgir, Mojtaba Rezazadeh Valojerdi, Hamid Rajabi, Rouhollah Fathi, Seyed Mojtaba Ojaghi, Mohammad Kazem Emami Meybodi, Gabriel R. Neto, Mostafa Rahimi, Alireza Asgari * Page 13
    Background
    Recently it has been suggested that low intensity (LI) resistance exercise (RE) alone or in combination with blood flow restriction (BFR) can be applied for cardiovascular function improvement or rehabilitation.
    Objectives
    The aim of the present study was to investigate the acute effects of LI eccentric RE with and without BFR on heart rate (HR), rate pressure product (RPP), blood pressure (BP) parameters [systolic, diastolic, and mean arterial pressure (MAP)], oxygen saturation (SpO2) and rate of perceived exertion (RPE).
    Methods
    In a semi-experimental study 16 young adults (26.18 ± 3.67 years) volunteered and performed LI (30% maximum voluntary contraction) eccentric RE alone or combined with BFR.
    Results
    The results indicated that HR, RPP, and RPE increased significantly within both groups (P 0.05). Furthermore, studied parameters did not vary amongst different groups (P > 0.05).
    Conclusions
    It is concluded that LI eccentric RE with BFR positively regulated the hemodynamic and cardiovascular responses. Therefore, the eccentric RE combined with BFR seems to be a good option for future studies with the aim of time efficacy, since it alters these parameters within normal values.
    Keywords: Cardiovascular System, Hemodynamics, Resistance Training, Vascular Occlusion