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sexta-feira, 2 de março de 2012
J Sports Sci. 2012 Mar;30(6):547-53.
Isokinetic hamstrings-to-quadriceps peak torque ratio: The influence of sport modality, gender, and angular velocity.
Sourcea Departamento de Fisiologia , Universidade Federal de São Paulo (UNIFESP) , São Paulo , Brazil.
AbstractAbstract The purpose of this study was to determine differences in hamstrings-to-quadriceps (H/Q) peak torque ratios evaluated at different angular velocities between men and women who participate in judo, handball or soccer. A total of 166 athletes, including 58 judokas (26 females and 32 males), 39 handball players (22 females and 17 males), and 69 soccer players (17 females and 52 males), were evaluated using an isokinetic dynamometer. The H/Q isokinetic peak torque ratios were calculated at angular velocities of 1.05 rad · s(-1) and 5.23 rad · s(-1). In the analysis by gender, female soccer players produced lower H/Q peak torque ratios at 1.05 rad · s(-1) than males involved in the same sport. However, when H/Q peak torque ratio was assessed at 5.23 rad · s(-1), there were no significant differences between the sexes. In the analysis by sport, there were no differences among females at 1.05 rad · s(-1). In contrast, male soccer players had significantly higher H/Q peak torque ratios than judokas (66 ± 12% vs. 57 ± 14%, respectively). Female handball players produced significantly lower peak torque ratios at 5.23 rad · s(-1) than judokas or soccer players, whereas males presented no ratio differences among sports At 5.23 rad · s(-1). In the analysis by velocity, women's muscular ratios assessed at 1.05 rad · s(-1) were significantly lower than at 5.23 rad · s(-1) for all sports; among men, only judokas presented lower ratios at 1.05 rad · s(-1) than at 5.23 rad · s(-1). The present results suggest that sport modality and angular velocity influence the isokinetic strength profiles of men and women.
Asian J Sports Med. 2010 Mar;1(1):29-34.
Pre-participation Cardiovascular Screening of Elderly Wrestlers.
Sports Medicine Research Center, Tehran University of Medical Sciences, Tehran, IR Iran.
PURPOSE:Sudden death of a competitive athlete is a tragedy that is usually caused by a previously unsuspected cardiovascular disease. The aim of this study was to clarify the role of noninvasive testing in pre-participation cardiovascular evaluation of elderly wrestlers.
METHODS:We included 63 Iranian elderly wrestlers who participated in Tehran international elderly wrestlers' preparation camping by census method. A questionnaire including past medical and family history as well as coronary risk factors was filled out and then a complete physical examination of the cardiovascular system was done by an internist for all wrestlers. Electrocardiogram (ECG), complete echocardiographic examination and then symptom limited exercise test were performed and reported by the cardiologists who did not know the other examinations results.
RESULTS:Exertional dyspnea and typical chest pain (FC=I or II) were present in 5% and 1.7% of the examinees, respectively. There were one or more risk factors in 64.5% of the cases. Cardiovascular examination revealed abnormal heart sounds in 27.1%. ECG showed ischemic changes in 13.6% and premature atrial contractions and premature ventricular contractions in 11.4%. Echocardiography showed mild left ventricular systolic dysfunction in 3.4%, regional wall motion abnormality in 8.5%, valvular disease in 32.3%, diastolic dysfunction in 45.7%, and left ventricular hypertrophy in 16.9% of the cases. Exercise test results were negative, equivocal, positive and highly positive in 70.4%, 15.8%, 5.2%, and 8.6% of cases, respectively.
CONCLUSION:Beside physical examination, pre-participation screening of elderly wrestling athletes with ECG and exercise testing is feasible and recommended in the presence of coronary risk factors or cardiac symptoms. Echocardiography can also be recommended to detect other relevant abnormalities when there is a clue in the standard history, physical examination or ECG.
Asian J Sports Med. 2010 Mar;1(1):23-8.
Injury rates in Iranian taekwondo athletes; a prospective study.
Sports Medicine Research Center, Tehran University of Medical Sciences, IR Iran.
PURPOSE:Taekwondo, as the most popular martial art among Iranian sportsmen, might lead to injury for the athletes of this sport during competitions. We decided to report the incidence rate of injuries sustained by the athletes of this sport during national competitions.
METHODS:All competitions of Iran national championship taekwondo league in 2006-2007 with 204 athletes were observed prospectively to detect the occurrence of injuries. The severity of injuries was classified into four groups (mild, moderate, severe, and critical) according to the involvement of medical care team in the contest, ability of the athletes to resume and duration of probable absence of injured athletes from future competitions and training sessions. Athlete-Exposure (A-E) was defined as the number of competitions multiplied by two. On this base, the rate of injury incidence per 1000 A-Es, the rate of injuries per time unit and the rate of injury occurred for each 100 athletes were considered as the major outcomes of this study.
RESULTS:Of totally 1,338 A-Es, 93 injuries were recorded during the competitions. The rate of injury incidence was found to be 69.5 injuries per 1000 A-Es and the rate of injuries per minute of competitions was 0.023 which corresponded to 23.3 injuries per 1000 minutes of competitions. 45.6 injuries were occurred for each 100 athletes during the course of competitions. The most frequent injuries were mild (68.8%) and critical injuries (24.7%), followed by moderate and severe injuries; 4.3% and 2.1%, respectively.
CONCLUSION:The rate of injury we found was lower than that of western countries. In spite of finding the lower limbs as the most frequent place of injuries in other studies, we found the upper limbs as the most predisposed place of injuries which might be due to difference in the method of combat of Iranian athletes with other athletes.
Asian J Sports Med. 2010 Jun;1(2):117-21.
An addendum to injury rates in Iranian taekwondo athletes; a prospective study.
SourceExRA, Inc., Ann Arbor, MI, USA.
PURPOSE:The objective of this study was to compare the Iranian taekwondo-in statistically in terms of total injury rates to international counterparts as gleaned from the extant literature.
METHODS:The Iranian sample consisted of 204 male taekwondo-in participating in the national championship. The international sample included the participants in national and international tournaments. Validated standard questionnaires were employed at all tournaments to collect injury data that were always diagnosed by the respective tournament physicians. An injury was defined as any circumstance for which assistance was sought from the medical personnel. In addition to injury rates, 95% confidence intervals (CIs) around the rates were computed. To assess which group was at higher risk, odds ratios were calculated, including the 95%CIs.
RESULTS:Compared to Greek counterparts, the injury rate for the Iranian taekwondo-in was statistically significantly higher. The Iranians were also at a higher risk to incur an injury: OR = 11.2 (95%CI: 6.60-18.88, P<0.001, CLR = 2.86). When comparing the Iranian taekwondo-in to their colleagues competing at the 1999 World Championships, the former recorded a statistically significantly lower injury rate but the latter were not at a higher risk (OR = 0.61, 95%CI: 0.41-0.91, P=0.014, CLR = 2.20).
CONCLUSION:A statistical comparison of total injury rates in Iranian and international taekwondo-in revealed no difference between the two groups. However, what is of concern is that the total injury rate across taekwondo studies is significantly higher than those reported for American football.
Asian J Sports Med. 2011 Sep;2(3):205-10.
Investigating Two Different Training Time Frames during Ramadan Fasting.
SourceSports Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.
PURPOSE:Muslim athletes may continue training and competing while they are fasting. There is a concern about negative effects of fasting on sports performance. This study aimed to investigate the influence of two training time frames on athletes' body composition and performance during Ramadan fasting.
METHODS:An observational study was conducted and thirty four male volunteer athletes from different sports including volleyball, karate, taekwondo and football were assigned in two groups. The first group included 14 elite athletes who during Ramadan voluntarily participated in training sessions at 1 hour before Iftar (BI) and the second group of 20 elite athletes who during Ramadan participated in training sessions at 3 hours after Iftar (AI). Testing was performed one week before; in the first and fourth weeks of Ramadan and one week after Ramadan. Weights, heights and skinfold thickness were assessed at each time point and body mass index was calculated. Each player was assessed for agility and explosive strength as well.
RESULTS:The mean weight and body mass index of both groups decreased significantly during Ramadan (P<0.001). Performance variables were not negatively affected by fasting in BI or AI group athletes.
CONCLUSIONS:Weight reduction might come with either BI or AI training schedules in Ramadan. Daytime or evening training did not inversely affect the agility and power performances in a group of elite athletes during Ramadan fasting.
Asian J Sports Med. 2011 Mar;2(1):31-6.
Martial arts: time needed for training.
Department of Physical Medicine & Rehabilitation, Emory University, School of Medicine, Atlanta, Georgia, USA.
PURPOSE:To measure the time needed to teach a series of martial arts techniques to proficiency.
METHODS:Fifteen volunteer subjects without any prior martial arts or self-defense experience were recruited. A panel of martial arts experts selected 21 different techniques including defensive stances, arm blocks, elbow strikes, palm strikes, thumbs to eyes, instep kicks and a carotid neck restraint. The critical elements of each technique were identified by the panel and incorporated into a teaching protocol, and then into a scoring system. Two black belt martial arts instructors directed a total of forty-five 45-minute training sessions. Videotaped proficiency testing was performed weekly. The videotapes were reviewed by the investigators to determine the proficiency levels of each subject for each technique.
RESULTS:The techniques were rated by the average number of training sessions needed for an individual to develop proficiency in that technique. The mean number of sessions necessary to train individuals to proficiency ranged from 27 to 38.3. Using this system, the most difficult techniques seemed to be elbow strikes to the rear, striking with thumbs to the eyes and arm blocking.
CONCLUSIONS:In this study 29 hours of training was necessary to train novice students to be proficient in 21 offensive and defensive martial arts techniques. To our knowledge, this is the first study that attempts to measure the learning curves involved when teaching martial arts techniques.
Luminescence. 2012 Feb 24. doi: 10.1002/bio.2349. [Epub ahead of print]
Effects of dehydration on immune functions after a judo practice session.
Chishaki T, Umeda T, Takahashi I, Matsuzaka M, Iwane K, Matsumoto H, Ishibashi G, Ueno Y, Kashiwa N, Nakaji S.