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Quem sou eu

São Paulo, São Paulo, Brazil
Professor da EEFE-USP; Praticante e Pesquisador de Judô; Preparador físico de atletas de modalidades esportivas de combate.

Arquivo do blog

sexta-feira, 19 de agosto de 2011

EMG em boxeadoras

Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2011 May;27(2):253-6.

Women boxing athletes' EMG of upper limbs and lumbar muscles in the training of air striking of straight punch
[Article in Chinese]

Zhang RH, Kang ZX.

Department of Human Sports Science, Shenyang Sport University, Shenyang 110102, China. rhzhang75@yahoo.com.cn

OBJECTIVE: To study training effect of upper limbs and lumbar muscles in the proceed of air striking of straight punch by analyzing boxing athletes' changes of electromyogram (EMG).
METHODS: We measured EMG of ten women boxing athletes' upper arm biceps (contractor muscle), upper arm triceps (antagonistic muscle), forearm flexor muscle (contractor muscle), forearm extensor muscle (antagonistic muscle), and lumbar muscles by ME6000 (Mega Electronics Ltd.). The stipulated exercise was to do air striking of straight punch with loads of 2.5 kg of dumbbell in the hand until exhausted.
RESULTS: In the proceed of exercise-induce exhausted, the descend magnitude and speed of median frequency (MF) in upper limb antagonistic muscle exceeded to contracting muscle, moreover, the work percentage showed that contractor have done a larger percentage of work than antagonistic muscle. Compared with world champion's EMG, the majority of ordinary athletes' lumbar muscles MF revealed non-drop tendency, and the work percentage showed that lumbar muscles had a very little percentage of work.
CONCLUSION: After comparing the EMG test index in upper limb and lumbar muscle of average boxing athletes with that of the world champion, we find the testees lack of the training of upper limb antagonistic muscle and lumbar muscle, and more trainings aimed at these muscles need to be taken.

Mínima massa corporal de atletas de luta olímpica

Ann Nutr Metab. 2011 Aug 12;58(3):245-249. [Epub ahead of print]

Validity of the Current NCAA Minimum Weight Protocol: A Brief Review.

Loenneke JP, Wilson JM, Barnes JT, Pujol TJ.

Department of Health and Exercise Science, The University of Oklahoma, Norman, Okla., USA.

Historically, collegiate wrestlers have been associated with utilizing rapid weight loss methods to reach a desired weight class. Following three deaths in 1997, the National Collegiate Athletic Association (NCAA) implemented a program which prevents wrestlers from wrestling below a minimum weight (MW) of 5% body fat. Although numerous studies have investigated adolescent wrestlers, few have investigated collegiate wrestlers using the methods outlined by the NCAA. The purpose of this review paper is to outline potential problems with the current NCAA protocol as well as critique studies investigating the validity of methods to assess MW.

Concussão e MMA

J Neurol Sci. 2011 Aug 15. [Epub ahead of print]

The King-Devick test and sports-related concussion: Study of a rapid visual screening tool in a collegiate cohort.

Galetta KM, Brandes LE, Maki K, Dziemianowicz MS, Laudano E, Allen M, Lawler K, Sennett B, Wiebe D, Devick S, Messner LV, Galetta SL, Balcer LJ.

Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.

OBJECTIVE: Concussion, defined as an impulse blow to the head or body resulting in transient neurologic signs or symptoms, has received increasing attention in sports at all levels. The King-Devick (K-D) test is based on the time to perform rapid number naming and captures eye movements and other correlates of suboptimal brain function. In a study of boxers and mixed martial arts (MMA) fighters, the K-D test was shown to have high degrees of test-retest and inter-rater reliability and to be an accurate method for rapidly identifying boxers and mixed martial arts fighters with concussion. We performed a study of the K-D test as a rapid sideline screening tool in collegiate athletes to determine the effect of concussion on K-D scores compared to a pre-season baseline.
METHODS: In this longitudinal study, athletes from the University of Pennsylvania varsity football, sprint football, and women's and men's soccer and basketball teams underwent baseline K-D testing prior to the start of the 2010-11 playing season. Post-season testing was also performed. For athletes who had concussions during the season, K-D testing was administered immediately on the sidelines and changes in score from baseline were determined.
RESULTS: Among 219 athletes tested at baseline, post-season K-D scores were lower (better) than the best pre-season scores (35.1 vs. 37.9s, P=0.03, Wilcoxon signed-rank test), reflecting mild learning effects in the absence of concussion. For the 10 athletes who had concussions, K-D testing on the sidelines showed significant worsening from baseline (46.9 vs. 37.0s, P=0.009), with all except one athlete demonstrating worsening from baseline (median 5.9s).
CONCLUSION: This study of collegiate athletes provides initial evidence in support of the K-D test as a strong candidate rapid sideline visual screening tool for concussion. Data show worsening of scores following concussion, and ongoing follow-up in this study with additional concussion events and different athlete populations will further examine the effectiveness of the K-D test.

Treinamento intervalado de alta intensidade aplicado a lutadores de wrestling

Embora o protocolo adicional não seja específico, o estudo é interessante.

J Strength Cond Res. 2011 Aug 16. [Epub ahead of print]

Physiological and Performance Changes From The Addition of a Sprint Interval Program to Wrestling Training.

Farzad B, Gharakhanlou R, Agha-Alinejad H, Curby DG, Bayati M, Bahraminejad M, Mäestu J.

Department of Physical Education and Sports Sciences, School of Humanity Sciences, Tarbiat Modares University, Tehran, Iran; 2Overtime School of Wrestling, Naperville, Illinois; 3Physical Fitness Assessment and Improvement Center, National Olympic and Paralympic Academy, Tehran, Iran; and 4Institute of Sport Pedagogy and Coaching Sciences, Centre of Behavioural and Health Sciences, University of Tartu, Tartu, Estonia.

Farzad, B, Gharakhanlou, R, Agha-Alinejad, H, Curby, DG, Bayati, M, Bahraminejad, M, and Mäestu, J. Physiological and performance changes from the addition of a sprint-interval program to wrestling training. J Strength Cond Res 25(9): 2392-2399, 2011-Increasing the level of physical fitness for competition is the primary goal of any conditioning program for wrestlers. Wrestlers often need to peak for competitions several times over an annual training cycle. Additionally, the scheduling of these competitions does not always match an ideal periodization plan and may require a modified training program to achieve a high level of competitive fitness in a short-time frame. The purpose of this study was to examine the effects of 4 weeks of sprint-interval training (SIT) program, on selected aerobic and anaerobic performance indices, and hormonal and hematological adaptations, when added to the traditional Iranian training of wrestlers in their preseason phase. Fifteen trained wrestlers were assigned to either an experimental (EXP) or a control (CON) group. Both groups followed a traditional preparation phase consisting of learning and drilling technique, live wrestling and weight training for 4 weeks. In addition, the EXP group performed a running-based SIT protocol. The SIT consisted of 6 35-m sprints at maximum effort with a 10-second recovery between each sprint. The SIT protocol was performed in 2 sessions per week, for the 4 weeks of the study. Before and after the 4-week training program, pre and posttesting was performed on each subject on the following: a graded exercise test (GXT) to determine VO2max, the velocity associated with VO2max (νVO2max), maximal ventilation, and peak oxygen pulse; a time to exhaustion test (Tmax) at their νVO2max; and 4 successive Wingate tests with a 4-minute recovery between each trial for the determination of peak and mean power output (PPO, MPO). Resting blood samples were also collected at the beginning of each pre and posttesting period, before and after the 4-week training program. The EXP group showed significant improvements in VO2max (+5.4%), peak oxygen pulse (+7.7%) and Tmax (+32.2%) compared with pretesting. The EXP group produced significant increases in PPO and MPO during the Wingate testing compared with pretesting (p < 0.05). After the 4-week training program, total testosterone and the total testosterone/cortisol ratio increased significantly in the EXP group, whereas cortisol tended to decrease (p = 0.06). The current findings indicate that the addition of an SIT program with short recovery can improve both aerobic and anaerobic performances in trained wrestlers during the preseason phase. The hormonal changes seen suggest training-induced anabolic adaptations.