Respostas fisiológicas no kata e no kumite do karate

Sport Sci Health. 2012 Dec;8(2-3):81-85. Epub 2012 Nov 17.

Metabolic and hormonal responses to a single session of kumite (free non-contact fight) and kata (highly ritualized fight) in karate athletes.

Benedini S, Longo S, Caumo A, Luzi L, Invernizzi PL.

Source

Department of Sport, Nutrition and Health Sciences, Università degli Studi di Milano, Milan, Italy ; Research Center of Metabolism IRCCS Policlinico San Donato Milanese, Milan, Italy ; Research Center of Metabolism, Piazza Edmondo Malan, 20097 San Donato Milanese, Milan, Italy.

Abstract

BACKGROUND:

Several studies report martial arts as a good model for investigating neuroendocrine responses to competitive fighting. However, little is known on the metabolic responses elicited by elite athletes during fighting. In particular, the metabolic picture in elite athletes of martial arts is little known.

AIM:

In the present study, our aim was to investigate the acute effects of a session of karate practice on the glucose-insulin system.

SUBJECTS AND METHODS:

Ten healthy individuals (6M/4F; BMI: 22.1 ± 0.7 kg/m(2); 21.9 ± 1.1 years, mean ± SE) who practice karate in national or international competitions were enrolled. All participants completed two experimental trials in a randomised-crossover fashion. A basal blood sample was collected from each athlete to assess plasma glucose, insulin, cortisol, testosterone and catecholamines, before karate training session. In two separate days, another blood sample was collected from each participants after 3 min of real fighting (kumite) and 3 min of ritualized simulation of combat (kata).

RESULTS:

In both trials, plasma glucose resulted to be higher at the end the of performance compared to the basal (p < 0.001 after kumite and p < 0.02 after kata). In contrast, insulin was similar in the basal and after physical activity in the two trials. Catecholamines were higher after kata and kumite sessions with respect to the basal values (p < 0.04) and, in particular, epinephrine post-kumite values were much greater than those measured after kata.

CONCLUSIONS:

Our results indicate that unlike performances of karate (kumite and kata) elicit different plasma glucose increases. In particular, we found that glucose and epinephrine concentrations increased more after kumite than after kata.

Desidratação e ganho de peso em atletas de MMA

J Strength Cond Res. 2013 Feb 22. [Epub ahead of print]

Dehydration and Acute Weight Gain in Mixed Martial Arts Fighters Prior to Competition.

Jetton AM, Lawrence MM, Meucci M, Haines TL, Collier SR, Morris DM, Utter AC.

Source

1Department of Health, Leisure, and Exercise Science; Appalachian State University, Boone, North Carolina, 28608. 2Department of Health Sciences, University of Rome 'Foro Italico', Rome, Italy.

Abstract

ABSTRACT: The purpose of this study was to characterize the magnitude of acute weight gain (AWG) and dehydration in mixed martial arts (MMA) fighters prior to competition. Urinary measures of hydration status and body mass were determined ∼24 h prior and then again ∼2 h prior to competition in 40 MMA fighters (Mean ± SE, age: 25.2 ± 0.65 yr, height: 1.77 ± 0.01 m, body mass: 75.8 ± 1.5 kg). AWG was defined as the amount of body weight the fighters gained in the ∼22 h period between the official weigh-in and the actual competition. On average, the MMA fighters gained 3.40 ± 2.2 kg or 4.4% of their body weight in the ∼22 h period prior to competition. Urine specific gravity significantly decreased (P < 0.001) from 1.028 ± 0.001 to 1.020 ± 0.001 during the ∼22 h rehydration period. Results demonstrated that 39% of the MMA fighters presented with a Usg of greater than 1.021 immediately prior to competition indicating significant or serious dehydration. MMA fighters undergo significant dehydration and fluctuations in body mass (4.4% avg.) in the 24 h period prior to competition. Urinary measures of hydration status indicate that a significant proportion of MMA fighters are not successfully rehydrating prior to competition and subsequently are competing in a dehydrated state. Weight management guidelines to prevent acute dehydration in MMA fighters are warranted to prevent unnecessary adverse health events secondary to dehydration.

Antecipação no karate

Q J Exp Psychol (Hove). 2013 Feb 26. [Epub ahead of print]

Timing of in situ visual information pick-up that differentiates expert and near-expert anticipation in a complex motor skill.

Rosalie SM, Müller S.

Source

a Discipline of Exercise Sciences , RMIT University , Bundoora , VIC , Australia.

Abstract

The timing of visual information pick-up for visual anticipation was examined by comparing the capability of multiple skill groups, expert and near-expert karate athletes and novices, to block attacks using an in situ temporal occlusion paradigm. Participants stood facing a karate opponent and then attempted to block attacks (kicks and punches), whilst their vision of attacks was occluded: (a) prior to onset of opponent motion (O1), (b) after preparatory head movement (O2), and (c) after initiation of the attacking motion (O3). A no occlusion control condition provided complete vision of attacks (O4). Results revealed that expert anticipation was not significantly different to that of near-experts at O1, but was significantly different to the other group across O2-O4. Expert anticipation, however, was significantly above chance across all occlusion conditions, but near-experts performed above chance at O3 and O4, whilst novices were better than chance at O4. Unexpectedly, unique evidence was found that expert anticipation could be differentiated from near-expert anticipation in the earliest occlusion condition, where it was found that only experts were capable of using visual information from a static opponent to anticipate and block attacks above chance. The findings further understanding of expert visual anticipation to guide motor skills beyond existing expert-novice comparisons.