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Judo is a complex sport where different anthropological parameters determine performance. Judo, as a sport is not well known in India. There is evident lack of data concerning the anthropological determinants of judo players. This study was conducted to determine the anthropometric profile and Special Judo Fitness levels of judokas.
This cross sectional study was conducted on 31 judo players. Anthropometric profile was assessed by measuring height, weight, body mass index, body circumferences at seven sites, seven site skin fold thickness and body fat percentage as per standard accepted protocol. Special Judo Fitness Test – a specific test to evaluate the judo athlete's physical condition was applied. Statistical analysis done using Student's unpaired ‘t’ test and correlation by Karl Pearson's correlation coefficient.
Out of 31 judo players 20 had ≤5 yrs of judo practice (A group) and 11 >5 yrs of judo (B group). Anthropometric findings of both the judo groups were the same. Body fat has negative correlation (r =-0.690, P<0.05) with performance in SJFT. Observations during and after special judo fitness test were also similar.
Long term training has a minimal effect on anthropometry. Judo athletes of similar age when submitted to the same training type tend to show equal performance in the game and fitness levels after certain years of training. We also confirm existence of negative correlation between body fat and performance.
Judo is a Japanese art and an Olympic sport, in which besides technical skill and tactical strategies, conditional (physical and physiological) characteristics are also indispensable for success in competition and for training . Competitive judo can be described as a combative, high intensity sport in which the athlete attempts to throw the opponent onto his back or to control him during groundwork combat. Both attempts depend on specific techniques and tactical skills with the support of good physical fitness . Being aware of the anthropometric and physiological characteristics of an elite athlete will pave the way for his success . As judo is a weight-classified sport, high level judo players should have low body fat. It has been suggested that percentage of body fat may be a discriminator for success .
Judo is the sport in which movements are powerful, delivered in a short period of time, usually against the force of the opponent. It is a sport of changeable intensity of effort. During contest, the non-stop periods of maximum or submaximum intensity are separated by longer or shorter breaks . Fitness levels in judokas are evaluated based on special judo fitness test (SJFT) which gives effort tolerance levels in them. This test is of intermittent character with breaks between the test and uses a specific movement (throw) of the game called ippon-seoi-nage. The evaluation of physical characteristics is an important part of the training process because it gives information about the variables that need to be improved and about the effectiveness of a given training program. Hence, this study was undertaken to define and interpret the possible anthropological determinants, and special judo fitness levels in Indian judo practitioners.
The present study was a cross sectional study conducted in the Department of Physiology, Jawaharlal Nehru Medical College, Belgaum between January 2009 and December 2009. Using universal sampling, data was collected from 31 Judo players practicing regularly for a minimum period of 3 years and who were in the age group of 18-25yrs. Information about their practice schedule, number of players and their availability was collected from the Judo coaches. Descriptive data of the participant's age, medical history, training schedule regarding number of years of judo practice, number of days in a week, number of hours per day, dietary history were obtained by interviewing the participants. The study was approved by the Ethical and Research Committee of the institution. Players were briefed about the nature of the study and written informed consent was obtained.
The participants were divided into two groups depending on number of years of judo training. Judo A group consisted of players with ≤ 5 years of Judo and Judo B group consisted of the senior players with > 5 years of training. Both groups had been exposed to similar training regimens and the diet given to them was similar as all of them resided in the same sports hostel. Anthropometric measurements included: Height (m) was measured by a commercial stadiometer, Weight (kg) was recorded by digital scale with an accuracy of ±100g, body mass index (BMI) was calculated from height and weight using Quetelet's equation:
Body Circumferences (cm) at seven sites (relaxed arm, flexed arm, forearm, wrist, thigh, calf and chest) were identified and measured using measuring tape as per standard protocol . Skin fold thickness (mm) was measured by Herpenden skin fold calipers (Anand agencies, Pune). Seven sites (triceps, subscapular, midaxillary, abdomen, suprailiac, medial calf and proximal thigh) were identified on the right side of the body and body density was calculated. Body fat % was calculated using SIRI'S EQUATION [6, 7].
Two judokas (uke) of similar stature and body mass of the performer are positioned at 6m of distance of one another, while the performer of the test (tori) is three meters of distance from the judokas that will be thrown. The test is divided into three periods of 15s (A), 30s (B) and 30s (C) with intervals of 10s. During each one of the periods the performer throws the partners using the ippon-seoi-nage technique as much as possible. Immediately after and 1 minute after the end of the test, the athlete's heart rate is verified. The total of throws accomplished in this period is added and an index is calculated.
Statistical analysis involved quantitative variables summarized through mean and standard deviation. Difference between the mean of the two groups was tested using Students unpaired ‘t’ test, where significance of the p value was < 0.05 To evaluate strength of association between performance (number of throws) in special judo fitness test and body weight/body fat among Judo players Karl Pearson's correlation coefficient was calculated.
In this study out of 31 players 20 fall in group A and 11 in group B, depending on number of years of Judo training. Table 1 shows the anthropometrical results from group A compared to group B which shows that no significant difference was found for these variables, Except that the height of players of A group was higher than B group players with statistically significant difference (P= 0.047).
Special judo fitness test results depicted in Table 2 show no significant difference in performance. Figures 1 and and22 shows relationship between Body weight, body fat % and number of throws in the Special Judo fitness test. Pearson correlations (r), number of subjects (n). Body fat had a significant negative correlation with the performance in SJFT.
In the present study the height of A group was higher than B group judo players with a statistically significant difference. A study done on Polish judo players concluded that the body height of the fighters was moderately connected with the preferred techniques in combat. Hand techniques were preferred by short and medium-height fighters and leg techniques by tall fighters . In this study, there was no significant difference in body weight of the two judo groups and a non significant negative correlation (r=-0.09) (Fig. 1) between body weight and performance in the SJFT was observed. Few studies have got a significant difference indicating that heavier athletes present a lower anaerobic power in activities that involve throwing opponents from the same category [10, 11].
Despite there being no difference between the groups in anthropometrical characteristics, it is important to note that the body fat percentage was the same in both groups but, when compared to data on non players of same age from literature there was a huge difference that indicates that judo players were lean, this supports the assumption that judo players try to maximize lean body mass and minimize fat mass. It may also be just a reflection of physiological adaptations to long-term judo training [11–14]. Previous studies give the body fat percentage values of different judo players as follows: Hungarian team(8.9%), Canadian team (12.3%), Japanese (16.2%), Brazilian team (13.7%) and North American team (8.3%) . Body fat % in this study was (11.9% and 13.8%) for A and B group respectively. Negative correlation (r = -0.690) of body fat % and motor performance (number of throws in SJFT) (Fig. 2) observed in the present study correlates with other studies [10, 15, 16]. Indicating that as the fat % increases the performance of the athlete comes down. Difference in mean group indices of body mass index of two judo groups turned out to be statistically insignificant. This result corroborates with a result of study done on senior and junior players of Poland . One study reported that elite judo athletes had higher circumferences (flexed arm, forearm, wrist, and medial calf) than non-elite judo players . In the present study both groups had similar values in all these circumference measures. This finding corroborated with one of the studies, which reported that there were no differences in circumferences between the competing vs. non-competing judokas . A study on Brazilian elite and non elite players showed no difference in any skinfold measure which was a finding in this study also . This might be due to similar training sessions for all the players.
The best proof of physical capacity is the practice of the sport. Therefore, the effects of endeavor in this discipline may be assessed on the basis of the competitor's maximum metabolic abilities clashing with each other during combats . In this study in SJFT not much difference was seen in number of throws, heart rate or SJFT Index between two judo groups. This finding was similar to the studies done before [15, 18] which indicates the same level of development and similar cardiovascular stress during this test for both groups. Recently a normative table was proposed to classify performance in the SJFT . The athletes of the present study are classified as good in all variables in this test (number of throws, heart rate after, heart rate 1 min after, and index). Two studies reported a higher number of throws and a lower index in judo players (Brazilian and Polish) at the national level compared to athletes at a lower level [10, 20]. A decrease in the heart rate (HR) at the end of the test with a given number of throws proves the efficiency of the cardiovascular function in the two groups. Decrease in the same heart rate after 1 min of the test proves better regeneration and reflects the improvement in the aerobic function.
Limitations of this study are a small sample size and inability to evaluate physiological and biochemical features of our athletes. The data provides the judo player with information on ideal profile and where training might be directed to compensate for areas where the athlete is below average for successful judo players. A judo player who does not match the ideal profile can still succeed through improved or superior techniques and tactics.
The following conclusions can be drawn from this study: long term training has a minimal effect on anthropometry. Physical components are not discriminatory to the performance of Judo athletes. The higher the fat percentage, the lower is the performance in activities involving body displacement (negative correlation). In SJFT no significant difference was found among judo groups in the performance indicating that athletes around the same age submitted to the same training type tend to have similar performance in the test after certain years of training.
Further studies with large sample size should be carried out and difference between sexes in terms of anthropometry and performance should be focused. Physiological and biochemical features which might affect performance should be studied.
We thank all participants, coaches and parents for their kind participation in the study
Conflict of interests: None