THE PHYSIOLOGICAL COMPOSITION OF ELITE JUDO PLAYERS
by Wayland Pulkkinen
author of The Sport Science of Elite Judo Athletes
from Hatashita Sports)
(i) An Analysis of Judo Mechanics and the Competitive Judo Match
Movement patterns within judo require competitors to grapple the judo costumes (gi) via the lapel, collar and/or sleeve in order to off-balance (kuzushi) each other enough to execute a throw. Sparring either occurs in standing or ground situations, depending upon individual player strategy and the natural development of the match. In standing competition, points are awarded based on the degree of skill demonstrated in a takedown (throw), and range from a take-down to the backside (koka) to a high amplitude throw flat to the back (ippon). In contrast, ground competition points are also awarded for the length of time a pin is executed for a minimum of 10 seconds (koka) to a maximum of 25 seconds (ippon). Furthermore, a automatic victory is awarded when a submission hold is executed via a strangulation or joint manipulation, whereby the opponent either voluntarily submits or is unable to continue competition (ie. becomes unconscious or injured). Thus, immediate victory can be achieved through the awarding of a full-point or "ippon" in either standing or ground strategies. The relative contribution of standing to ground sparring essentially is determined by the strategies of each player. Different tactics will be employed by different judoka depending on individual strengths and weaknesses.
Three officials operate on the mat surface, with the primary decisions made by the acting referee under the observations of two judges concomitantly. All calls must have the support of at least 2 of the 3 officials in order for them to be passed, therefore the two sideline judges may overrule an acting referee if an incorrect call is made. Rules and regulations governing judo by the International Judo Federation (IJF) require players to be extremely dynamic throughout the match, and thus players are penalized if they become non-combative and/or defensive during the match. In addition, players are also penalized if they voluntarily flee the caution zone of the mat surface in an attempt to avoid an attack. Thus the rules require judo to involve repeated high intensity attacks, and therefore dictate the physiological requirements of each player.
(ii) The Physical Basis of Competitive Judo: Match Dynamics
In order to understand the metabolic and physiological requirements of judo training, a time motion analysis of the competitive match must be completed. The analysis will enable the sport scientist to evaluate the relative energy system contribution during judo activity. Through this approach, optimal training programs will be able to be individualized, thus prescribing ideal intensity and duration of judo activity for training purposes. Most time motion analysis studies and corresponding research has been done on Olympic wrestling, which is similar in the physiological demand and energy cost as Olympic judo. Competitive Olympic wrestling exists in two forms: free-style and Greco-Roman. Although, it has been demonstrated that there are no physiological differences between wrestlers of both free-style and Greco-Roman styles (Horswill et al., 1992). Freestyle wrestling is characteristic of short duration, high intensity, intermittent exercise lasting a total duration of six minutes (2 three minute bouts). This time may be expanded to three minutes, if the two opponents have a tied score, or either wrestler is absent of a three point lead. Therefore, a match may last anywhere from several seconds, to a maximum of six minutes. Anaerobic power is crucial due to the scoring system for both free-style and Greco-Roman wrestling, using explosive techniques which may end the match prior to regulation time (Horswill et al, 1992). Time motion analysis has demonstrated that Olympic (62 kg) wrestlers perform a mean of 16 (3.0-19.5) high intensity action-reaction sequences. Each attack sequence lasts approximately 3.1 seconds (1-8) in duration, with a mean recovery period of 23.6 seconds (Cipriano, 1993). The recovery period involves sub-maximal work, primarily utilizing pushing, pulling and lifting actions, from which the wrestler can receive short term recovery, as well as time to prepare for a following attack. As a result, competitive wrestling activity is extremely dynamic in nature, encompassing repeated explosive movements at a high intensity that alternates with sub-maximal work. Thus the primary energy systems utilized are the anaerobic ATP-CP and lactic systems, within the scope of the aerobic system.
In comparison, Olympic judo is a dynamic, physically demanding sport, requiring a high level of physical conditioning and strength in order to be successful and offset fatigue. Many authorities characterize sport judo as an explosive power sport, requiring tremendous reserves of anaerobic power and capacity, yet operating within a well developed aerobic system (Callister et al., 1991; NCCP, 1990; Sharp et al, 1987; Thomas et. al, 1989; Takahashi, 1992). Judo is characteristic of short duration, high intensity, intermittent exercise lasting a total match period of five minutes for males and four minutes for females. Therefore, it is primarily an anaerobic sport, consisting of all out bursts of activity ranging from a mean time of approximately 10 to 30 seconds of work to 10 to 15 seconds of rest (NCCP, 1990). This would equate to a work to rest ratio of approximately 2:1 or 3:1. The recovery period often involves sub-maximal work, primarily performing grappling or gripping actions between each successive attack sequence. This period allows for a shorter term of recovery, as well as time to prepare for a following attack. Sikorski et al. (1987) categorized periods of contest judo work into four stages: 0-10 seconds, 11-20 seconds, 21-30 seconds and more than 30 seconds. The highest frequency of rest or breaks (80%) lasted in the 0-10 seconds range, with the highest frequency of activity (39%) in the 11-21 seconds range. Furthermore, Sikorski et al. (1987) found the mean time of work activity does not exceed 25 seconds, with a rest period of no more than 10 seconds. Attacks are often initiated within every 10 to 15 seconds of the match. Based on these findings, it can be concluded that the primary source of energy contribution in contest judo is derived from anaerobic glycolysis (Sikorski et al., 1987).
Analysis of World Championships (1981, 1983, 1985); European Championships (1982, 1984, 1985); and Polish Championships (1983, 1984, 1985) by Sikorski et al. (1987) illustrates both the frequency and effectiveness of techniques applied by successful elite judoists. Results were derived from examining all seven male divisions, with a minimum sample size of 54 players in each category. In all three competitions, there was a higher frequency of attacks and a higher frequency of effectiveness of attacks in the first and last minute of a match. Furthermore, light weight categories (-60 kg, -65 kg, -71 kg) tended to initiate attacks more frequently within a 10 second time period, with heavier divisions attacking within a 15 second time period. Surprisingly, the most effective tactical action was penalizing the opponent for passivity in attack. Lighter divisions (-60, -65 and -71 kg) tended to utilize more hand group throws (ie. seoi-nage), which was in contrast to heavier divisions (-78,-86, -95, +95 kg) that utilized more leg group throws (ie. uchi-mata, o-soto-gari) and performed pins more successfully. Overall, the techniques most often applied during contest judo were seoi-nage, o-soto-gari, uchi-mata and ko-uchi-gari.
Analysis of the 1992 Olympic Games in Barcelona substantiates the time constraints of each division. For males, the range for mean match times (minutes : seconds) was lowest with the +95 kg (2:52) to highest with -86 kg division (3:26). Total mean match time for all seven male divisions was 3:00, with a deviation of 20.7 seconds. Female mean match times were very similar to males, with the lowest time for -72 kg (2:39) to the highest mean time for -66 kg (3:04). Total mean match time for females was 2:54, with a deviation of 8.6 seconds. Combined male and female mean match times was 2:57, with a deviation of 3.9 seconds. When examining recent patterns in elite competitions, we see that there is an increasing trend on victories through penalizing one's opponent through non-combativity (refer to figures 1a and 1b).
Figure 1a: Male Mean Match Times from Major Competitive Events (IJF, 2001).
Figure 1b: Female Mean Match Times from Major Competitive Events (IJF, 2001).
As we can see, matches can and do end prior to the set time limit in at least 50 % of all bouts. This appears to occur at or around the 3½ minute mark, with the scoring of "ippon" or full point awarded to the victor. An interesting trend is the significance and the strategy in penalizing one's opponent for passivity or lack of aggression. This is often seen in the practice of "kumi kata" or during the process of "gripping" the opponents uniform. In competition judo, a secure "grip" can be very advantageous in successfully executing a takedown or throw, and often is the main determining factor in whether an executed attack becomes a winning attack. The practical application of this understanding should be to include this type of physical preparation in the training room. Exercises should focus on developing the flexor muscles of the arm and forearm in addition to sustaining both isotonic and isokinetic contractions for brief periods (5-15 seconds) repeatedly in order to develop both familiarity with fatigue and lactate tolerance in the muscles involved. Tactically, gripping should encompass a means of which the athlete can switch and be versatile with their attack in order to change, counter or combine with other subsequent attacks. Our time motion analysis clearly indicates and validates the energy cost of judo performance. Thus one can conclude that the primary energy systems utilized are the anaerobic ATP-CP and lactic systems, within the scope of the aerobic system.
(iii) Physiological Profiles of Elite Judo Athletes
Competitive judo performance utilizes both aerobic and anaerobic energy systems. Physical training for judo competitions emphasizes focusing on both aerobic and anaerobic systems. This section will outline some fundamental adaptations to training, in addition to examining the physiological components of percent body fat, fiber type, aerobic and anaerobic traits of judo players from various national teams.
a) Percent Body Fat of Elite Judo Players
Both the IJF (International Judo Federation) and the IOC (International Olympic Committee) regulations require athletes to compete in set weight categories. Competitors are matched by weight divisions, thus players demonstrate relatively low levels of body fat with a high strength to mass ratio (Takahashi, 1992). Taylor et al (1981) initially determined body fat values for male Canadian players to have a mean value of 12.27%. This was consistent when compared to British male players, whose body fat values were reported at 12.3% (Sharp and Koutedakis, 1987). Thomas et al (1989) reported male Canadian players to range from 6.7% to 15.8%, with a mean of 9.3%. These findings were similar to those by Callister et al (1991), who demonstrated mean body fat values for American male players to be 8.3%, with a standard deviation of 1.0. In all three cases, percent body fat was determined via skinfold thickness. It has been suggested that percent body fat may be a discriminator for success. Callister et al (1991) found that more successful male players (those with more international success or competition points) maintained lower body fat percentages. Although this may be true, it may just be a reflection of physiological adaptations to long-term judo training, in so far as most successful players tended to be older with greater experience. Nevertheless, judo athletes must maintain an ideal body weight and according to IJF rules, weigh in the morning of the competitive event. Thus weight management and corresponding weight loss is a significant factor in determining success of the judo athlete.
b) Fibre Type Composition of Elite Judo Players
Fibre typing can provide information as to the long-term training adaptations of judo players, however, few sources have examined muscle fiber types of elite judo players. A study by Callister et al (1991) sampled muscle tissue from vastus lateralis of male and female U.S. judo players. Myosin ATPase activity was used to determine fiber types histochemically on 12 um thick cross sections. Results indicated that females demonstrated a higher mean value contribution of type I (48.9%) than males (35.7%). Furthermore, females had fewer type IIB mean values (10.5%) than males (26.8%), although, type IIA fibers were similar between males (37.1%) and females (38.5%). These results indicate the anaerobic contribution of judo activity. For males, the distribution of fiber types appears to be somewhat evenly displaced, with greater emphasis placed on type IIA. The practical application to the coach and sport scientist is in understanding the metabolic cost of judo activity. Glycolytic muscle fibers (both type IIA and IIB) need to be trained differently and training programs need to reflect this requirement.
c) Aerobic Requirements of the Elite Judo Player
The aim of aerobic conditioning in judo is to train and improve the working capacity of the heart and its ability to deliver oxygen to the muscles. It has been suggested that the optimal way to improve the oxygen delivery is continuous training, while interval training is more effective in increasing oxygen utilization (Brooks and Fahey, 1985). Applications to judo performance involve a greater recovery from anaerobic work (via lactate metabolism), in addition to a faster re-synthesis of phosphate. By far, the marker of aerobic performance is the calculation of an individuals maximal oxygen uptake (VO2). This process is the highest oxygen uptake the individual can attain during exercise lasting longer than 2 minutes at a maximal intensity (Astrand and Rodahl, 1986). Research indicates that aerobic training can increase VO2 15-20 % with training (NCCP, 1990). The biochemical and metabolic adaptations that occur with endurance training are an increase in glycolytic enzymes (LDH, PDH, PFK), beta oxidation enzymes (acyl carnitine transferase), as well as increases in citrate synthetase in the TCA cycle. The primary benefit of these physiological changes are due to a greater use of fatty acids via beta oxidation for metabolic energy, thus reducing the demand for glycogen via glycolysis (Astrand and Rodahl, 1986). This in turn will provide a "glycogen sparring" effect, therefore prolonging the time it takes to fatigue during strenuous exercise. Applications of aerobic conditioning to judo involves a greater recovery from anaerobic work (via removal of metabolic by-products), in addition to a faster re-synthesis of phosphate (NCCP, 1990). This ability to recover quickly is crucial between matches, as that the number of matches performed during a tournament may range as high as 6 to 8 in one day.
Although aerobic power is an essential component of judo physiology, current literature indicates that the VO2 values for elite judo players are higher than normal, but not as high as endurance athletes. In comparison, endurance athletes like marathon runners and cross-country skiers typically demonstrate VO2 values of 70-80 ml kg-1 min-1. Taylor et al (1981) initially tested male Canadian players, and found mean VO2 values to be at 57.5 ml kg-1 min-1. Thomas et al (1989) examined VO2 values of Canadian male players, and compared these mean values to other nations. Canadian judoists were determined to have a mean value of 59.2 ml kg-1 min-1, with values ranging from 49.7-65.2 ml kg-1 min-1. This was similar to findings reported by Little (1991), who found that mean VO2 values for senior male judo athletes were 53.75 ml kg-1 min-1. When compared to Australian, Polish and Norwegian players, VO2 values were reported at 53.2, 59.0 and 58.5 ml kg-1 min-1, respectively. Findings by Mickiewicz et al (1987) revealed VO2 values of elite judo senior and junior males, and senior female Polish players to be 60.22, 60.23, and 49.90 ml kg-1 min-1, respectively. Callister et al (1991) determined U.S. male players to have a mean VO2 value of 55.6 ml kg-1 min-1, with females at 52.0 ml kg-1 min-1. In comparison, peak VO2 values for elite wrestlers range between 60 to 70 ml kg-1 min-1 (Cipriano, 1993). These values are higher than those cited by Horswill et al (1992), who reported peak VO2 to range form 51 to 62 ml kg-1 min-1, although, differences in peak values may be due to the format of assessment (ie. treadmill tests vs. arm and leg ergometry). It was reported that VO2 relative to body size was inversely related to weight division for both males and females respectively. This was identical to what Thomas et al (1989) found, in that aerobic power relative to body size tended to decrease with increases in weight divisions. This may be as a result of a greater proportion of body fat in the larger athletes.
Practical applications to the coach and sport scientist involve an understanding that aerobic performance and conditioning is not paramount in the physical development of world class judo athletes. Judo performance does require a good aerobic base or aerobic working capacity, and this can be developed through the nature of a typical competition practice. Judo practice would be a means of improving general conditioning, whereas running would be a means of enhancing general conditioning (Matsumoto et al, 1978). The very nature of judo training would involve athletes performing at or above 75 % of their individual heart rate maximums for a sustained period of 30-40 minutes during free practice sparring or "randori" (Kaneko et al, 1978). Perhaps the greatest benefit of aerobic training is the judo player's ability to operate at a high percent of their individual aerobic capacity. Research has indicated that trained aerobic individuals can work at 75-85% of their aerobic power before experiencing fatigue (NCCP, 1990). Callister et al (1991) reported that ventilatory thresholds of judo athletes were high, and that lactate levels following treadmill testing were low. This was most likely due to a reflection of the large quantity of high intensity training performed by elite judo players. This introduces the concept of anaerobic threshold training (AnT), or the point at which lactate production exceeds its removal during exercise (Astrand and Rodahl, 1986). Due to the high intensity nature of the sport, judo players repeatedly operate at or above the AnT throughout the course of training and competition. As a result, training should involve competitive situations, which would require the athlete to attain their individual AnT for a brief period. The corresponding physiological and biochemical adaptations would result in the athlete being able to perform at a higher percent of his VO2, and thus perform with more intensity during the match, in addition to being able to recover quicker between each high intensity match. The judo athlete should be tested regularly throughout the year to determine if the individual's VO2 score is at a comparable level to other world class judo athletes. Scores should be at a minimum of 55-60 ml kg-1 min-1, and if not, focus on the early stages of training should be to ensure that this score is acquired. Successful participation in judo competitions is technically mastery supported with above average endurance capacities (Little, 1991). This is typically done early in the athlete's career prior to world level competition and often is a result or by product of regular repeated practices over several years.