Karate training involves basic techniques, kata, and sparring. Basic techniques such as punching, kicking, blocking, and striking are practiced either in the stationary position (stationary basics) or with body movements in various formal stances (movement basics). The stationary basics and movement basics are very formal and systematic and combined with kata, which are set forms in pre-established sequences of defensive and offensive techniques and movements. Sparring is the execution of defensive and offensive techniques while one is freely moving against an opponent that is frequently associated with injuries. Instead, more often, sparring techniques are performed without an opponent (sparring TECH I) or against an opponent (sparring TECH II).
Traditional Japanese karate tournament consists of kata and sparring competitions. Because competition is the focal point of athletic training, a better understanding of the duration of each series of offensive and defensive techniques and the physiological responses during competition would be desirable to develop training programs for achieving optimal performance and avoiding injuries. For sport nutritionists, it is also important to know the energy expenditure (EE) during competition to advise athletes to consume adequate energy from a variety of foods to avoid injuries and problems that may arise due to nutritional deficiencies. Some studies reported only heart rate (HR) responses (15,17) or both oxygen uptake (V̇o2) and HR responses (16,25) of karate practitioners performing kata. However, only 1 study (20) reported HR responses, without measuring V̇o2 during a 3-minute bout of simulated karate sparring (3-minute bout of sparring). They estimated the percentage of maximum V̇o2 (%V̇o2max) of 3-minute bout of sparring from the HR obtained during the bout and HR-V̇o2 curve obtained from an incremental test to volitional exhaustion on a bicycle ergometer. However, these results need to be cautiously approached because higher HR responses were elicited for a given %V̇o2max during 5 types of karate exercises (stationary basics, movement basics, sparring TECH I, sparring TECH II, and kata) when compared with that for a cycle ergometer or treadmill (9,16,25).
The purpose of this study was to investigate the duration of each series of offensive and defensive techniques, V̇o2, HR and blood lactate responses, rate of perceived exertion (RPE), EE during a 2-minute bout of simulated karate sparring (2-minute bout of sparring) and 3-minute bouts of sparring.
Experimental Approach to the Problem
Because the duration of a sparring competition is usually 2 minutes for elimination matches and 3 minutes for semifinal and final matches, we performed 2- and 3-minute bouts of sparring in the same order. Each match was formally refereed and scored. To create a demanding competitive environment, each match was contested with an opponent of similar age, skills, training background, and body weight to simulate competition. At the start of a sparring match, the referee stood 2 meters from the center of the competition area. The contestants faced and stood 3 meters away from each other and at right angles to the referee. Each bout of sparring was started or stopped when the referee calls hajime, which means to start or yame, which means to stop. Attacks were limited to the following areas: head, face, neck, abdomen, chest, back, and side. In order to score, a technique must be applied to a scoring area. No contact was allowed with the head, face, and neck. Full contact with the abdomen was allowed. A score was awarded when a technique was performed according to the following criteria for a scoring area: good form, sporting attitude, vigorous application, good timing, and correct distance (23). During the match, the referee stayed a few meters away from the players to minimize any interference. However, every time 1 player scored, the referee stopped the fight and made the contestants moving back to the starting position. Then the referee awarded 3, 2, or 1 point according to the rules set by the World Karate Federation (23). This usually occurred within a few seconds to minimize any interference. Thus, the fight was stopped as many times as each contestant scored during the match, which is the official rules set by the World Karate Federation (23).
Because one purpose of this study was to estimate EE during 2- and 3-minute bouts of sparring, expired gas was collected using the Douglas bag for the entire period of each bout. Although the Douglas bag was affixed to the subjects' back with tape as much as possible, this could be inhibitory to performing some of the techniques. However, only straight punches are allowed, and other punches such as hook and upper punches are prohibited in the traditional Japanese karate sparring competitions. Also, most of kicks used in the competition are front and roundhouse kicks. These techniques could be performed with the Douglas bag much more easily than with a spinning back kick, which is also prohibited. Prior to the study, subjects were familiarized with how to spar while wearing the Douglas bag until they feel comfortable enough with this equipment to be able to spar. Each bout was videotaped, and the duration of each series of offensive and defensive techniques was estimated to the nearest 0.01 second from the videotape with a digital timer on the screen. However, in some cases, it was very difficult to determine when an offensive or defensive move began and ended to the nearest 0.01 second, so that the data were presented to the nearest 0.1 second. The duration of each series of techniques was defined as from the start to the end of total body movements when actual offensive and defensive techniques were performed so that feints and just reacting to an opponent's feint were not included. Two of the investigators have been official referees for the Federation of All Japan Karate Organizations. They observed the videotape and commented that these subjects competed quite well wearing the equipment.
Seven young men (age 18-20 years) and 6 boys (age 16-17 years) volunteered for this study. With the subjects, we formed 3 pairs of men and 3 pairs of boys to create a demanding competitive environment as stated previously. One man was excluded from the data because he fought against one of the investigators, who were middle age. So, the data included in each bout of sparring were the measurements of 12 subjects. They hold a black belt from the Federation of All Japan Karate Organizations, which unified major 4 styles (Shotokan, Wado, Gojyu, and Shito styles), and many other styles in Japan. The mean (± SD) age, height, body weight, and karate experience of the subjects were 18.0 ± 1.7 years, 167.6 ± 7.3 cm, 60.7 ± 7.3 kg, and 4.6 ± 3.5 years, respectively. Karate was the only form of training at least for 2 years for all subjects. The study protocol was approved by the Ethics Committee of the Nakamura Gakuen University, and informed consent was obtained from each subject. Informed consent was also obtained from a parent of the 6 boys.
Three to 7 days before the experiment started, each subject performed a incremental test to volitional exhaustion on a Woodway treadmill (Tokyo, Japan) using a modified Bruce protocol, which consisted of 3-minute work stages, starting with 1.7 miles·h−1 and the percentage of grade, after which the treadmill speed and grade were increased according to the protocol of Bruce (3). The test was conducted in air-conditioned facilities with the temperature set at 22°C. Ventilatory measurements were made by standard open-circuit calorimetry (Sensormedics Vmax, Yorba Linda, CA) with 30-second sampling intervals. The ventilatory threshold was estimated from the ventilatory equivalent and V̇o2 obtained during the treadmill test and was defined as the V̇o2, which occurred during the workload before ventilatory equivalent increased out of proportion to V̇o2, and a concomitant increase in the fraction of O2 in expired air was observed (22). The system was calibrated against a known mixture of gases before each experiment. The electrocardiogram (ECG), using a bipolar CM5 lead configuration, was monitored via radio telemetry (Nihon Koden, Tokyo, Japan). Exercise HR was recorded for 10 seconds during the final minute of each stage.
Alcohol intake and physical exercise were not allowed 1 day before each experiment. The participants reported to the laboratory at 7:00 am after an overnight fast. They were transported by a car to avoid unnecessary physical activity before each experiment. They finished eating breakfast by 7:30 am. The caloric content for the breakfast was approximately 42 kJ·kg−1 (10 kcal·kg−1) with 59%, 15%, and 26% energy derived from carbohydrate, protein, and fat, respectively. The subjects changed into their karate uniform after ECG surface electrodes were taped and sat quietly until 8:30 am, after which the resting measurements were taken. They sat quietly for 60 minutes after performing a 2-minute bout of sparring. By the end of this rest period, HR and V̇o2 returned to the resting values obtained prior to the 2-minute bout of sparring. Then they stretched again for 10 minutes and performed a 3-minute bout of sparring.
Expired gas was collected by the Douglas bag method for the entire period of each bout. The volume of gas was measured in a wet gas meter (Sinagawa Corp., Tokyo, Japan). Analyses for O2 and CO2 were performed on the system as described above. Blood lactate sample was taken in the sitting position in a chair before and immediately after the performance of each bout. Shortly after the 5 μl of blood was drawn from an earlobe, it was analyzed with the Lactate Pro Analyzer (Arkray, Tokyo, Japan). The Lactate Pro is supplied with a check strip to confirm that the analyzer is operating correctly and a calibration strip that provides a nonquantitative indication of instrument accuracy. The reported correlations between the Lactate Pro and the ABL 700 Series Acid-Base Analyzer YSI 2300 and Accusport were r = 0.98, r = 0.99, and r = 0.97, respectively (14). The ECG as described above was monitored with 4-channel radio telemetry (Fukuda Denshi, Tokyo, Japan). The subjects' HR was recorded for 10 seconds at the end of the 10-minute sitting rest and every minute thereafter. The percentage of maximum HR (%HRmax) and %V̇o2max were calculated by dividing exercise HR or exercise V̇o2 by HRmax or V̇o2max obtained from maximal treadmill exercise, respectively. RPE using Borg's scale from 6 to 20 was obtained immediately after the performance of each bout (1). The EE was calculated from V̇o2 and respiratory exchange ratio (RER) according to the following formula: EE = V̇o2 · (15.480 + 5.550 × RER) (5).
The SPSS statistical software 10.0J (Chicago, IL) was used to analyze the data. Descriptive statistics included mean and SD. Data were analyzed using repeated-measures analysis of variance and subsequently Tukey's test for post hoc analysis. Significance was defined as a p ≤ 0.05.
The mean V̇o2max, HRmax, RER, and %V̇o2max at ventilatory threshold measured by the treadmill run were 51.2 ± 4.3 ml·kg−1·min−1, 188.3 ± 2.4 beats·min−1, 1.10 ± 0.10, and 66.5 ± 7.0%, respectively.
The duration of performing the shortest offensive and/or defensive technique was 0.3 ± 0.1 second for both 2- and 3-minute bouts of sparring. The duration of longest series of performing offensive and/or defensive combination techniques during 2- and 3-minute bouts of sparring were 2.1 ± 1.0 and 1.8 ± 0.4 sec, respectively. The mean total times of performing offensive and defensive techniques during 2- and 3-minute bouts of sparring were 13.3 ± 3.3 and 19.4 ± 5.5 seconds, respectively.
The physiological responses, calculated values, and RPE of 2- and 3-minute bouts of sparring are shown in Table 1. The mean V̇o2, %V̇o2max, HR, %HRmax, RPE, and EE for a 3-minute bout of sparring were significantly higher than for a 2-minute bout. Blood lactate levels were elevated above the resting value, but there was no significant difference between the 2- and 3-minute bouts of sparring.
The relationship between %HRmax and %V̇o2max is shown in Figure 1. Higher HR responses were elicited during 2- and 3-minute bouts of sparring studied for given %V̇o2max than during the treadmill run.
The estimated %V̇o2max values during the 2- and 3-minute bouts of sparring from the HR obtained during these bouts and HR-%V̇o2 curve obtained from a maximal treadmill test were 77.3 ± 9.8% and 84.9 ± 8.1%, respectively. The corresponding %V̇o2max values calculated from V̇o2 measured during these bouts were 42.3 ± 10.0% and 47.8 ± 8.0%, respectively (Table 1), which were below the ventilatory threshold measured by treadmill running.
Some studies reported only HR responses (15,17) or both V̇o2 and HR responses (16,25) of karate practitioners performing kata. However, these studies are performed from a physical fitness point of view because karate training in general and karate kata in particular have been claimed to contribute to increasing general physical fitness and/or cardiovascular fitness (9). None of the studies have reported physiological responses of simulated karate competitions except 1 study (20), which reported HR responses, without measuring V̇o2, during a 3-minute bout of sparring. The authors estimated %V̇o2max during the bout from the HR obtained during the bout and HR-V̇o2 curve obtained from an incremental test to volitional exhaustion on a bicycle ergometer. The estimated mean %V̇o2max of a 3-minute bout of sparring was 72.5%. However, the results need to be cautiously approached because higher HR responses were elicited during the 5 types of karate exercises studied (stationary basics, movement basics, sparring TECH I, sparring TECH II, and kata) for given %V̇o2max than during the treadmill run (9,16,25). Similar results were obtained in the present study measuring both V̇o2 and HR during 2- and 3-minute bouts of sparring. To make a valid comparison between the study by Toyoshima et al. (20) and the present study, we estimated %V̇o2max during the 2- and 3-minute bouts of sparring from the HR obtained during these bouts and HR-V̇o2 curve obtained from a maximal treadmill test. The estimated mean %V̇o2max values of 2- and 3-minute bouts of sparring were 77.3 ± 9.8% and 84.9 ± 8.1%, respectively. The corresponding %V̇o2max values calculated from V̇o2 measured during 2- and 3-minute bouts of sparring were 42.3 ± 10.0% and 47.8 ± 8.0%, respectively. Thus, the estimated mean %V̇o2max of a 3-minute bout of sparring in the Toyoshima et al. study might be questionable. Shaw and Deutsch (16) suggested that the explanation for higher HR responses were elicited during karate exercises studied for given %V̇o2max than during the treadmill run could be due to the static nature of the arm movements involved in these activities, the arm movements themselves, or the combined effects of this type of exercise performed by the arms. Upper body exercises have been shown to induce a greater HR at a given V̇o2 than lower body exercises (7,19).
A review in a lay magazine (12) raises some arguments about training methods and nutritional strategies in karate. First, some karate instructors claim that practicing the stationary basics, movement basics, and kata exclusively will improve their sparring ability. However, sparring competitions are performed very rapidly and indeterminately and depend on an opponent's movements and skill level. The highly specialized nature of sparring requires that training develop the specific skills used in sparring. In a previous study from our laboratory (9), we reported physiological demands of 5 types of karate exercises in young men (age, 21 years; weight, 62.1 kg; height, 169.9 cm). The mean %V̇o2max values were 29.3 ± 7.3% for the stationary basics, 53.9 ± 9.2% for the movement basics, 54.8 ± 7.6% for sparring TECH I, 53.9 ± 9.2% for sparring TECH II, and 44.1 ± 3.7% for kata. Of these exercises, the stationary basics, movement basics, and kata are very formal and systematic unlike sparring. Because competition is the focal point of athletic training, any training program should mimic the competition and reflect the desired adaptation. The techniques and movements practiced in the sparring TECH I and sparring TECH II are very similar to sparring competitions. Also, the mean %V̇o2max values of sparring TECH I and sparring TECH II are above those of the 2- and 3-minute bouts of sparring obtained in the present study (42.3 ± 10.0% and 47.8 ± 8.0%, respectively), which might be necessary to overload a system to cause the body to respond and adapt. Thus, it is recommended that a sparring competitor practice longer duration of sparring TECH I and sparring TECH II than the stationary basics, movement basics, and kata.
The second argument is that some instructors claim that long distance running is important to increase cardiovascular endurance for sparring competitors and believe that strength training decreases flexibility and reduces the speed of techniques. The conditioning specialists may have to educate these instructors about how properly designed plyometric exercises and strength and ballistic training will not have this effect, but may increase punching and kicking speed, or power (13,21). Much of the power in various techniques, not only kicking techniques but also even hand techniques in karate, is generated through the hip rotation and related leg actions. To optimize power generated through the hip rotation, twisting crunches and other variations of rotary movements should be used, and also power exercises such as cleans and snatches should be used to increase power generated through the legs (8). Although resistance training does not appear to decrease flexibility, it has been suggested that flexibility training may be needed to increase the range of motion (6).
In comparison with top-level athletes in various sports, the mean V̇o2max (51.2 ± 4.3 mL·kg−1·min−1) of the subjects in the present study was much lower than long and middle distance runners and were similar to volleyball players and sprinters (11). Our findings indicate that the subjects in the present study were nonendurance athletes. In addition, it has been reported that lean body mass and strength are indicative of highly competitive karate players (2 world champions and 5 prize winners in international competitions in sparring were included in the subjects: age 21 years; weight, 66.3 kg; height, 172.9 cm), whose mean V̇o2max was also in the range of nonendurance athletes (10). The karate players may perform cardiovascular conditioning 3 days per week for short period of time (e.g., 20 minutes) to assist anaerobic recovery (6). However, because the high oxidative stress accompanying high-volume or high-intensity endurance training appears to negatively affect power development, they should limit high-intensity aerobic training (6).
In the present study, the duration of the longest series of performing offensive and/or defensive combination techniques during 2- and 3-minute bouts of sparring were 2.1 ± 1.0 and 1.8 ± 0.4 seconds, respectively, and the mean total time of performing offensive and defensive techniques during the 2- and 3-minute bouts of sparring were 13.3 ± 3.3 and 19.4 ± 5.5 seconds, respectively. Toyoshima et al. (20) reported similar results. Thus, the 2- and 3-minute bouts of sparring are characterized by short spells of high-intensity exercises, which are interrupted by less intense periods such as preparation for attack and/or defense and suspension by the referee and appear to be anaerobic. For rapid exercises lasting from a few seconds to approximately 1 minute, muscle depends mainly on immediate energy sources and glycolytic energy sources (2). Although blood lactate levels were moderate after performing 2- and 3-minute bouts of sparring (3.1 ± 1.0 and 3.4 ± 1.0 mmol·L−1, respectively), they were elevated above resting values. Thus, increasing the ability to buffer acid muscle and blood concentrations in order to demonstrate optimal strength and power during training and competition might be important. Performing resistance training with short rest intervals, traditional cardiovascular interval training, and/or punching and kicking as quickly as possible with short rest intervals are recommended to increase the buffering ability.
The third argument is that although some instructors recognize that nutritional strategies are an integral component of the overall goal of improving karate performance, it has been reported that highly competitive collegiate karate players may be at risk of suboptimal nutrient intake (18). In this study, daily EE was estimated from the basal metabolic rate, body surface area, and time and relative metabolic rate of various activities. The relative metabolic rates during karate exercises were calculated from the result of a previous study from our laboratory (9). We reported EE for 5 types of karate exercises in young men who hold a black belt. The mean values in kJ·kg·min−1 were 0.343 for the stationary basics, 0.632 for the movement basics, 0.649 for sparring TECH I, 0.640 for sparring TECH II, and 0.510 for kata. Physiological responses of 2- and 3-minute bouts of sparring were not measured in this study because these 5 types of karate exercises are typically practiced during a regular workout. However, karateists practice 2- and 3-minute bouts of sparring quite often before a tournament. They usually practice at least several rounds, so that it seems reasonable to use the EE obtained during 3-minute bout of sparring in the present study (0.500 kJ·kg·min−1) to estimate the EE for simulated karate sparring during a regular workout. Adding this EE value to the EE for 5 types of exercises, nutritionists can estimate the EE during the entire workout.
The common injuries in karate are sprains and bruises of the fingers, toes, and limbs. Most of these injuries could be prevented by hand, foot, and shin protectors. The significant injury sites are the head, neck, shoulder, and lower back (4,24). The strength training program in karate would include the neck, rotator cuff, and core stability and flexibility exercises. In addition to these exercises, the ballistic muscle contractions essential to various karate techniques necessitate development of agonist/antagonist muscle balance (8).
Because competition is the focal point of athletic training, any training program should mimic the competition and reflect the desired adaptation. Thus, it is recommended that a sparring competitor practice a longer duration of sparring TECH I or sparring TECH II than the stationary basics, movement basics, and kata. Because much of the power in various techniques in karate is generated through the hip rotation and related leg actions, twisting crunches and other variations of rotary movements and power exercises such as cleans and snatches should be included in the strength training. Although resistance training does not appear to decrease flexibility, flexibility training may be needed to enhance the range of motion. Performing resistance training with short rest intervals, traditional cardiovascular interval training, and punching and kicking as quickly as possible with short rest intervals are recommended to increase the ability to buffer acid muscle and blood concentrations. Although long-distance running is not recommended, the competitors may perform cardiovascular conditioning 3 days per week for short period of time to assist anaerobic recovery. It seems reasonable to use the EE obtained during 3-minute bout of sparring in the present study (0.500 kJ·kg·min−1) to estimate the EE for simulated karate sparring during a regular workout. Adding this EE value to the EE for 5 types of exercises, nutritionists can estimate the EE during the entire workout. To avoid or prevent athletic injuries, the strength training program in karate would include the neck, rotator cuff, and core stability and flexibility exercises. In addition to these exercises, the ballistic muscle contractions essential to various karate techniques necessitate development of agonist/antagonist muscle balance.
This study was supported by a grant from the Nakamura Gakuen University and the Beppu University.
1. Borg, GAV. Perceived exertion: a note on “history” and methods. Med Sci Sports
5: 90-93, 1973.
2. Brooks, GA, Fahey, TD, and White, TP. Exercise Physiology: Human Bioenergetics and Its Applications
(2nd ed.) Mountain View, CA: Mayfield Publishing Company; pp. 26-30, 39-48, 74-176, 1996.
3. Bruce, RA, Kusumi, F, and Hosmer, D. Maximal oxygen intake and nomographic assessment of functional aerobic impairment in cardiovascular disease. Am Heart J
85: 546-562, 1973.
4. Destombe, C, Lejeune, L, Guillodo, Y, Roundaut, A, Jousse, S, Devauchelle, V, and Saraux, A. Incidence and nature of karate injuries. Joint Bone Spine
73: 182-188, 2006.
5. Elia, M and Livesey, G. Theory and validity of indirect calorimetry during net lipid synthesis. Am J Clin Nutr
47: 591-607, 1988.
6. Fleck, SJ and Kraemer, WJ. Designing Resistance Training Programs (3rd ed.) Champaign, Ill: Human Kinetics; pp. 137, 146, 2004.
7. Gutin, B, Ang, KE, and Torrey, K. Cardiorespiratory and subjective responses to incremental and constant load ergometry with arms and legs. Arch Phys Med Rehabil
69: 510-513, 1988.
8. Hobusch, PT and McClellan, T. The karate roundhouse kick. Natl Strength Cond Assoc J
. 13: 18-21, 1991.
9. Imamura, H, Yoshimura, Y, Nishimura, S, Nakazawa, AT, Nishimura, C, and Shirota, T. Oxygen uptake, heart rate
, and blood lactate
responses during and following karate training. Med Sci Sports Exerc
31: 342-347, 1999.
10. Imamura, H, Yoshimura, Y, Uchida, K, Nishimura, S, and Nakazawa, AT. Maximal oxygen uptake
, body composition and strength of highly competitive and novice karate practitioners. Appl Hum Sci
17: 215-218, 1998.
11. Joussellin, E, Handschuh, R, Barrault, D, and Rieu, M. Maximal aerobic power of French top level competitors. J Sports Med Phys Fitness
24: 175-182, 1984.
12. Nishimura, S and Imamura, H. Practical sciences for winners [in Japanese]. Jpn Karatedo Fan
12: 91-97, 2003.
13. Olsen, PD and Hopkins, WG. The effect of attempted ballistic training on the force and speed of movements. J Strength Cond Res
17: 291-298, 2003.
14. Pyne, DB, Boston, T, and Martin, DT. Evaluation of the Lactate Pro blood lactate
analyser. Eur J Appl Physiol
82: 112-116, 2000.
15. Schmidt, RJ and Royer, FM. Telemetered heart rates recorded during karate katas: a case study. Res Q
44: 501-505, 1973.
16. Shaw, DK and Deutsch, DT. Heart rate
and oxygen uptake response to performance of karate kata. J Sports Med Phys Fitness
22: 461-468, 1982.
17. Stricevic, M, Okazaki, T, Tanner, AT, Mazzarella, N, and Merola, R. Cardiovascular response to the karate kata. Phys Sports Med
8: 57-67, 1980.
18. Teshima, K, Imamura, H, Yoshimura, Y, Nishimura, S, Miyamoto, N, Yamauchi, Y, Hori, H, Moriwaki, C, and Shirota, T. Nutrient intake of highly competitive male and female collegiate karate players. J Physiol Anthropol
21: 205-211, 2002.
19. Toner, MM, Glickman, EL, and McArdle, WD. Cardiovascular adjustments to exercise distributed between the upper and lower body. Med Sci Sports Exerc
22: 773-778, 1990.
20. Toyoshima, T, Inoshita, K, Ueda, D, Mori, K, and Nakano, S. Exercise intensity in a kumite bout estimated by oxygen intake, blood lactate
concentration and the speed of movement [in Japanese with English abstract]. Res J Budo (Martial Arts)
36: 31-38, 2003.
21. Voight, M and Klausen, K. Changes in muscle strength and speed of an unloaded movement after various training programmes. Eur J Appl Physiol Occup Physiol
60: 370-376, 1990.
22. Wasserman, K, Whipp, BJ, Koyal, SN, and Beever, WL. Anaerobic threshold and respiratory gas exchange during exercise. J Appl Physiol
35: 236-243, 1973.
23. World Karate Federation. Kata and kumite (sparring) competition rules. Version 5.3A Madrid; 2002.
24. Yoshimura, Y, Imamura, H, Okishima, K, and Nishimura, N. Injuries in collegiate karate athletes[in Japanese with English abstract]. Res J Budo (Martial Arts)
; 36: 39-44, 2003.
25. Zehr, EP and Sale, DG. Oxygen uptake, heart rate
and blood lactate
responses to the chito-ryu seisan kata in skilled karate practitioners. Int J Sports Med
14: 269-274, 1993.