Eur J Appl Physiol (2009) 107:603–610 DOI 10.1007/s00421-009-1154-y
ORIGINAL ARTICLE
Energetics of karate (kata and kumite techniques) in top-level athletes Christian Doria Æ Arsenio Veicsteinas Æ Eloisa Limonta Æ Martina A. Maggioni Æ Pierluigi Aschieri Æ Fabrizio Eusebi Æ Giorgio Fano` Æ Tiziana Pietrangelo
Accepted: 29 July 2009 / Published online: 27 August 2009 Ó Springer-Verlag 2009
Abstract Breath-by-breath O2 uptake (V_O2 , L min-1) and blood lactate concentration were measured before, during exercise, and recovery in six kata and six kumite karate Word Champions performing a simulated competition. V_O2max ; maximal anaerobic alactic, and lactic power were also assessed. The total energy cost (VO2TOT ; mL kg-1 above resting) of each simulated competition was calculated and subdivided into aerobic, lactic, and alactic fractions. Results showed that (a) no differences between kata
C. Doria G. Fano` T. Pietrangelo (&) Department of Basic and Applied Medical Sciences, University ‘‘G.d’Annunzio’’ Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy e-mail:
[email protected] G. Fano` e-mail:
[email protected] C. Doria E. Limonta M. A. Maggioni F. Eusebi G. Fano` T. Pietrangelo Interuniversity Institute of Myology (IIM), University ‘‘G.d’Annunzio’’ Chieti-Pescara, Chieti, Italy A. Veicsteinas E. Limonta M. A. Maggioni Department of Sport Sciences, Nutrition and Health, University of Milan, Via Colombo 71, 20133 Milan, Italy P. Aschieri Federazione Italiana Judo Lotta Karate ed Arti Marziali (FIJLKAM), Viale Sandolini 79, 00122 Rome, Italy F. Eusebi Department of Human Physiology and Pharmacology, University ‘‘La Sapienza’’, P.le A. Moro 5, 00185 Rome, Italy A. Veicsteinas Center of Sport Medicine, Don Gnocchi Foundation, Via Capecelatro 66, 20148 Milan, Italy
and kumite groups in V_O2max ; height of vertical jump, and Wingate test were found; (b) VO2TOT were 87.8 ± 6.6 and 82.3 ± 12.3 mL kg-1 in kata male and female with a performance time of 138 ± 4 and 158 ± 14 s, respectively; 189.0 ± 14.6 mL kg-1 in kumite male and 155.8 ± 38.4 mL kg-1 in kumite female with a predetermined performance time of 240 ± 0 and 180 ± 0 s, respectively; (c) the metabolic power was significantly higher in kumite than in kata athletes (p B 0.05 in both gender); (d) aerobic and anaerobic alactic sources, in percentage of the total, were significantly different between gender and disciplines (p \ 0.05), while the lactic source was similar; (e) HR ranged between 174 and 187 b min-1 during simulated competition. In conclusion, kumite appears to require a much higher metabolic power than kata, being the energy source with the aerobic contribution predominant. Keywords Oxygen consumption Energy cost Energy sources Blood lactate Kumite Kata Karate Maximal aerobic and anaerobic power
Introduction Karate is a martial art developed in the Ryukyu Islands (Japan) from indigenous fighting methods and Chinese kenpo¯. Athletes use almost all muscles during training and competition, but the two forms of the sport (kumite and kata) differ significantly with regards to style and corresponding muscle use. Kata consists of a predetermined series of movements that are performed with explosive swiftness against imaginary opponents, whereas kumite involves noncontact fighting.
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Kata Kata, which means ‘‘form,’’ incorporates techniques from various schools of martial art, and athletes move in several directions in space. It is not regarded as a symbolic battle to be performed alone, but rather as a battle against one or more invisible opponents. Various schools incorporate different numbers of kata techniques, and refer to them by distinct names. The basic elements of proper kata technique include kime (a short isometric muscle contraction performed when a technique is concluded), expressiveness, and rhythm. During competitions, the athletes perform fixed kata styles (Shitei) that have a different duration for every kata performed. Athletes that reach the final must perform one fixed kata styles (Shitei) and one freestyle kata (Tokui) that must have minimum and maximum duration of 60 and 80 s and an athlete is penalized for every second over or under this limit, according to the World Karate Federation (WKF)-based system styles. Kumite The kumite athletes perform ritualistic rather than actual fights. Although these competitions involve noncontact fighting and symbolic techniques, the athletes must demonstrate the potential force of their movements and execute them as if they were real, using control to stop the movements so as not to inflict damage to the opponent. Kumite competitions last 3 min for athletes in the senior male division, and 2 min for athletes in the senior female cadet and junior divisions. In the event of a tie, the competition is extended for an additional minute and the first athlete who performs a valid technique wins. If the tie persists, a panel of judges determines the winner. A previous study (Francescato et al. 1995) analyzed the total energy costs and energy sources in eight 23-year-old male kata practitioners, performing Pinan ni dan kata of the wado style. The metabolic power (i.e., the energy requirement from the sum of oxygen consumption and the oxygen equivalent of lactate production) of these athletes was high and correlated with the duration of their activity. The main energy source was the anaerobic alactic metabolism, yielding 46–90% of total energy during competitions lasting 80 and 10 s, respectively. Another study considered metabolic costs in ten nationally and internationally ranked males performing kumite karateka in fights lasting 267 ± 61 s during a championship. This study measured the aerobic, anaerobic alactic, and lactic energy sources, and demonstrated that aerobic metabolism was the predominant source of energy, but with a significant contribution from the anaerobic alactic metabolism (Beneke et al. 2004). To date, no studies have compared the total energy cost and the energy sources between kata and kumite athletes
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(male vs. female of kata, male vs. female of kumite, kata male vs. kumite male and kata female vs. kumite female). Thus, the aim of the study was to evaluate the energy cost and the energy sources of a well-selected group of Italian top-level kata and kumite athletes, including world champions, together with their physiological characteristic such as the maximal aerobic and anaerobic powers and the explosive strength with the purpose to provide support for athlete training.
Methods Anthropometric characteristics Twelve Italian internationally ranked male (M) and female (F) karate athletes participated in this study. The kata athletes were gold medalists in the Senior category, except for two females in the Junior category, and the kumite athletes were gold, silver, and bronze medalists in the Senior category, except for two females in the Junior category, all competing at the European and World Championships of 2006–2007. The physical characteristics of the athletes are shown in Table 1. All tests were performed at a national gathering of karate athletes and all subjects had participated in the European Championships 2 weeks before the study. Before each test, athletes were informed of the reasons for the study as well as the risks involved in the test. All subjects provided written informed consent before participation. The study conformed to the standards set by the Declaration of Helsinki and was approved by the local Ethics Committee. Laboratory test procedures Before each test, the athletes were familiarized with the instrumentations and the procedures and when required, a standardized warm-up was administered. Aerobic power Maximum oxygen consumption (V_O2max ; mL kg-1 min-1) and heart rate (HR, b min-1) were measured during a conventional graded-cycle ergometer test, using the portable breath-by-breath oxygen uptake telemetric system K4b2 (COSMED, Rome, Italy) (Hausswirth et al. 1997). The device was calibrated before each test according to the manufacturer’s instructions. Athletes performed a 5-min warm-up at 50 W, followed by 2 min exercise at 50 W for F and 75 W for M. Then, the work load was increased by 25 W every 2 min until volitional exhaustion. Few athletes (2 for each style), not familiar with the cycle ergometer
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Table 1 Anthropometric characteristics and laboratory data of elite karate athletes
M male, F female, n number of athletes, V_O2max maximal oxygen uptake during incremental cycle ergometer test, SJ squat jump, CMJ counter movement jump, PP peak power, MP minimum power, AP average power, FI fatigue index (Wingate test) * p \ 0.05 between genders in the same discipline
Kata
Kumite
M (n = 3) (m ± SD)
F (n = 3) (m ± SD)
M (n = 3) (m ± SD)
F (n = 3) (m ± SD)
Age (years)
30.7 ± 2.1
19.3 ± 0.6
24.0 ± 4.6
21.3 ± 1.5
Body weight (kg)
78.5 ± 3.5
52.5 ± 7.5*
76.3 ± 3.2
55.8 ± 2.8*
Height (m) V_O2max (mL min-1)
1.76 ± 0.03
1.59 ± 0.04
1.81 ± 0.05
1.59 ± 0.03 2,395 ± 169*
3,739 ± 186
2,222 ± 293*
3,696 ± 430
V_O2max (mL kg-1 min-1)
47.8 ± 4.4
42.4 ± 1.0
48.5 ± 6.0
42.9 ± 1.6
SJ (cm)
38.9 ± 1.1
36.9 ± 1.5
40.1 ± 3.2
37.0 ± 1.1
CMJ (cm)
42.7 ± 4.4
38.3 ± 1.0
42.8 ± 4.2
39.2 ± 2.4
PP (W kg-1)
9.7 ± 0.6*
7.7 ± 0.5
9.6 ± 1.1*
7.8 ± 0.6
MP (W kg-1)
5.7 ± 0.2
5.3 ± 0.5
6.0 ± 0.3
5.0 ± 0.3
7.8 ± 0.2* 40.8 ± 4.2
6.5 ± 0.3 30.8 ± 8.3
7.9 ± 0.6* 36.9 ± 5.7
6.6 ± 0.4 36.5 ± 1.4
-1
AP (W kg ) FI (%)
(personal communication of the coach), interrupted the test for pain and exhaustion of the lower limb muscles when the heart rate was lower than the age predicted value (Tanaka et al. 2001). For these subjects, the V_O2max was extrapolated to the predicted HRmax. Maximal anaerobic alactic power On a separate day, the athletes performed three maximal squat jumps (SJs) and three maximal counter-movement jumps (CMJs) of the Bosco test using an Ergojump contact mat (MAGICA, Rome, Italy), which allows the measurement of the flight time. The highest of the three values of each jump was taken and the maximal anaerobic (alactic) power was assessed (Bosco et al. 1983).
(c) the fatigue index (FI), i.e., the amount of the decline in power during the task. FI is calculated as the percentage of the differences between PP and MP setting PP to 100% (Inbar et al. 1996). Blood lactate concentration was determined (Pyne et al. 2000) using a portable blood lactate analyzer (Lactate Pro LT-1710; Arkray, Kyoto, Japan). One drop of blood was obtained from a fingertip before the WAnT session and every 2 min thereafter for 10 min. The peak lactate concentration was assumed to be the highest value reached after the WAnT. Simulated competition study The athletes were grouped according to their specializations and asked to simulate a competitive event.
Maximal anaerobic lactic power Kata The maximal anaerobic power and the total anaerobic capacity were determined by the Wingate Anaerobic Test (WAnT) (Bar-Or 1987), carried out using a mechanically braked cycle ergometer (Ergomedic 894 E; Monark, Varberg, Sweden). Following a standardized warm-up of 5 min at medium intensity cycling, the athletes were instructed to pedal as fast as possible. Resistance corresponding to 7.5% of body weight was applied after an unloaded acceleration phase that lasted about 3 s. Athletes were verbally encouraged to maintain the highest possible pedaling rate throughout the 30-s test. After the test, athletes remained in a sitting position for 30 min. The test scores were: (a) the peak power (PP) and the minimum power (MP) output, respectively, the highest and the lowest mechanical power observed as a mean of 5-s period exercise interval; (b) the average power (AP), corresponding to the mean power output throughout the six 5-s periods; and
The male kata athletes performed the fixed kata styles (Shitei) termed Unsu of the Shotokan style, whereas the female kata athletes performed the fixed kata styles (Shitei) named Hanan of the Shito-Ryu style. The corresponding duration required by the international rules is 140 and 160 s for M and F, respectively. Kumite The kumite athletes performed simulated fights against opponents, consisting of techniques of attack and defense, lasting without interruption 240 s for M and 180 s for F. These times represented the longest durations of actual kumite world championship competitions. Before each simulated competition, all athletes performed individual warm-up exercises equal to those
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performed in occasion of current competitive event and consisting of approximately 5 min of running, 10 min of stretching, and 10 min of sports-specific movements. After the simulated competition, the athletes remained in sitting position for 30 min. Oxygen consumption, as in previous tests, was continuously measured using the same portable breath-by-breath telemetric system at rest, during warm-up, competition, and recovery. Blood lactate levels were measured at rest; immediately before the warm-up exercise; at the end of the simulated competition; and at the 5th, 7th, and 9th minute of recovery in a sitting position. The total energy cost (VO2TOT ) of each task was calculated and then divided into aerobic, lactic, and alactic fractions on the basis of (a) aerobic energy obtained from the amounts of VO2 above rest during simulated competition (VO2 ); (b) an energy equivalent of 3 mL O2 kg-1 of body weight for every 1 mmol L-1 of blood lactate accumulation (di Prampero 1981) to measure activity of the anaerobic lactic system (VO2La ); and (c) the amount of O2 above resting consumed in recovery that was required to approximately reconstitute the high-energy phosphates used during the exercise (VO2PCr ). In particular, the energy contribution of the anaerobic alactic system VO2PCr was determined by measuring the fast component of excess postexercise oxygen consumption using a modified double exponential decay equation (Beneke et al. 2002). The amplitude and the time constants of the fast component were derived from the best fit of V_O2 recovery curve using a nonlinear least squares fitting procedure (Origin, Microcal, Northampton, MA, USA). Moreover, the replenishment of body O2 stores (lung and venous blood) was subtracted from the time integral of the V_O2 fast component (Astrand and Rodahl 1977). Dividing the VO2TOT for the duration of the performance in minutes, the metabolic power (V_O2MP ) was calculated. In addition, the metabolic power (WTOT) in kW and the percentages of aerobic (WVO2 ), anaerobic alactic (WPCr), and lactic (WLa) sources were also calculated in relation to the total metabolic work (WTOT). A caloric equivalent of 21.131 J mL-1 was used. Statistical analysis Results are reported as mean ± standard deviation (m ± SD). Statistical comparisons were calculated using the nonparametric Kruskall–Wallis Test followed by the Mann–Whitney Test on each pair of groups. Statistical significance was set at p \ 0.05. All the statistical analyses have been performed with the GraphPad Prism Software, version 5 (GraphPad Software, La Jolla, CA, USA).
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Results Anthropometric characteristics and laboratory study The anthropometric and physiological characteristics of the athletes are listed in Table 1. The V_O2max were measured by graded-cycle ergometer test and expressed in mL min-1 and mL kg-1 min-1. Significant differences (p \ 0.05) were found between M and F of both kata and kumite, but no differences were seen comparing the same gender in the different discipline. Considering V_O2max referred to the body weight, no differences were found. The corresponding maximal HR values (b min-1) were: 187 ± 2 and 194 ± 2 for M and F kata athletes, and 191 ± 4 and 193 ± 2 for M and F kumite athletes, respectively. The mean values of SJ and CMJ were similar in all athletes (Table 1). Wingate test showed that PP and AP were significantly lower in F than in M athletes in both kata and kumite (p \ 0.05). The FI was not significantly different between disciplines (Table 1). Peak blood lactate concentration measured after the WAnT were (mmol L-1) 14.6 ± 1.9 and 13.3 ± 3.0 for M and F kata athletes, and 12.1 ± 1.8 and 12.4 ± 2.2 for M and F kumite athletes, respectively. No significant differences in blood lactate accumulation between kata and kumite athletes were found. Energy cost of simulated karate competition The durations of the simulated kata performances were 138 ± 4 and 158 ± 14 s in M and F, respectively, and the corresponding durations in kumite were 240 and 180 s for M and F, respectively. Figure 1 depicts an example of breath-by-breath oxygen uptake of a M and a F kumite athlete performing a simulated competition including warm up and recovery. After few minutes of resting V_O2 values of about 0.3 L min-1, the O2 consumption oscillated with time according to the warming up procedure used by each individual athlete, characterized by personalized tasks and short recovery intervals. During the actual competition phase (exercise in the figure) V_O2 increased sharply reaching an almost steady state value after about 1 min, followed by an exponential decline in recovery. Similar pattern of V_O2 changes were observed in all subjects, irrespective of gender and type of performance. During recovery, the time constants of the fast component of oxygen uptake were 40.6 ± 4.9 and 46.3 ± 3.1 s for M and F kata athletes (p [ 0.05) and 47.3 ± 0.6 and 31.5 ± 9.5 s for M and F kumite athletes (p \ 0.05), respectively. These time constants were significantly different between M of kata with respect to M of kumite and between F of kata with respect to F of kumite.
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Fig. 1 Oxygen uptake breath-by-breath in kumite simulated competition. Representative plots of oxygen uptake (breath-by-breath) by male (a) and female (b) kumite athletes. After 5 min sitting (rest in the figure), the athletes performed typical precompetition warm-up exercises and then were engaged in 4-min (male) and 3-min (female) simulated competition (exercise in the figure; see ‘‘Methods’’ for more details)
The corresponding VO2PCr were 1,895 ± 438 and 1,192 ± 181 mL for M and F kata athletes and 2,047 ± 520 and 1,575 ± 363 mL for M and F kumite athletes (p \ 0.05), respectively. The net blood lactate concentrations (highest postcompetition blood lactate minus resting) expressed in mmol L-1 were 6.5 ± 1.3 for M and 3.9 ± 1.7 for F kata, and 7.5 ± 2.4 and 10.6 ± 4.8 for M and F kumite athletes, respectively. From the V_O2 of Fig. 1, the variables given in Table 2 were calculated. The same table includes the average duration of the competition and the corresponding maximal heart rate reached. In Table 2, the mean values ± SD of all variables required to calculate the energy sources and the metabolic power are reported. Data are given both in oxygen equivalent and in kJ. In kata, similar values of VO2 ; VO2PCr ; VO2La ; and VO2TOT were found in M and F when expressed as mL kg-1. When VO2TOT was normalized to performance time in minutes, the resulting V_O2MP was statistically higher in M and F kumite athletes with respect to kata athletes (p \ 0.05). In kumite, again no significant differences in normalized values were found between genders, even when the much longer time of performance of M is taken into account. The VO2 ; VO2PCr ; and VO2La expressed as a fraction of VO2TOT are shown in Fig. 2.
607
A comparison between kata and kumite disciplines (Fig. 2) revealed that the aerobic percentage significantly differed between M and F kumite athletes and between M athletes of kata and kumite (p \ 0.05). The anaerobic lactic sources were not significantly different. The anaerobic alactic sources differed in M and F athletes of each discipline (p \ 0.05). The aerobic contribution was statistically higher (p \ 0.05) in M kumite (74 ± 1%) vs. kata (50 ± 6%). Vice versa in both M and F, the alactic contribution was higher (p \ 0.05) in kata (28 ± 6% in M; 29 ± 5% in F) than in kumite (14 ± 3% in M and 18 ± 1% in F). The VO2TOT (given in Table 2), normalized to the time of competition and expressed as V_O2MP in mL kg-1 min-1 (also given in Table 2), was compared to the maximum oxygen uptake above resting. The corresponding ratio is given in Fig. 3. The metabolic power required to complete the simulated competition was significantly higher in both M and F kumite athletes with respect to kata athletes (p \ 0.05). Compared to the HRmax measured during the cycle ergometer tests, the maximal HR of the simulated competition were 94 ± 7 and 90 ± 3% in M and F, respectively, in kata; and 92 ± 2 and 97 ± 6% (M and F, respectively) in kumite.
Discussion To our knowledge, physiological differences in energy production between internationally ranked male and female kata and kumite athletes have not previously been evaluated. Maximal velocity and explosive strength are the most important muscular factors required for karate performance. These parameters correlate with the competitive level of the athletes. Previous studies have shown that the explosive strength of international karate athletes is about 14% higher than that of national athletes (Ravier et al. 2004). We examined differences in explosive strength between the two karate disciplines. Vertical jump values (SJ and CMJ tests) revealed that explosive strength was not different in kata and kumite athletes. The lack of differences between male and female may be due to the low number of athletes examined. Unfortunately, we could not find additional athletes of such top levels, at least in the Italian team. The Wingate test has been used to assess lower limb muscle power in martial arts, particularly in judo exponents (Sbriccoli et al. 2007). The use of the lower limbs differs in kata and kumite competitions, and a sports-specific test does not exist. To our knowledge, this is the first attempt to characterize the muscle power of elite kata and kumite athletes using the Wingate test. The PP, reflecting the highest energy-generating capacity of the high-energy
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Table 2 Metabolic responses of kata and kumite athletes during simulated competitions Kata
Kumite
M (n = 3) (m ± SD)
F (n = 3) (m ± SD)
M (n = 3) (m ± SD)
F (n = 3) (m ± SD)
Time (s)
138.0 ± 4.0
158.0 ± 14.0
240.0
180.0
HRmax (b min-1)
176.0 ± 12.0
174.0 ± 4.0
175.0 ± 5.0
187.0 ± 12.0
VO2 (mL kg-1)
43.9 ± 3.9
47.9 ± 8.5#
139.8 ± 12.0#
95.8 ± 18.5*
-1
VO2PCr (mL kg )
24.3 ± 6.1
22.7 ± 1.1
26.7 ± 5.6
28.1 ± 5.6
VO2La (mL kg-1)
19.6 ± 3.3
11.6 ± 5.1
22.5 ± 7.1
31.8 ± 14.3
VO2TOT (mL kg-1) V_O2MP (mL kg-1 min-1)
87.8 ± 6.6# 38.2 ± 3.8#
82.3 ± 12.3# 31.4 ± 6.0#
189.0 ± 14.6 47.2 ± 3.7
155.8 ± 38.4* 51.9 ± 12.8
WVO2 (kJ)
72.9 ± 7.6#
54.0 ± 16.1#
225.5 ± 20.4
113.4 ± 26.2*
WPCr (kJ)
40.0 ± 9.3
25.2 ± 3.8
43.3 ± 11.0
33.3 ± 7.7
32.4 ± 4.1
WLa (kJ) WTOT (kJ) WTOT (kW)
16.2 ± 7.2
36.1 ± 10.4
37.8 ± 18.2
145.3 ± 4.5#
92.3 ± 24.5*
304.8 ± 25.5#
184.6 ± 52.0*
1.05 ± 0.06
0.59 ± 0.19*
1.27 ± 0.11#
1.03 ± 0.29#
Time in seconds, duration of the simulated competition, HRmax heart rate calculated as the mean values of the last 20 s of simulated competitions, VO2 oxygen consumed above resting during the simulated competition, VO2PCr VO2 equivalent above resting of the fast component of the postcompetition VO2 , VO2La VO2 equivalent of lactate accumulation during exercise, VO2TOT total energy cost (VO2 þ VO2PCr þ VO2La ), V_O2MP metabolic power, oxygen consumed per minute of simulated competition, WVO2 aerobic energy corresponding to VO2 , WPCr anaerobic alactic energy corresponding to VO2PCr , WLa anaerobic lactic energy corresponding to VO2La , WTOT total metabolic work (WVO2 ? WPCr ? WLa), WTOT metabolic power. Only WTOT and VO2MP can be normalized in all the experimental groups and then compared by a statistical procedure (see ‘‘Methods’’ for more details) * p \ 0.05 between genders in the same discipline,
p \ 0.05 between disciplines in the same gender
#
*
40
#
·
Anaerobic alactic
#
# 60
1.0 0.5
Aerobic
20
F
M
M
F
0 kata
kumite
Fig. 2 Aerobic, anaerobic alactic, and lactic energy sources in kata and kumite athletes. Values are m ± SD; n = 3. Relative energy contributions of aerobic (gray), anaerobic alactic (light gray), and lactic sources (white) during kata and kumite simulated competitions. The height of each histogram represents the total oxygen cost (VO2TOT of Table 2) set = 100%. (M male, F female) (*p \ 0.05 between genders in the same discipline, #p \ 0.05 between disciplines)
phosphates, and the AP, reflecting the glycolytic capacity, were found significantly higher in males than in females in both disciplines, thus showing that females use less power and place greater emphasis on harmonious movements, whereas male athletes use higher force to perform explosive movements. The average power is a measure of the average mechanical power of the 30-s test, which, in turn, reflects the capacity of leg muscles to perform extremely
#
1.5
·
80
123
2.0
Anaerobic lactic
VO2MP / VO2max
Energy sources (%)
100
#
F
M 0.0
kata
M
F
kumite
Fig. 3 Metabolic power to maximal aerobic power ratio of kata and kumite. Values are m ± SD, n = 3. The metabolic power (V_O2MP ) expressed in relation to the maximal aerobic power (V_O2max above resting) is shown in male (M) and female (F) kata and kumite athletes. # p \ 0.05 between disciplines
powerful movements that require both aerobic and anaerobic metabolic sources (Beneke et al. 2002). The average power value was lower in females than in males, as previously reported (Gratas-Delamarche et al. 1994; Sands et al. 2004). Moreover, the FI, i.e., the total capacity to produce energy via the immediate and the short-term energy systems, resulted similar in kata and kumite athletes. The V_O2max per unit body weight was determined by the graded-cycle ergometer test and in four athletes (two for
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each discipline) extrapolated to the predicted HRmax (see ‘‘Methods’’). The collected data altogether analyzed were similar both in the two genders and in the different disciplines (Table 1). When data presented here are compared with those of male karateka measured by Francescato et al. (1995), a slightly higher aerobic power has been found in our athletes, probably as a consequence of the very high level of athletes enrolled in our study. In contrast, the V_O2max values reported by Ravier et al. (2006) are higher than ours, presumably in part due to the different methodology used to determine V_O2max . In this study, the cycle ergometer was used, which is known to underestimate of about 8–10% the corresponding value assessed by treadmill (Astrand and Rodahl 1977). In addition, the task was interrupted at relatively low power values (from 150 to 250 W at the most), for local fatigue or pain in the lower leg muscles. Moreover, Ravier et al. also showed, after a supramaximal treadmill test, that lactate levels in male karate athletes were significantly higher in national than in international athletes. Their study concluded that the higher concentration of lactate after exhaustive exercise might reflect a lower level of anaerobic energy supply or a more efficient removal in international athletes. The athletes of our study accumulated significantly less lactate after the WAnT test compared with the athletes of Ravier et al. (approximately 13 mM, in our athletes vs. about 18 mM, without any differences between genders and/or disciplines). Considering that the tests carried out were different, it is possible that muscle performance of our athletes required a lower anaerobic energy than that used by the athletes tested by Ravier. The aerobic energy source was predominant in our study (50–74% of the total), with some difference among genders and disciplines, while the lactic source represents the lowest percentages (12–22%) of energy used, and the alactic intermediate (14–28%). Kata used twice as much alactic source than kumite athletes. However, kumite performances were more demanding of aerobic energy during simulated competitions. In a study on energy cost and sources in karate athletes, Francescato et al. (1995) examined male athletes performing wado-style kata of increasing duration (approximately 10–80 s). Their study demonstrated that after 80 s of activity, 41% of the total energy used was aerobic, 13% was lactic, and 46% was alactic. The performances in their study were approximately half as long as those of our simulated kata performances. Although style differences must be considered, in an attempt to compare the data of Francescato et al. with ours in male kata athletes, it appears that similar contribution of aerobic source was found, while the longer duration of the performances (about 140 s) of our male kata athletes increased presumably the lactic source.
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Comparing the two disciplines in males, a higher aerobic source in kumite (74%) than in kata (50%) was found, while in kata higher anaerobic sources were observed. The difference is presumably due to different muscular recruitment and control required in the two disciplines and by the time duration of the performances (240 s in kumite vs. 138 s in kata). In female athletes, probably due to higher intensity of the explosive swiftness movements, a difference only in the anaerobic alactic sources between kata and kumite (about 30 vs. 14%) was seen. When compared to the maximal aerobic power measured on the cycle ergometer, the metabolic power, i.e., the total (aerobic and anaerobic) energy expenditure rate of kumite and kata athletes were well above 1 and slightly below 1, respectively, in both genders (Fig. 3). This findings are consistent with the different contribution of the energy sources and duration of the performances and it is conceivably to assume that they are mainly due to the both much higher speed and force of each single movement and to the higher contribution of static contraction required to keep the body in position when upper limbs movements are performed.
Conclusion World champions of kata and kumite have approximately the same maximal aerobic and anaerobic powers per unit body weight during conventional laboratory tests. In the simulated competition, the metabolic power of kumite is about 1.5 times V_O2max . The total energy cost is paid approximately by aerobic component (70%), with utilization of alactic energy stores (20%) and lactic acid production (10%). In kata, the metabolic power is lower than V_O2max and the aerobic and anaerobic (alactic and lactic) sources are almost equally divided. It is important to note that the main purpose of this work is not to provide precise data of the energy cost and sources involved in karate’s discipline, as the data presented are from a very small sample of elite athletes not representative for number and quality of performance of the entire population practicing this sport. The goal of this experimental study was to associate a metabolic evaluation, assessed with standard procedures, to the ability to achieve the very high performance level that the athletes we tested have shown to possess. Thus, our results can reasonably be proposed as a ‘‘table reference’’ for the preparation of the athletes of a specific discipline not deeply studied as karate. Acknowledgments We thank Dr. Pierpaolo Iodice and Dr. Fabrizio Schiazza for technical suggestions that assisted in the performance of the Wingate test, and Dr. Giampiero Merati and Dr. Luca Agnello for discussing the data. This research was supported by grants of G.F. and A.V.
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610 Conflict of interest statement no conflict of interest.
Eur J Appl Physiol (2009) 107:603–610 The authors declare that they have
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