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J SPORTS MED PHYS FITNESS 2012;52:237-44

Physiological response of high-level female judokas measured through laboratory and field tests. Retesting the validity of the Santos test

IN C ER O V P A Y R M IG E H DI T C ® A

L. SANTOS 1, V. GONZÁLEZ 1, M. ISCAR 2, J. I. BRIME J. FERNÁNDEZ-RÍO 4, B. RODRÍGUEZ 2, M. Á. MONTOLIU

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Aim. The aim of the study was to measure the physiological demands of a group of high-level female judokas through laboratory tests and field tests (Tatami) and to retest the validity of the Santos test on a different population. Methods. Eight high-level female judokas participated in the study. Heart rate (HR), maximal oxygen consumption (VO2 max), blood lactate, anaerobic threshold, and ratings of perceived exertion (RPE) were measured using laboratory and field tests that shared common characteristics. Results. The mean (±SD) values obtained in the laboratory tests were HRmax 198.3 (4.1) beats.min-1, VO2 max: 40.9 (7.7) mL.kg-1.min-1, lactate max 9.1 (1.4) mmol.L-1, HR at the anaerobic threshold 171.5 (4.8) beats.min-1, lactate threshold 3.8 (0.4) mmol.L-1, and RPE: 17 (1.1). The mean (±SD) values obtained in the field test were HRmax 199.0 (5.0) beats.min-1, VO2 max: 44.8 (7.3) mL.kg-1.min-1, lactate max: 11.8 (1.5) mmol.l-1, HR at the anaerobic threshold 170.5 (3.2) beats. min-1, lactate threshold: 3.8 (0.1) mmol.L-1, and RPE: 18 (1.4) points. There were no significant differences between the data obtained on both tests in any of the parameters, except for the lactate maximum and VO2 max. Conclusion. The Santos test is a helpful instrument for judo training in female athletes. Coaches could use it to design specific training protocols that could help to improve their performance in competition. Key words: Martial arts - Energy metabolism - Physical endurance.

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udo (in Japanese “the gente way”) is a hand-tohand martial art developed in the second half of the XIX century by Jigoro Kano in Japan. It soon became a popular type of combat, self-defence activity, and sport. In 1956, the first judo World Championship was held in Tokyo, and in 1964, it became an

Corresponding author: L. Santos Rodríguez, Calvo Sotelo n. 17 4º Izq, 33007 Oviedo, Spain. E-mail: [email protected]

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1Medical

Service of the Community of Cabo Peñas, Luanco, Spain 2Exercise Physiology Unit Hospital Universitario Central de Asturias, Oviedo, Spain 3Department of Functional Biology University of Oviedo, Oviedo, Spain 4Department of Educational Sciences University of Oviedo, Oviedo, Spain

Olympic sport. Judo regulations promote offensive actions and penalize passiveness. The referee is allowed to stop the combat and sanction those behaviors. One of the most significant rules is the “Golden Score”. If the scores of both competitors are identical at the end of the match, the contest is solved using this rule. This is a sudden death situation where the clock is reset, and the first contestant to achieve any score wins. Finally, if there is no score during this period, the winner is decided by Hantei (decision) of the referee and the two corner judges. According to Boguszewski,1 the Golden Score rule extends the combat time, and the longer the judo combat, the more aerobically dependent it becomes. Due to rules like the one just described and other factors, judo combat’s physiological demands are not easy to determine. The anthropometric variability among competitors is very high. The specific technical actions performed during contests can also be very diverse. The wide range of combats’ length (from seconds to minutes), as well as the existence of a series of effort cycles of rest and activity increases that variability. Therefore, it is difficult to quantify the effort displayed by an athlete during a contest.2

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Physiological response of high-level female judokas

physiological demands of a group of high-level female judokas through laboratory tests and field tests (tatami). Second, it aimed to prove the validity of the Santos test when applied to female judoists. Materials and methods Design overview In order to develop successfully our research project, we established a course of action that included two steps. First, we tried to find a group of female judoist that could fulfill the requirements of the study: 1) there had to be one athlete for each official (under 20) female weight category: -48 kg, -52 kg, -57 kg, -63 kg, -70 kg, and -78 kg (to avoid the influence of the subject’s weight on the results); 2) all subjects had to be, at least, black belt first dan (they could be considered expert judokas); 3) all of them had to be regional champions, and medallists at national championships or tournaments. This type of athletes practice 6 days a week all year round. Therefore, research conducted on them could be used to gather more information on the metabolic demands of judo combat in women. Moreover, this knowledge could be very helpful for coaches to establish training programs for competitive female judoists. Second, we designed an assessment protocol that included two parts: 1) laboratory testing: subjects were asked to run on a treadmill until exhaustion; 2) field testing: the Santos test was selected because previous research has shown that it complies with the principles of validity, specificity, individuality and reproducibility.11, 12 Moreover, the field test was also designed to match the laboratory test’s main features. The goal was to be able to compare the results of both assessment tools. The working hypothesis of this research project was that if the results obtained through the field test (Santos test) and the laboratory tests agree, the former could be considered a useful tool to design and assess training protocols for female high-level judokas.


Verkhoshansky 3 believes that judo demands explosive efforts, as well as the competence to confront exhaustion without reducing effectiveness. Furthermore, Pulkkinnen 4 considers that the anaerobic energy production system is the primary source of energy in judo combat. The high levels of lactate found in judokas uphold this view.5 However, Thomas et al.6 believe that they also need an adequate aerobic system to keep their performance at a high level throughout a combat. Moreover, Laskowski et al.7 confirmed that judo training improves both aerobic and anaerobic performance. Therefore, anaerobic metabolism appears to be important at the beginning of the combat, while aerobic metabolism seems to be significant towards the end.8, 9 Thus, resistance training has great relevance in judo. The main benefit of an aerobic capacity workout is the improvement of the anaerobic threshold. Wasserman and Mcllroy 10 introduced the idea of a threshold of the anaerobic metabolism: a gradual shift from an oxidative metabolism to a physiological state with slight presence of oxygen (anaerobic metabolism). The aerobic-anaerobic transition zone is the most important element to enhance the aerobic capacity and the aerobic power of athletes, and judo combat demands high levels of both energy systems. Previous research has proven the Santos test as a simple, specific, valid, reproducible, and reliable tool for determining the aerobic-anaerobic transition zone in competitive judokas.11, 12 To our knowledge, research conducted on female judoists is scarce. Leyk et al.13 studied maximal isometric hand-grip force, while Whyte et al.14 measured cardiac hypertrophy. Ebine et al.,15 Little 16 and Sbriccoli et al.17 determined maximal oxygen consumption. Ebine et al.15 also measured maximum heart rate. Finally, Baudry and Roux 18 evaluated maximal oxygen consumption, maximal heart rate and peak blood lactate, but the number of women that participated in the study was minimal (N.=2). Based on the aforementioned, the existing knowledge regarding the physiological characteristics of female judoists can be considered limited. Sex differences have been found in the nature of the physiological response to exercise.19 Therefore, there is a need to assess women judokas’ physiology through the Santos test. Based on the aforementioned, the present study had two primary aims. First, it sought to measure the

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Participants Eight high-level female judoist (under 20) volunteered to participate in the project. They had to fulfil


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Procedures

All subjects were required to stay away from exercise 24 hours before each testing session. They were also asked to avoid any food ingestion 3 hours prior to each trial. The time lapse between field and laboratory tests was always less than 7 days. Tests were conducted at the same time of the day. Before each one, all subjects performed the same standard warm up. Research shows that strenuous engagement in aerobic endurance sports may cause menstrual problems.20 Therefore, we scheduled all tests considering the menstrual cycle phases of the subjects. Both tests (laboratory and field) followed a stages progressive interval maximal protocol. The laboratory one used standard technology, it was done under standard conditions, and it followed internationally accepted scientific protocols to serve as a reference to determine if the information gathered from the field test was valid. Laboratory test. Stages progressive interval and maximal test (SPIM)

A treadmill (Laufergotest LEB, Germany) was used to carry out the test. Special environmental measures were implemented to ensure perfect ventilation. Meteorological conditions were kept constant throughout the whole trial (17-20 °C, 730-740 mmHg). A standard protocol was followed: 5 km.h-1 initial velocity, 2 km.h-1 velocity increments, 3-minutes effort stages, 5% treadmill inclination (constant), and

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Table I.—Anthropometric characteristics of the subjects. Age (year) Mass (kg) Height (cm) Body fat (%)

17.2±2.0 62.1±9.4 164.2±8.2 12.4±2.5

Values are mean ± SD.

30-second pause between effort stages. This protocol reflects the generally accepted recommendations for evaluating VO2 and/or HR in 3-minutes work steps.21 This type of SPIM test is widely used in sport research.22 Stegman et al.23 and Stegman and Kindermann 24 recommend a running protocol of 3 minutes per step with an intensity increment of 2 km.h-1 until exhaustion, as the best approach to determine the individual anaerobic threshold (IAT) (known also as lactate threshold according to Faude et al.25) Furthermore, the heart rate and the maximum oxygen uptake stabilize within this 3-minute time frame.26 Respiratory data was recorded using a CardioO2 & CPX/D gas analyser (Medgraphics, USA). The oxygen analyser was zirconium, while the carbon dioxide analyser was infrared. The ventilation was measured with a Hans-Rudolph mask fitted with a Pittot pneumotachograph calibrated before and after each test. Continuous electrocardiogram analyses were carried out to measure the subjects’ heart rate. Blood pressure was also measured with a precision mercury sphygmomanometer. Blood lactate was analyzed using an Accusport (Boehringer, Germany) machine.27 Gullstrand et al.22 have shown that no step on this type of test yields statistically significant differences between the lactate values in capillary blood or in heart rate. In addition, Beneke et al.28 found that such interruptions of the workload lead to a decrease in the lactate value only after a 30-minute work period (our laboratory tests lasted less than 30 minutes). The following parameters were evaluated: maximum heart rate (HRmax), heart rate at the anaerobic threshold (HR threshold), percentage of threshold heart rate with respect to the maximum (HR threshold %), maximum oxygen uptake (VO2max), blood lactate at the end of each effort stage and 3 minutes after the conclusion of the test (mmol.L-1), and lactate maximum (mmol.L-1). The criteria employed to determine the realization of the maximum effort was: respiratory quotient (RQ) ≥1, and HR ≥85% of the theoretical value. Franklin, Whaley and Howley 29 criteria were applied to finish the test.


these requirements: black belt first dan (expert judokas), regional champions, medallists at national championships, active competitors in official national tournaments, and a judo experience of more than 10 years. Prior to the beginning of the investigation, all procedures and a written consent according to the declaration of Helsinki were approved by the institutional research ethics committee. Subjects were informed of the experimental risks. Those who were over 18 years of age signed the written consent, and for those who were under 18, their parents had to sign the document. All subjects trained for 11 months completing the same working protocol, and their weekly training programme was identical too. Table I presents the main characteristics of the judokas who took part in the study.

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Field test. Santos test

plete the correct number of repetitions in 40 seconds. Most studies refer to judo combat as several intervals of activity and pause with a regular character.6, 4, 17, 30, 31 That is the reason why we divided the field test in two phases (activity and pause) that take place at a regular pace. Favre-Juvin et al.30 reported activity periods of 20 to 40 seconds with interruptions from 10 to 20 seconds. Therefore, we estimated that the best rate activity-pause was 40-15 seconds, respectively. Our goal was to match, as closely as possible, the real effort displayed by judokas in competition. During the field test, the judokas wore a VO2 2000 portable gas analyser (Med Graphics, USA). The dimensions of this system were: 11 cm length, 14 cm width, 6.5 cm thickness, and 1200 grams weight. It was calibrated before and after each test with Aerograph software (Windows 95 and 98 compatible). The ergospirometric parameters studied were oxygen uptake, carbon dioxide production, ventilation and respiratory coefficient. The heart rate was continuously recorded by means of a heart rhythm monitor (Polar S810, OY Finland), and it was digitalized using a Digital Wireless Industrial Transceiver (model Wit 2410 E, 2.4 GHz). Throughout the test, micro samples of arterialised blood were obtained to determine blood concentration of lactate. The samples were taken before the test, when the ventilation threshold was being reached (as determined from the data obtained in real time from the portable gas analyser), and 5 minutes after the end of the test. The test was considered finished when the athletes could no longer meet the quality requirements. The blood lactate was analyzed with the same equipment and procedure used in the laboratory test. In order to verify the validity of our proposal, the same parameters were studied in the field and laboratory tests. Each subjects’ IAT was measured using Keul’s procedures.32 This author considers that the workload, the VO2 or the treadmill velocity corresponding to the point cut by a tangent on the lactate curve with an angle of 51º represents the IAT of the subject.


It was designed to create an assessment tool that could mimic real competition conditions. Thus, it was implemented on a tatami (competition judo floor). Two judokas carried out the test: the subject and a supporting partner. Both of them belonged to the same weight category, and they were dressed in judo suits (judogi). During the test, each subject had to perform several sequences of three specific technical skills; the ones that she performs better and uses during competition (tokui-waza or special technique). Each sequence had two parts: 1) active phase: the judoka had to perform the specific technical skills without bringing the opponent to the floor. It lasted 40 seconds. The dependent variable was the number of repetitions carried out by the subject, which produced a progressive increase in the intensity of the trial. Three different technical skills were performed in successive sequences. In the first one, the subject raised her partner from the floor. In the second one, she unbalanced completely her opponent. In the third one, the subject chose to lift the opponent or unbalance her completely. Thus, the same sequence was repeated throughout the whole test: technique one performed in the first 40-second phase, technique two in the second 40-second phase and technique three in the third 40-seconds phase. The next cycle started again with the first technique, and continued with the same sequence until exhaustion; 2) passive phase: the judoka and her partner, grabbing each other with their hands (judo hold, kumikata), had to move from one side to the other of the tatami depicting a square on it: first, towards the left of the supporting partner; second, backwards; third, towards the right of the supporting partner, and fourth, forward to the starting point. This phase tried to match the displacements that take place in real combats. It lasted 15 seconds, and it was performed right after every active phase. It gave the test its intermittent character, a key element in judo training and combat. The progressiveness of the test was based on the increase of one repetition on each new 40-second series. The first active phase started with 7 repetitions, the 2nd had 8, the 3rd had 9, and so on, until exhaustion prevented the judoka from executing the specific technical skill with the required quality, which followed these rules: 1) the judoka was not able to raise her partner from the floor; 2) she could not throw her partner off balance, and/or 3) she could not com-

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Rating of perceived exertion (RPE) Morgan and Borg 33 observed that the rate of change in the RPE during prolonged work can be used as a sensitive predictor of the point of self-imposed exhaustion. The commonly employed Borg


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were: HRmax: 199.0 (5.0) beats.min-1, HR at the anaerobic threshold: 170.5 (3.2) beats.min-1, percentage of maximum heart rate at which the anaerobic threshold appears: 86.3 (2.2)%, lactate max: 11.8 (1.5) mmol.L-1, lactate threshold: 3.8 (0.1) mmol.L-1, VO2 max: 44.8 (7.3) mL.kg-1.min-1 and RPE: 18 (1.4) (Table II). Table II also shows the application of the statistical t-test to the means of the values obtained in the two tests. Thus, we were able to observe how the differences between the main data of both tests were not statistically patent in most of the parameters studied. The two exceptions were the maximum oxygen uptake and the maximum concentration of lactate. The mean data corresponding to the aerobicanaerobic transition zone of the subjects obtained through the laboratory tests were: HR: 171.5 (4.8) beats.min-1 and lactate: 3.8 (0.4) mmol.L-1. Similarly, the data obtained through the field (Santos) test were: HR: 170.5 (3.2) beats.min-1 and lactate: 3.8 (0.1) mmol.L-1. The differences between the data of both tests are not statistically different. To illustrate the field (Santos) test, Figure 1 shows the results of subject number 6 while performing it. The graphic line represents the relationship between the heart rate and the number of repetitions of the specific technical skill performed by the judoka.


6-20 Scale assumes a linear function between perceptual and physiological (VO2, HR) or physical (work rate) parameters.34 Recently, the use of RPE has been applied to resistance training in an effort to create a valid non-invasive way to monitor training intensity.35 However, there is no literature on RPE used in judo female athletes. The scale was explained before each trial. It remained in full view of the judokas for the duration of the tests, and they were asked to rate their perceived exertion at the end of each one. Statistical analyses

All statistical analyses were carried out using the SPSS 12.0 programme for Windows, applying the Student’s t-test, and considering the minimum level of significance as P