Kabaddi is a traditional outdoor game played with minor variations in all regions of India and most parts of Asia. Kabaddi requires tremendous physical stamina, agility, individual proficiency, neuromuscular coordination, lung capacity, quick reflexes, intelligence and presence of mind on the part of both attackers and defenders. [1]

Kabaddi is an intermittent type of sport, it requires both aerobic, anaerobic endurance with a well-built physique. The energy demands of kabaddi involve all the three systems for production of energy. [1]

The high intensity bursts of kabaddi are fuelled by anaerobic glycolysis system. These activities require rapid energy transfer that exceeds that supplied by stored phosphagens (ATP- phosphocreatine).It is suggested that a high anaerobic power is a required characteristic of kabaddi players. [2] Blood lactate levels can be used to reflect the capacity of the anaerobic glycolysis system. Capacity to generate high lactate levels during exercise enhances maximal power output for short durations. [2]

There are three major systems available for the production of energy in the muscles: the Adenosine Triphosphate- phosphocreatine (ATP- PC) system for high-intensity short bursts; the anaerobic glycolysis system for intermediate bursts of relatively high intensity and finally, there is the aerobic system for long efforts of low to moderate intensity. [2] It is well documented that there is a significant relationship between aerobic capacity i.e. VO2max (V- Volume consumed, O2- Oxygen, max- maximum) and the total distance covered and frequency of sprints made in a match.[3]

Thus, the possession of desirable anthropometric and physiological characteristics will have a greater advantage in executing a better performance in competition. [4] The physiological demands of various sports disciplines have been extensively studied, however, studies on the physiological demands of Kabaddi are lacking. [5-9] A systematic evaluation of the physiological demands of Kabaddi have not yet been undertaken in an organized way.[1, 10, 11] Keeping this perspective in mind, this study was planned to evaluate and compare the aerobic capacity (VO2max) and the anaerobic capacity (blood lactate level) in Kabaddi players with that of controls.

Aim Of The Study

To study aerobic and anaerobic capacities in Kabaddi players and compare them with normal population.

Objectives 1. To determine VO2max values and plasma lactate in Kabaddi players and controls.

2. To compare VO2max values and plasma lactate of Kabaddi players with that of controls.

The approval of the Institutional Ethics Committee was obtained before commencement of study. Selection of the Subjects: Kabaddi players from local colleges in the age group of 18 to 24 years, who have been playing regularly for more than three years, and have played kabaddi tournaments at various levels were selected as subjects. Fifty players were recruited in this group. Inclusion Criteria: 1. Kabaddi players who were playing regularly and have participated in various levels of kabaddi tournaments for more than three years. 2. Age: All the players were in the age group 18 to 24 years. 3. Sex: All the players were males. 4. Apparently healthy – not having any chronic disease. 5. Subjects who gave their consent for the study. Exclusion criteria: 1. Subjects having symptoms of cardiopulmonary disease, or history of any chronic disease. 2. History of smoking. 3. History of trauma or injury 4. Subjects not ready to participate voluntarily in the study Selection of the Controls: Individuals in the age group of 18 to 24 years, who were having a normal active lifestyle with no involvement in any athletic activity were selected as controls. Fifty individuals were included in this group. Inclusion Criteria: 1. Individuals who were having an active lifestyle with no involvement in any athletic activity. 2. Age: Individuals were in the age group 18 to 24 years. 3. Sex: All the Individuals were males. 4. Apparently healthy – not having any chronic disease. 5. Individuals who gave their consent for the study. Exclusion Criteria: 1. Individuals having symptoms of cardiopulmonary disease, or history of any chronic disease. 2. History of smoking. 3. History of trauma or injury. 4. Individuals not ready to participate voluntarily in the study. In the present study, VO2max and plasma lactate values of kabaddi players and controls were estimated and compared. For each parameter, the mean value and standard deviation were calculated. ‘Unpaired t test’ was applied to test whether the differences in means were statistically significant. A ‘p’ value of less than 0.05(p < 0.05) was considered to be statistically significant. A ‘p’ value of less than 0.001(p < 0.001) was considered to be statistically highly significant.

Total 100 participants were included in the study group. Fifty of them were subjects who were kabaddi players and fifty were controls with normal lifestyle. All the 100 people from the study group were males in the age group of 18 to 24 years. The mean values for the age, body weight, height and body mass index in kabaddi players were 21.38 ±1.9 years, 60.4 ± 2.69 kg, 174.7±

2.72 cm and 19.79 ± 0.99 kg/ m2 respectively. The mean values for age, body weight, height and body mass index in controls were 21.28 ±1.78 years, 61.6 ± 3.46 kg, 173.88 ± 4.78 cm and 20.43

± 1.78 kg/m2 respectively. (Table 1) .

The mean value of VO2max was 59.08 ± 3.33 ml/kg/min in kabaddi players, and 42.92 ± 3.39 ml/kg/min in controls. (Table 2). When mean values of VO2max (ml/kg/min) were compared in kabaddi players and controls using ‘unpaired t test’, it showed statistically highly significant difference with ‘p’ value less than 0.001. (Table 2)

The mean plasma lactate values were 105.1 ± 9.53 mg/dl in kabaddi players and 66.84 ± 7.38 mg/dl in controls. When mean values of plasma lactate were compared in kabaddi players and controls using ‘unpaired t test’, it showed statistically highly significant difference with ‘p’ value less than 0.001. (Table 2)

Table 1. Comparison of the Baseline characteristics of the Study Groups.

SD: Standard Deviation

Table-2            Comparison of VO2 max and plasma lactate in the Study Groups.

** p < 0.001: statistically highly significant.

In the present study, VO2 max and plasma lactate values of fifty kabaddi players (subjects) and fifty controls were estimated and compared. In this study the kabaddi players had a high VO2 max (aerobic capacity), as compared to the controls, and the difference was statistically highly significant.

The mean VO2 max of kabaddi players has typically been reported to be in the region of 55 to 65 ml/kg/min. However, these values are relatively modest in comparison with elite endurance athletes in other sports such as rowing, cycling or running. To some extent, this may be explained by the high volume of matches completed over the competitive season that reduce the opportunities for aerobic fitness training. Several researchers have proposed that a VO2max of about 60 ml/kg/min is a minimal threshold for elite professional male athletes. Aerobic endurance training has the potential to optimize kabaddi performance by enhancing recovery from high intensity intermittent bouts during match play. Thus; it is of importance to monitor the aerobic endurance performance of athletes and kabaddi players. The increase in aerobic capacity can probably be explained by the various physiological mechanisms discussed below:

1. Two distinct fiber types have been identified in skeletal muscle: fast twitch and slow twitch. Slow twitch fibers also called as Type I fibers have a contraction speed about one half as fast as its fast twitch counterpart. Slow twitch fibers possess numerous mitochondria and high enzyme concentration to sustain aerobic metabolism. They demonstrate a much greater capacity to generate ATP aerobically than fast twitch fibers. As such, slow twitch muscle fiber activation predominates in endurance activities that depend almost exclusively on aerobic metabolism. Fast twitch fibers also called as Type

II fibers, have a rapid contraction speed and become activated in sprint activities that depend entirely on anaerobic metabolism for energy. Kabaddi requires a blend of both aerobic and anaerobic capacities. Both types of muscle fibers are activated in it. Specific exercise training improves the metabolic capacity of both the fiber types.[2]

2. Training significantly increases capillary density and mitochondria size and number. The concentrations of enzymes and transfer agents involved in aerobic metabolism also increase two to three fold, enhancing the capacity to generate ATP aerobically, particularly via fatty acid breakdown. [2]

3. Resting heart rate in untrained individuals averages about 70 beats per minute, resting cardiac output averages 5 litres per minute. Resting heart rate in trained athletes averages about 50 beats per minute, resting cardiac output is 5 litres per minute. Thus, blood circulates with a proportionately larger stroke volume of 100 millilitres per beat. The two factors probably interact as aerobic fitness improves:

• Increased vagal tone slows the heart, allowing more time for ventricular filling.

Enlarged ventricular volume and a more powerful myocardium eject a larger volume of blood with each systole.

4. The following equation shows an important relationship between maximum cardiac output, maximum a-vO2 difference (extraction of Oxygen), and VO2max:- VO2max = maximum cardiac output × maximum a-vO2 difference .

Two mechanisms for Oxygen supply can increase a person’s oxygen uptake capacity: Increased tissue blood flow • Use of relatively large quantity of oxygen that remains unused by tissues at rest (i.e. expand the a-v O2 difference). [2]

5. Training increases the pulmonary capacities of the players. Mehrotra P.K et al studied the pulmonary functions in Indian sportsmen playing different sports. They assessed the relation between the quality of exercise performed and the quantitative effect of these exercises on the lungs. Pulmonary function tests of sportsmen engaged in various sports were compared with each other and with that of the controls. Players playing football, hockey, volleyball, swimming and basketball were chosen for this study. Medical students were chosen as controls. The parameters taken into account in this study were forced vital capacity (FVC), forced expiratory volume (FEV), and peak expiratory flow rate (PEFR). The results indicate that all the sportspersons had higher values of lung functions compared to the controls. [12]

The plasma lactate were compared in kabaddi players and controls and found statistically highly significant .Thus, the lactate generating capacity of kabaddi players was more compared to the controls. The increased plasma lactate values in kabaddi players may be explained by the following physiological mechanisms:

1. Improvement in the metabolic capacity of Fast twitch fibers also called as Type II fibers, which have a rapid contraction speed and become activated in sprint activities that depend entirely on anaerobic metabolism for energy.

2. Increased intramuscular glycogen stores with training contribute a greater amount of energy via anaerobic glycolysis.

3. Increase in glycolytic enzyme activity, particularly phosphofructokinase.

4.  Differences in training level, capacity to buffer acid metabolites produced in heavy exercise, and motivation contribute to individual differences in capacity to generate short-term anaerobic energy. [2]

Effects of Training: Short-term supermaximal exercise on a bicycle ergometer, in trained subjects always produces higher levels of blood and muscle lactate and greater muscle glycogen depletion compared to untrained counterparts. Better performances usually associate with higher blood lactate levels; supporting the belief that training for brief, all-out exercise enhances the glycolytic system’s capacity to generate energy. In sprint and middle-distance activities, individual differences in anaerobic capacity account for much of the variation in exercise performance. [2]

Buffering of Acid metabolites:Lactate accumulates when anaerobic energy transfer predominates. This increases the muscle’s acidity, negatively affecting the intracellular environment; decreased pH adversely affects contractile capacity and the enzymes. This has caused speculation that anaerobic training might enhance short-term energy transfer by increasing the body’s buffering capacity (alkaline reserve) to enable greater lactate production.[3]

Motivation: Individuals with greater “pain tolerance,” “toughness” or ability to push beyond the discomforts of fatiguing exercise definitely accomplish more anaerobic work. These people usually generate greater levels of blood lactate and glycogen depletion. Motivation plays a key role in obtaining better performance at all levels of competition. [ 2]

The mean VO2 max was 59.08 ± 3.3 ml/kg/min in kabaddi players and 42.65 ± 3.20 ml/kg/min in controls. The difference was statistically highly significant (‘p’ value less than 0.001). The mean plasma lactate values was 105.1 ± 9.54 mg/dl in kabaddi players and 66.74 ± 7.18 mg/dl in controls. The difference was statistically highly significant (‘p’ value less than 0.001). Thus, the kabaddi players showed a superior aerobic capacity (VO2max) as well as anaerobic capacity (plasma lactate values). Although, all that is required in a competition to succeed and can not always be measured in a lab, more research in the area of sports is needed in India to study the physical and physiological characteristics of Indian kabaddi players and compare it with international standards.

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