Biomechanics and Medicine in Swimming XI

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esults Table 1 shows a comparison between swimming velocities and the times of each phase. The average 5 m RTT was 5.62±0.33s for the Open turn, and 5.55±0.27s for the Apnea turn. There was no significant difference between the two turns but the 5 m RTT for the Apnea was shorter than for the Open turn for six of the 10 subjects. The mean times of the turnin phase and turn-out for the Apnea turn was significantly shorter than the Open turn but the pivot phase for the Apnea turn was significantly longer than the Open turn (p
BiomechanicsandmedicineinswimmingXi Mechanical and Propulsive Efficiency of Swimmers in Different Zones of Energy Supply Kolmogorov, s.V. 1,2 , Vorontsov, A.r. 2 , rumyantseva, o.A. 1 , Kochergin, A.B. 2 1 Pomor State University, Arkhangelsk, Russia 2 All-Russian Swimming Federation, Moscow, Russia Dimensionless coefficients for mechanical and propulsive efficiency (e g , e p ) have been studied using physiological and biomechanical methods in swimming various strokes. The research has been conducted in the three zones of energy supply: below the threshold of anaerobic metabolism (AT), above the zone of maximal oxygen consumption (VO 2 max ) and in the zone between AT and VO 2 max . The highest values of e g and e p for male and female swimmers have been revealed in the zone between AT and VO 2 max . In all the three zones of energy supply the values of e g are higher for male swimmers. At the same time the values of e p are equal for male and female swimmers. Key words: Metabolic and mechanical power, efficiency, velocity IntroductIon Development of efficient technologies to train swimmers assumes solving of an important theoretical and practical problem of interdependence between energy supply, on the one hand, and swimming biomechanics, on the other one. In case of biological objects’ steady non-stationary motion in water, at the first stage metabolic energy is transformed with losses into mechanical one, which at the second stage is transformed with additional losses into useful activity result, i.e. into swimming velocity. To describe precisely basic mechanisms of the phenomenon under study, this process of human swimming was formalised in form of mathematic model (Kolmogorov, 1997): v 0 =P ai × e g × e p /Fr � 110 f .d .� , (1) in which v 0 is mean swimming velocity at the competition or training distance (m·s -1 ); P ai is power of active energetic metabolism (W); e g is dimensionless coefficient of mechanical efficiency, i.e. ratio of total external mechanical power (P to ) to P ai ; e p is dimensionless coefficient of propulsive efficiency, i.e. ratio of useful external mechanical power (P uo ) to P to ; F r(f.d.) is frontal component of active drag force (N). Hence, the goal of this research has been to investigate experimentally regularities of metabolic energy transformation into swimming velocity at different zones of energy supply on the basis of equation 1. Methods The research was conducted at the period of spring training mesocycle lasting from January to April. Twenty-nine university swimmers (15 female subjects aged from 17 to 22 and 14 male subjects aged from 18 to 23) took part in the research. Correct studying of regularities of metabolic energy transformation into useful activity result is possible only in conditions when character and direction of training load carried out by the subjects during the training mesocycle, are taken into consideration. Therefore, the time of experimental investigation of this process in the three different zones of energy supply was coordinated with certain periods of purposeful technical and functional training. It is this circumstance that explains the order of tests. In February the first test was conducted in the zone of energy supply below the threshold of anaerobic metabolism (AT). Test 1 was carried out in a swimming pool on the basis of training series of 8×200 m by the basic stroke with 45 s breaks. In March the second test was conducted in the zone of energy supply above the maximal oxygen consumption (VO 2 max ). Test 2 was carried out in the flume, with peri-limiting metabolic power being applied in swimming by the basic stroke. The work lasted one minute for sprinters and two minutes for medium distance swimmers. In April the third test was conducted in the zone of energy supply between AT and VO2 max . Test 3 was carried out in the flume in the course of training series of 3×1 minutes (for sprinters) and 3×2 minutes (for medium distance swimmers) by basic stroke, intervals of work and rest being altered as 1:1. Preliminary, individual swimming velocities in all the three zones of energy supply were calculated for each subject on the basis of special tests in the swimming pool. To define experimentally variables in equation 1, a complex of physiological and biomechanical research methods was applied. The power of active energetic metabolism (Pai , W) in all the three tests was calculated as a ratio of energetic expenditures at the test distance (E, J) to work time at this distance (t, s). Energetic expenditures were defined experimentally by the method of indirect calorimetry. For this purpose, all necessary gaseous parameters of the ventilation air were measured with the help of the mobile system “MetaMax” and lactate concentration was determined in capillary blood before and after the test. When the research was conducted in the swimming pool (test № 1), gas analytical measurements were taken during rest breaks between training distances. When the research was conducted in the flume (tests № 2 and № 3), gas analytical measurements were taken before, during and after the test. All experimental results were reduced to conditions of STPD. Quantitative values of E were calculated on the basis of special equations (Capelli et al., 1998; Zamparo et al., 1999), which correspond entirely to the three studied zones of energetic supply and are described in detail in the specified papers. Total external mechanical power (Pto ), frontal component of active drag force (Fr(f.d.) ) and useful external mechanical power (Puo ) were defined using a biohydrodynamic method (Kolmogorov, 2008), which consists of a complex of independent biomechanical and hydrodynamic methods to measure necessary physical values. At first, total external mechanical power (Pto max ) was defined by the method of small perturbations at the maximal swimming velocity (v0 max ) (Kolmogorov et. al., 1997). Afterwards, the corresponding value of Pto exp was calculated for every experimental swimming velocity in the studied zones of energetic metabolism (v0 exp ) on the basis of the well-known (Touissant and Truijens, 2005) and verified experimentally dependence between these parameters (Kolmogorov and Koukovyakin, 2001): 3 3 Pto exp =Pto max /v0max× v0exp . (2) The frontal component of active drag force under conditions of swimmer’s steady non-stationary forward motion (Fr(f.d.) ) was defined experimentally for every experimental swimming velocity (v0 exp ) using the corresponding hydrodynamic method (oriented specially to measure this physical value) (Kolmogorov, 2008). This paper describes in detail the theory, necessary mathematic models and practical technology to define Fr(f.d.) within the whole range of v0 exp relevant for the research. Useful external mechanical power (Puo ) was defined from the following equation: P uo = Fr (f.d.) × v0exp. (3) When the parameters, indicated above, were defined for every experimental swimming velocity in the studied zones of energetic metabolism (v 0 exp ), dimensionless coefficients of mechanical (e g =P to exp /P ai ) and propulsive (e p = P uo / P to exp ) efficiency were calculated. results Tables 1 and 2 represent experimental results of the studied process in dolphin swimming by a female subject and in brass by a male subject, correspondingly. These tables give only key parameters of P ai , e g , e p , F r(f.d.) and v 0 exp which are necessary to solve quantitatively equation (1) and
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average VO2 measured during resting
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Pahlen Norge AS Pahlen Norge AS Cha
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