Biomechanics and Medicine in Swimming XI

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average age of 27.1 ± 5.9 years. When selecting subjects, the prerequisite was to have at least one year of training and competitive experience in triathlon, as well as being of satisfactory health. Table 1: Descriptive parameters AS±SD (min-max) AGE (yrs) 27.1 ± 5.9 (18-39) body height (cm) 174.85 ± 7.28 (165.0-187.0) body mass (kg) 72.65 ± 11.18 (58.7-92.7) %BF (%) 13.4 ± 7.72 (4.0-26.2) AGE – years, body height (cm) , body mass (kg), %BF - Subcutaneous Body Fat Sample of Variables a) A set of variables for evaluating anthropometric characteristics Measurement of examinees’ morphological characteristics was carried out in accordance with the guidelines of the International Biological Program (IBP, Mišigoj-Duraković 2008). Basic morphological variables were measured in order to determine the examinees’ morphological status. With the help of anthropometric instruments and a medical scale, the variables of body mass and body height were measured, while the subcutaneous body fat was established based on the method of biological impedance, using the Tanita BC-418 (TANITA, USA) scale. Eight electrodes (4 for the arms, 4 for the feet) are used to send a weak electric signal through the entire body. In those locations where the resistance, i.e. impedance is higher, the signal needs more time to travel, indicating a higher content of subcutaneous body fat. b) Set of variables for evaluating functional abilities 1)FS max (BPM ) - Maximum Heart Frequency, 2) V max (m/s) Maximum Speed, 3) LAC max (mmol/l) - Maximum Lactates, 4) FS anp-1 (BPM) - Anaerobic Threshold Heart Frequency („intersection method“), 5) FS anp-2 (BPM) - Anaerobic Threshold Heart Frequency („4 mmol/l“), 6) FS anp-3 (BPM) - Anaerobic Threshold Heart Frequency („D-max method“), 7) LAC anp-1 (mmol/l) - Anaerobic Threshold Lactates („intersection method“), 8) LAC anp-2 (mmol/l) - Anaerobic Threshold Lactates („4 mmol/l“), 9) LAC anp-3 ( mmol/l) - Anaerobic Threshold Lactates („D-max method“). Specified parameters were measured during one test protocol, while the variables were determined based on three various methods. Prior to testing, the examinees were acquainted with the testing protocol which, with regard to the swimming test, consists of seven (7) 200 meter sections with a 5 minute active rest regime in a small swimming pool. Each section is covered by applying a faster swimming pace, up to the maximum and at an even pace. How fast each examinee swam through a certain section was determined based on the best 200 meter result, the same being tested a few days prior to the swimming test. The obtained result was increased by 5 seconds in order to get the fastest seventh section. Every previous section is also increased by 5 seconds in order to get the swimming pace for each set section which the swimmer must comply with. An example of calculating swimming speed for each of the set sections is shown in Table 6. Specified swimming pace was dictated by an assistant by the pool, using a whistle every 12.5 m, and if the examinee was swimming at a set pace, then the assistant would whistle every 25 or 50 m. During testing, the examinees wore a pulse meter (Polar RS 400, Finland) the whole time, and at each section’s end, the concentration of lactates in the blood was measured with a Lactate Scout device (SensLab, Germany). Immediately prior to starting a new section (about 15-30 seconds prior), the examinee would enter the pool and prepare for start. In order for the transmitter of the pulse meter to chaPter3.PhysioLogyandBioenergetics be attached to the examinees’ chests, all the examinees wore swimsuits. Results obtained by measurement procedures were processed by a data analysis software system Statistic version 8.0. In order to determine statistically significant differences between various methods used to establish the anaerobic threshold of the subjects, the t-test was used for dependent samples. results Assessed means, standard deviation, minimal and maximal results, skewness and kurtosis for certain variables is presented in Table 2. Ttest for dependant variables showed that there is no statistical significant difference between FS anp-1 and FS anp-3 (Table 3). Table 2: Descriptive Values of Certain Variables Valid N Mean Minimum Maximum Std.Dev. Skewness Kurtosis FSmax 13 180.15 170 192 7.50 0.065 -1.342 LACmax 13 11.31 6.6 19.2 2.99 1.236 4.098 Vmax 13 1.13 0.96 1.36 0.11 0.415 0.139 LACanp-1 13 4.63 3.3 6 0.80 0.015 -0.705 LACanp-2 13 4.00 4 4 0.00 -- -- LACanp-3 13 4.98 3.3 7.3 1.15 0.521 0.006 Table 3: T-test and Correlation Results FSanp-1 FSanp-2 FSanp-3 P < .05000 FSanp-1 FSanp-2 FSanp-3 R 1 0.88 0.91 t (p) 3.87 (0.0022) -1.95 (0.07) R 0.88 1 0.74 t (p) 3.87 (0.0022) -3.92 (0.0020) R 0.91 0.74 1 t (p) -1.95 (0.07) -3.92 (0.0020) High correlation values (Table 3) are indicative of a link between FS anp-1 and FS anp-2 which shows that the purpose of measurement is the same and that predicting results by using the D-max method based on the „intersection” method is 82% successful, while predicting results through the D-max method based on the 4 mmol/l method is much less successful, i.e. 54%. dIscussIon Large differences between maximum values of lactate in the blood suggest various degrees in which the body is able to react to acidosis. Naturally, those values are conditioned by training as well, and if looking at each examinee separately, it is noticeable that examinees that are more trained are able to increase speed one section after another, regardless of the rise of blood lactate and the decrease of pH value. Said values of maximum blood lactateise a generally accepted aerobic capacity parameter and the buffering ability of the muscles. Values of the maximum heart frequency in this test are the highest value achieved in a test, but the maximum. In order to achieve maximum heart frequency values, the test must be shorter, without intervals and more intense. It would be logical that there are no statistically significant differences between all these measures because the object measured is the same. Table 3 shows a high correlation (r=0.91) between FSanp-1 („intersection“ method) and FSanp-3 (D-max method), while the t-test for dependant samples showed (Table 3) that no statistically significant differences exist, the same demonstrating that those two different measures for determining the anaerobic threshold are reliable in evaluating the anaerobic threshold in swimmers. 239
BiomechanicsandmedicineinswimmingXi Furthermore, Table 3 shows that a statistically significant difference exists between FSanp-2 (4 mmol/l method) with FSanp-1 and FSanp-3, thereby proving it to be a deviating measure, meaning that it does not target the same qualities. According to Stegmann and associates, 1981, it is impossible to fix the threshold at 4mmol/l for everyone (FSanp-2), so therefore it is necessary to determine the so called IAT – individual anaerobic threshold (FSanp-1). In their research, Stegman and Kindermann have shown that the individual anaerobic threshold is different in relation to the threshold obtained by a fixed concentration of lactates at 4mmol/l. The „Intersection” method, i.e. the individual anaerobic threshold represents a reliable way of evaluating the lactate anaerobic threshold (Urhausen, 1993), and if carried out carefully it provides overall consistent results with athletes or within the clinical population (Svedahl and MacIntosh, 2003). Establishing the anaerobic threshold at 4mmol/l has its advantages, considering the objectivity of determination, but also a great disadvantage due to ignoring individual differences and individual lactate kinetics. That is, not all examinees show a significant increase of lactate at 4 mmol/l, but this range is much wider, spanning from 3-6 mmol/l, up to as much as 9 mmol/l (MacIntosh and Assoc., 2002.; Billat and Assoc.2003). Figure 1: Comparison of FSanp Percentage Values from FSmax Obtained by Three Different Methods Figure 1: Comparison of FSanp Percentage Values from FSmax Ob- It tained is important by Three to Different know that, Methods on average, untrained persons will exceed the threshold at only 50-60% of maximum load, while top athletes in aerobic sports do the same at 85- 95% It is important of maximum to load know (Janssen, that, on 2001). average, The untrained percentage persons values will of exceed FSanp incidence are very the threshold high and at should only 50-60% not be taken of maximum literally, load, since while unfortunately top athletes maximum in values of heart aerobic frequency sports do have the same not been at 85-95% obtained. of According maximum load to Maglischo, ( Janssen, 2003, 2001). the maximum heart frequency value for swimmers must be tested in the water, while an additional The percentage values of FSanp incidence are very high and should not prerequisite of obtaining maximum heart frequency values is reading the values during or be immediately taken literally, after since maximum unfortunately performance maximum lasting values between of heart one and frequen- two minutes. cy have not been obtained. According to Maglischo, 2003, the maximum CONCLUSION heart frequency value for swimmers must be tested in the water, while an Today, additional there prerequisite are several of definitions obtaining maximum of the term heart anaerobic frequency threshold. values is The anaerobic threshold is considered to be the intensity at which the oxygen supply system activates reading the values during or immediately after maximum performance the mechanism of anaerobic glycolysis in a more significant way, and at which the accumulation lasting between of one lactic and acid two is minutes. equal to its breakdown. The method most often used in practice is the ventilation method, but its application in water is almost impossible, whereas conclusIon the second mostly used method is the heart frequency deflection point that can be Today, determined there are on several a heart definitions frequency of curve the term obtained anaerobic from threshold. a continuous The test. For that reason, anaerobic testing threshold in the is water considered is significantly to be the more intensity difficult, at which thereby the making oxygen the anaerobic threshold determination more difficult as well. In the course of this research, three methods supply system were used activates to determine the mechanism the anaerobic of anaerobic threshold: glycolysis 1) the in „intersection” a more method (IAT), significant 2) the way, 4mmol/l and at which method, the and accumulation the 3) D-max of lactic method. acid is Both equal the to „Intersection” method its breakdown. and the The D-max method method most have often been used shown in practice to be a is reliable the ventilation manner of evaluating the method, anaerobic but its threshold, application and in if water applied is almost carefully impossible, they provide whereas generally the consistent results second in mostly swimmers. used method is the heart frequency deflection point that can be determined on a heart frequency curve obtained from a continuous test. For that reason, testing in the water is significantly more difficult, thereby making the anaerobic threshold determination more dif- 240 85,00 80,00 75,00 %FSanp‐1 %FSanp‐2 %FSanp‐3 ficult as well. In the course of this research, three methods were used to determine the anaerobic threshold: 1) the „intersection” method (IAT), 2) the 4mmol/l method, and the 3) D-max method. Both the „Intersection” method and the D-max method have been shown to be a reliable manner of evaluating the anaerobic threshold, and if applied carefully they provide generally consistent results in swimmers. reFerences Billat, L.V., Sirvent, P., Py, G., Koralsztein J., Mercier, J. (2003). The Concept of Maximal Lactate Steady State. Sports Med 33(6), 407- 426. Janssen, P. (2001). Lactate Threshold Training. Human Kinetics. USA. Kindermann, W., Simon, G., and Keul, J. (1979). The significance of the aerobic-anaerobic transition for the determination of work load intensities during endurance training. Eur. J. Appl. Physiol. 42, 25-34. MacIntosh, B.R., Esau, S., Svedahl, K. (2002). The lactate minimum test for cycling: Estimation of the maximal lactate steady state. Can. J. Appl. Physiol, 27, 232-249. Maglischo, 127 E. (2003). Swimming Fastest. Human Kinetics, UK. Mišigoj-Duraković M. Kinantropologija. Biološki aspekti tjelesnog vježbanja (Kinanthropology. Biological Aspects of Physical Exer- range is much wider, spanning from 3-6 mmol/l, up to as much as 9 mmol/l (MacIntosh cise). Faculty of Kinesiology, University of Zagreb, 2008; 130-150 and A graphical Assoc., 2002.; overview Billat of and FSAssoc.2003). anp values shows that the lowest values of Sjodin, B., Jacobs, I., and Karlsson, J. (1981). Onset of blood lactate ac- FSanp-2 , i.e. heart frequency were determined by the 4 mmol/l method. cumulation and marathon running performance. Int. J. Sports Med. 2, A graphical overview of FSanp values shows that the lowest values of FSanp-2, i.e. heart frequency A higher similarity were determined of incidence by the and 4 mmol/l higher values method. between A higher FSsimilarity anp-1 and of incidence 23-26. and FSanp-3 higher are values also clearly between visible. FSanp-1 and FSanp-3 are also clearly visible. Stegmann H, Kinderman W, Schnabel A. (1981). Lactate kinetics and the individual anaerobic threshold. International Journal of Sports Medi- 100,00 cine. 2, 160-165. Swedahl K., MacIntosh B.R. (2003). Anaerobic threshold: The concept and 95,00 methods of measurement. Can. J. Appl. Physiol. 28 (2), 229-323. Urhausen, A., Coen, B., Weiler, B., and Kindermann, W. (1993). In- 90,00 dividual anaerobic threshold and maximum lactate steady state. Int. J. Sports Med, 14, 134-139.
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Pahlen Norge AS Pahlen Norge AS Cha
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