Biomechanics and Medicine in Swimming XI

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Capacity level (in %) 75 70 65 60 55 50 45 40 35 30 25 20 15 y = 91.9195x -0.1846 R 2 = 0.9986 0 250 500 750 1000 1250 1500 1750 2000 Time (s) Wat Females Figure 3. Following model of Capacity Vertical Swim Abilities Model (CAP vswim ). dIscussIon The female WP players showed the following VSA: they could sustain the vertical position in water at all the energetic intervals with the average load of 22.32, 18.98, 17.30, 14.82, 13.57, 11.03, 9.17, 8.02 and 6.55 kg, respectively. The values obtained were at the levels of 34.81, 29.53, 26.88, 22.96, 20.99, 16.99, 14.07, 12.27 and 9.98 % of BM, respectively. With respect to the capacity model, the players showed VSA at the following capacity levels: 69.69, 60.42, 55.69, 48.58, 44.94, 37.42, 31.77, 28.20 and 23.54 % of the hypothetical maximum, respectively. Previous research has established that female water polo players have great anaerobic capacity and muscular strength of the upper body (peak power - 8.05±0.8 W·kg -1 , mean power - 6.5±0.4 W·kg -1 ), a very high level of aerobic endurance (VO 2 peak - 46.52±7.0 mL∙kg −1 ∙min −1 ) on the arm ergometer tests, (VO 2 peak - 61.8±11.9 mL∙kg −1 ∙min −1 ) on the leg ergometer tests, and high values of lung function parameters. The great strength of the upper body and pronounced aerobic endurance of the whole organism are dominant characteristics of elite female water polo players. Along with a relatively pronounced body height and a low percentage of fat tissue, these female athletes are very well predisposed for adaptation to great physical demands over the whole match (Radovanovic et al., 2007). With regard to Time-Motion analysis of international women’s water polo match play, it was established that the average exercise bout duration was 7.4 ± 2.5 s and exercise to rest ratio within play was 1:1.6 ± 0.6. The average pattern of exercise was represented by 64.0 ± 15.3% swimming, 13.1 ± 9.2% contested swimming, 14.0 ± 11.6% wrestling, and 8.9 ± 7.1% holding position. Significant differences existed between the outside and the center players for percentage time swimming (67.5 ± 14.0% vs 60.2 ± 13.3%, P = 0.002) and wrestling (9.9 ± 9.3% vs 18.4 ± 11.1%, P = 0.000). Also, a significant difference was found in the number (P = 0.017) and duration (P = 0.010) of high-intensity activity (HIA) bouts performed in each quarter for the outside (1.8 ± 2.2 bouts, 7.0 ± 3.4 s) and the center players (1.2 ± 1.5 bouts, 5.2 ± 3.4 s). The authors concluded that international women’s water polo match play was characterized by a highly intermittent activity. Swimming, particularly that of high intensity, had greater significance for the outside players whereas wrestling had greater significance for the center players (D’Auria & Gabbett, 2008). Regarding the data presented by D’Auria and Gabbett (2008), approximately 40% of the intensive duel play, i.e., wrestling, lasts between 2 and 5 s, c. 19% lasts 5 – 10 s, while c. 8% lasts 10 – 15 s. In other words, about 67% (2/3) of a given situation is realized with sub-maximal and maximal intensity within 2 to 15 s, i.e., in anaerobic-alactic energetic system of swim effort. Our study established that the players tested in the above-mentioned time intervals of 5, 10 and 15 s could sustain the vertical position with the respective additional loads of 34.81, 29.53 and 26.88 % of their body mass (Table 1). Such data can indicate the requirement for particular considerations in developing maximal and chaPter3.PhysioLogyandBioenergetics repetitive strength or power in an anaerobic working regimen both in basic water training and additional land training of female water polo players so as to improve specific anaerobic endurance of the lower limbs (Bampouras & Marrin, 2009). When the results of this study on ABS vswim, REL vswim and CAP vswim values were used to calculate the Fatigue index (which is expressed as the extra weight load decline – that is, observed vertical swimming value results reached in 5 s as the peak power abilities minus observed vertical swimming value results reached in 30 s as the minimum power abilities – divided by the time interval in seconds between the peak and the minimum of the observed vertical swimming values, i.e. divided by 25), the following was obtained: Fi aps = 0.30 kg -s , Fi rel = 0.47 %BM -s , and Fi cap = 0.84 %b -s . The comparison of results in vertical swimming abilities between the present and the previous study (Dopsaj & Thanopoulos, 2006), which nevertheless tested male elite water polo players using the same methodology, the following gender differences can be inferred: a) With regard to absolute test results, the women players were able to sustain the vertical swimming position for the same time intervals (5, 10, 15, 30, 45, 120, 300, 600 and 1800 s) with less additional load of 14.11, 11.89, 10.78, 9.13, 6.95, 6.61, 5.36, 4.57 and 3.56 kg, respectively. b) With regard to absolute test results, the women players were able to sustain the vertical swimming position for the same time intervals (5, 10, 15, 30, 45, 120, 300, 600 and 1800 s) with a lower percentage of additional load of 38.73, 38.51, 38.38, 38.11, 33.88, 37.48, 36.91, 36.32 and 35.22 %, respectively. Generally speaking, with regard to absolute additional load values the female players‘ abilities were lower (37.06 %) than the male players, i.e. their average abilities comprised 62.94 % of the comparative men‘s abilities. conclusIon For the water polo training plan, consideration needs to be taken of the primary informative sources, i.e. the physiological demands of the game based on the game duration and the different technical and tactical demands during the game according to player position. The resulting models should be used to control the fitness levels, as well as to assist the development of training technology with WP female players. reFerences Bampouras, T. M. & Marrin, K. (2009). Comparison of two anaerobic water polo specific tests with the Wingate test. Journal of Strength and Conditioning Research, 23(1), 336-340. D’Auria, S. & Gabbett, T. (2008). A Time-Motion analysis of international women’s water polo match play. International Journal of Sports Physiology and Performance, 3, 305-319. Dopsaj, M. & Thanopoulos, V. (2006). The structure of evaluation indicators of vertical swimming work ability of top water polo players. Revista Portuguesa de Ciencias do Desporto (Portugese Journal of Sport Sciences), 6(2),124-126. Gastin, P. B. (2001). Energy system interaction and relative contribution during maximal exercise. Sports Medicine, 31(10), 725-741. Marrin, K. & Bampouras, T. M. (2008). Anthropometric and physiological changes in elite female water polo players during a training year. Serbian Journal of Sports Sciences, 2(3), 75-83. Platanou, T. (2009). Cardiovascular and metabolic requirements of water polo. Serbian Journal of Sports Sciences, 3(3), 85-97. Radovanovic, D., Okicic, T. & Ignjatovic, A. (2007). Physiological profile of elite women water polo players. Acta Medica Medianae, 46(4), 48-51. Tan, F., Polglaze, T. & Dawson, B. (2009). Comparison of progressive maximal swimming tests in elite female water polo players. International Journal of Sports Physiology and Performance, 4, 206-217. 193
BiomechanicsandmedicineinswimmingXi Critical Velocity and the Velocity at Maximal Lactate Steady State in Swimming espada, M.A., Alves, F.B. Faculty of Human Kinetics - Technical University of Lisbon, Portugal The purpose of this study was to compare critical velocity (CV) to the velocity at maximal lactate steady state (MLSSv) in swimming. Eighteen well-trained male swimmers performed a maximal 400 m front crawl to estimate maximal aerobic velocity (V400) and two to three 30min constant velocity swims in order to directly determine MLSSv. CV, estimated from 200 m and 400 m maximal swims, was highly correlated to MLSSv (r = 0.94 and p < 0.01) and V400 (r = 0.95 and p < 0.01). However, CV was significantly faster than MLSSv, confirming that this parameter does not represent a steady metabolic rate in long distance swimming. Nevertheless, CV still seems to be a useful tool for aerobic conditioning evaluation, due to the simplicity of its determination. Keywords: exercise; swimming; Maximal lactate steady state; critical Velocity IntroductIon The maximal tolerated duration of a constant-load high-intensity swimming bout has been shown to be a hyperbolic function of the power (or velocity) of the exercise (Wakayoshi et al., 1992), similarly to other forms of human locomotion (for a review, see Morton, 2006). According to this model, the velocity-duration relationship has an asymptote on the velocity axis, termed the critical velocity (CV) that has been considered as a valid fatigue threshold and a marker of the transition between the heavy and the severe intensity domains (Poole et al., 1988), since it has also been shown to be a close correlate of the highest metabolic rate associated with pulmonary oxygen uptake (VO2), acid-base status and blood lactate concentration that can be sustained for a certain time at a constant level. The power output or the velocity corresponding to the CV has also been considered as expressing the maximal lactate steady state (MLSS) (discussed in Pringle and Jones, 2002), although this equivalence has not been confirmed in many experimental studies, especially in swimming (Dekerle et al., 2005b). The MLSS corresponds to the highest workload or velocity that can be maintained over time without a continuous blood lactate accumulation (Billat et al., 2003) and its measurement demands several subsequent constant load tests that have to be performed with different workloads on different days, until it is possible the determine an individual workload intensity above which the rate of lactate production exceeds lactate clearance. However, the number of studies directly assessing this parameter is surprising limited in swimming, due surely to the time-consuming and cumbersome procedures required, when compared to the performance of an incremental graded test for lactate threshold determination. The purpose of this study was to compare critical velocity (CV), estimated by a two-component model, using 200 m and 400 m maximal swims, to the velocity at maximal lactate steady state (MLSSv) in welltrained swimmers. Methods Eighteen male national and international level competitive swimmers volunteered for this study. They were aged 17.1 ± 2.8 years, with a height of 177.6 ± 5.7 cm, a body mass of 65.8 ± 9.1 kg and a% body fat of 10.1 ± 2.4%. Subjects have trained regularly for at least 6 years and took no drugs or medicaments during the study. Most of the swimmers were familiar with swimming pool exercise testing procedures. They were informed of the nature of the experiments and gave written consent to participate in this study. 194 Athletes were instructed to avoid exhausting exercise the day before the tests and to retain their normal nutritional habits. A standardize warm-up of 600 m was completed in every testing session. A maximal 400 m front crawl was performed in order to use the average velocity between 50 m and the 350 m (V400) as an estimate of the maximal aerobic velocity (Lavoie and Leone, 1988). CV was calculated from the slope of the regression analysis between the averaged velocity of the 400 m trial previously referred to and a 200 m front crawl maximal trial performed for this purpose. In a first round of testing, six subjects performed 30-min constant velocity swims at 75 and 80% of V400. The physiological impact of these bouts was clearly low so it was decided to continue the study using higher intensities. All eighteen subjects performed, then, in random order, 30-min at constant velocity at 85, 90 and 95% of V400. Split times for each 50 m were determined and used by two investigators positioned at 7.5 m and 17.5 m of the pool to control the athletes swimming pace. The swimmer was asked to maintain the pre-established swim pace as long as possible. The test was interrupted when the swimmer could no longer match the required swimming velocity. Each subject was stopped every 400 m (30 to 45 seconds) for blood sample collection and record of the rate of perceived exertion (MLSSrpe) (6-20 scale). Maximal lactate steady state blood lactate concentration (MLSSc) was defined as the highest blood lactate concentration that increased by no more than 1 mmol.L-1 during the final 20-min of a 30-min constant workload (Beneke, 2003; Baron et al., 2005). When this criterion was not accomplished, the test was stopped. MLSSv was the intensity associated with MLSS. Tests were conducted at similar times on separate days (1 day of total rest between tests) at a 25 m pool with the water temperature at 28.2º C. No polyurethane suits were used. Stroke rate (SR) was measured from three stroke cycles taken in the middle of the pool for every 50 m and stroke length (SL) calculated. Blood lactate concentrations were analyzed using a Lactate Pro LT device (Arkray, Kyoto, Japan). A Polar Sport Tester (S410) recorded the heart rate frequency every 5 seconds during all tests. Paired-samples t-test was used to compare CV and MLSSv. Pearson’s linear coefficient was used to test correlations. Statistical significance was accepted at p < 0.05. results Mean and standard deviation of V400, MLSSv, CV and MLSSc are shown in Table 1. MLSSv corresponded to 89.7 ± 1.2% and CV to 94.0 ± 1.5% of V400. Only one swimmer achieved MLSS at 85% of V400. At 95% of V400 no one achieved stabilization in blood lactate concentration, confirming that work bouts at this intensity were performed above MLSS. Extreme values of 2.6 and 7.8 mmol.L -1 were found associated to MLSSv. Mean SR at MLSSv was 32.9 ± 4.3 (cycles.min -1 ) and mean SL was 2.49 ± 0.34 (m.cycle -1 ). Mean heart rate frequency at MLSSv (MLSS HR ) was 177.0 ± 6.9 beats.min -1 and the mean MLSSrpe expressed by the swimmers was 13.39 ± 1.33. Table 1. Mean and standard deviation of V400, MLSSv, CV and MLSSc. N=18 V400 (m·s-1) MLSSv (m·s-1) CV (m·s-1) MLSSc (mmol·L-1) 1.49 ± 0.07 1.34 ± 0.06 1.40 ± 0.08 5.3 ± 1.6 CV was significantly faster than MLSSv (p < 0.01) and both expressed velocities significantly different from V400 (p < 0.01).
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Pahlen Norge AS Pahlen Norge AS Cha
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