Biomechanics and Medicine in Swimming XI

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Both Resistance Factor (Rf ) and Gliding Coefficient (Gc) measure loss of speed, but they present their own advantages. Klauck’s gliding test methodology has the advantage of not having a cable attached to the swimmer’s hip and the possibility to compare with trials preceded of a turn. The proposed methodology uses of a velocity meter and offers the possibility to calculate parameters like maximum speed, glided distance, instantaneous velocity and gliding coefficient Gc within any chosen period of gliding time. This peculiarity has been of great help to determine the precise instant to quit gliding and to start underwater kicking on starts and turns. conclusIon Starts and turns can be cut-off and analysed by parts. As a result, experts are able to better define lacks on technique and establish priorities in training sessions to reach the best performance. A well-balanced solution between accuracy, validity and applicability for the evaluation of underwater glide has been found. Coaches have designed and included specific exercises for the training of the glide, starts and turns in everyday practice and sport science have increased their presence in the everyday work of swimmers. When applied on young swimmers, the gliding test seems to be of great use for talent detection. reFerences Chow J.W., Hay J.G., Wilson B.D. and Imel C. (1984). Turning technique of elite swimmers. Journal of Sports Sciences, 2. pp 241-255. Clarys J.P. (1979). Human morphology and hydrodynamics. International Series on Sport Science Vol 8: pp 3–41, University Park Press, Baltimore. Klauck J. and Daniel K. (1976). Determination of man’s drag coefficients and effective propelling forces in swimming by means of chronocyclography. In: P V Komi (ed.) Biomechanics V B. Human Kinetics Pubishers. pp 250-257. Lyttle A.D., Blanksby B.A.B., Elliott B.C. and Lloyd D.G. (1998). The effect of depth and velocity on drag during the streamlined glide. Journal of Swimming Research. 13: pp15- 22. Maiello D., Sabatini A., Demarie S., Sardella F. and Dal Monte A. (1998). Passive drag on and under the water surface. Journal of Sports Sciences, 16(5), pp 420-421. AcKnoWledGeMents I would like to thank coaches from Spanish and Catalan Swimming Federation and Paralympic Committee, as well as my sport’s sciences colleagues from GIRSANE (Research Group from Olympic Training Centre in Barcelona, Spain). chaPter2.Biomechanics Effects of a Blueseventy TM Bodysuit on Spatialtemporal and Coordinative Parameters During an All-out 50-m Front Crawl silveira, r.P., Kanefuku, J.Y., Moré, F.c., castro, F.A.s. Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil The aim of this study was to establish the effects of using a shoulder to ankle bodysuit (Blueseventy TM ) on spatial-temporal and coordinative parameters during an all-out 50m front crawl swim. Six subjects (16.6 ± 2.0 yrs) performed two all-out 50m trials (with and without bodysuit). The arm stroke parameters and index of coordination were determined by videography. A repeated measures ANOVA was performed, with main effects verified using LSD post-hoc for an α < 5 %. Using the bodysuit, swimming speed and stroke length were higher. The duration of the entry and catch phase and non-propulsive phase were shorter in the second 25 m split. No statistical differences in index of coordination were found. Wearing the bodysuit significantly improves the swimming performance, mostly on the second half of the test. Key words: high-tech bodysuits, swimsuits, coordination, front crawl IntroductIon The implementation of new technology in order to enhance sports performance has resulted in a range of new equipment that can be used during training and competition. Most prominent among these advances has been the development of highly technical bodysuits purported to improve swimming performance. The original purpose of these swimsuits was to decrease drag by mimicking sharkskin. The latest bodysuits, however, also appear to improve buoyancy and compress body parts (Benjanuvatra et al., 2009). The body suits have been further developed through the use of particular fabric and by the manner in which the suits are sewn. Indeed, the most advanced bodysuits have no sewed parts at all. The evolution of high technology bodysuits is almost certainly a major factor in the recent spate of new world records in swimming events. As a result, questions have been raised concerning the fabric composition and availability as well as ethical and legal issues linked to wearing these suits in competitions. FINA subsequently banned the bodysuits in indoor competitions from January 2010. But the suits are free to be utilized in open water and triathlon events. Furthermore, there does not exist enough research on the effects of using bodysuits on swimming performance. Spatial-temporal parameters, as well as the index of coordination proposed by Chollet et al. (2000), appear to be dependent on restrictions of the organism, the environment and the task (Seifert et al., 2007). Thus, the purpose of this study was to establish the effects of using a bodysuit (Blueseventy TM ) on spatial-temporal and coordinative parameters during an all-out 50m front crawl performance. Considering the improvement in performance (Benjanuvatra et al., 2009), increased stroke length and swimming velocity and a greater continuity in propulsion actions (index of coordination near zero) were expected wearing the bodysuit. Methods Subjects: Six subjects, each competitive at Brazilian age group national level, took part in this investigation (age: 16.6 ± 2.0 yrs; body mass: 67.8 ± 5.9 kg). All participants signed a consent form prior to which the aims, risks and procedures associated with this trial had been fully explained. The sample size was limited by the Blueseventy TM bodysuits availability. Trials: The subjects performed two all-out 50m trials in a 25 indoor pool, starting in the pool. One trial was performed with an ordinary 165
BiomechanicsandmedicineinswimmingXi suit (short made by Lycra) and one using a BlueseventyTM bodysuit that covered from the shoulders to the ankles. The order of the trials was randomized and the subjects rested for 20 min between the trials. The subjects used their own bodysuits during the trials. Video sampling and analysis: Two synchronized sub-aquatic video cameras (SANYO VPC-WH1), operating at 30 Hz, were used to acquire images in the sagittal plane of the swimmers. The cameras were positioned on the lateral sides of the pool and were carried manually using chariots on rails. To determine the stroke phases, two experienced researchers made a frame-by-frame analysis as reported before by Chollet et al. (2000) using the software VirtualDub v1.8.7. A third independent video camera operating at 25 Hz ( JVC, GR- DVL9800) was positioned 4 m above the water surface in the middle of the pool deck to measure race parameters. This camera allowed us to quantify swimming speed and stroke rate, from which stroke length was calculated. The analysis of the images was performed with the software Dgeme v.1.0. Index of coordination and arm stroke phases: Index of coordination (IdC) was taken to represent arm coordination, as proposed by Chollet et al. (2000). The index of coordination was expressed as a percentage of the duration of one arm stroke and represents the time between the end of propulsive action of one arm and the beginning of propulsion with the other arm, considering the mean of both the right and left arms. Therefore it is possible to quantify a catch-up (IdC < 0%), an opposition (IdC = 0%) or a superposition coordination mode (IdC > 0%). The duration of the stroke phases were expressed in absolute values (s), divided into four phases: (1) entry and catch: from the entry of the hand into the water to the moment prior to the beginning of its backwards movement relative to the body, (2) the pull: from the beginning of hand’s backwards movement until the moment where the hand is in a plane vertical to the shoulder, (3) the push: from the point where the hand is below the shoulder until its release from the water and (4) the recovery: from the point of water release to the hand re-entry into the water. The pull and push phases were considered the propulsive ones and the entry and catch and the recovery were considered the nonpropulsive phases of the stroke. Mean, standard error and deviation, normality and sphericity were calculated and verified for all the analyzed variables. To verify the effects of the bodysuit and the split of the trial (first or second 25 m split) on selected variables, a repeated measures ANOVA was performed (mixed model 2 x 2 – two suits and two 25 m splits), with main effects verified using LSD post-hoc. For the stroke phases where there was an interaction between the split and suit condition, the Student-t test for paired samples was used. The level of significance was set at 95% (p
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Figure 1. General biomechanical par
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average VO2 measured during resting
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Figure 2. Repeatability of the LTin
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etween experimental groups and cont
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Pahlen Norge AS Pahlen Norge AS Cha
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