Biomechanics and Medicine in Swimming XI

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Tethered Force Production in Standard and Contrastandard Sculling in Synchronized Swimming diogo, V. 1 , soares, s. 1 , tourino, c. 2 , Abraldes, J.A. 3 , Ferragut, c. 4 , Morouço, P. 5 , Figueiredo, P. 1 , Vilas-Boas, J.P. 1 , Fernandes, r.J. 1 1 University of Porto, Faculty of Sport, Cifi2d, Porto, Portugal 2 University of Vigo, Faculty of Education and Sport Sciences, Spain 3 University of Murcia, Faculty of Sports Sciences, Murcia, Spain 4 Catholic University of Murcia, Faculty of Sports Sciences, Murcia, Spain 5 Polytechnic Institute of Leiria, CIMH, Portugal Studies carried out in synchronized swimming are scarce, inclusively with respect to the biomechanical analysis of sculling. The purpose of this study was to measure the force produced in standard and contrastandard sculling, using a 30 s maximal tethered synchronized swimming test. 13 synchronized swimmers performed a 2x30 s maximum intensity tethered synchronized swimming test, in standard and contrastandard sculling conditions, respectively. The variables were: absolute and relative maximal force, the time when maximal force occurred, the mean force, the mean values of maximal and minimal force, and the fatigue index. Results showed that higher values of maximal force were found in the standard sculling. The Fatigue Index evidenced that the maximal force declined with time in all participants and in both sculling conditions. Key words: biomechanics, sculling, synchronized swimming, tethered swimming IntroductIon Synchronized swimming is a technical and physically demanding sport, in which the strength and the velocity of movements are combined with high flexibility requirements (Chu, 1999). In this sport, sculling is an often-used technique, consisting in underwater arm stroke patterns whose purpose is the production of hydrodynamic force. This force will allow support, balance and propulsion of the swimmer’s body (Chu, 1999). Although the importance of sculling in synchronized swimming is undeniable, very few studies were conducted, and none seem to have quantified the force produced by the swimmer. The appearance of fatigue during sculling was also not yet studied. Knowing that there is a high relationship between strength and performance in swimming (Risch and Castro, 2007), and that strength training (with emphasis on neural adaptations) explains, in part, the specific positive changes in velocity and aerobic performance due to a better economy of movement (Hoff et al., 2002), the purpose of this study was to measure the force and the fatigue produced in standard and contra-standard sculling in synchronized swimming, using a 30s maximal tethered test. Methods Thirteen synchronized swimmers with the same performance level v vvolunteered to participate in this study. Mean (± SD) physical characteristics of the sample were: age 15.8 (2.1) years; body weight 50.5 (8.2) Kg; height 160.9 (7.4) cm; arm span 161.2 (9.7) cm. A 30 s tethered swimming protocol was used in order to determine individual force to time - F (t) - curves in two conditions: (i) standard sculling (movement towards the head, with the body placed in supine position, the arms in the lateral of the trunk, the wrist in dorsal flexion and the hand palm oriented toward the feet) and (ii) contra-standard sculling (movement towards the feet with the body in supine position, the arms in the lateral of the trunk, the wrist in palmar flexion and the hand palm oriented towards the head). After familiarization with the equipment and a standardized warm-up, each subject performed a 30 s maximum intensity tethered synchronized swimming test. Individual chaPter2.Biomechanics F (t) curves were obtained with the subjects attached by a non-elastic cable to a strain-gauge system (Globus, Italy). The beginning and the end of the test were established through an acoustical signal produced by a researcher. Tests were conducted in an indoor, heated (27.5ºC), and 2 m deep swimming-pool. The absolute and relative maximal forces (Fmax and RFmax, being RFmax = Force.body weight -1 ), the time at which Fmax occurred (FmaxTime), the mean force (Fmean), the average of Fmax (FmaxAvg = average of all force values in the first 5 s of the test), the average of minimal force (FminAvg = average of all force values in the last 5 s of the test) and the fatigue index (FI (%) = ([FmaxAvg-FminAvg)/Fmax- Avg]x100) were computed. The force values of the first 2 s test were eliminated in order to remove the high inertial values associated with the first pull (Fig. 1). After the normality of the distributions was confirmed (Kolmogorov-Smirnov test), T- Test for repeated measures was used to compare mean values of each variable obtained for standard and contra standard sculling techniques. Pearson product-moment correlation coefficient was also computed for the study of relevant association of variables. Significance level was established at 95% (p
BiomechanicsandmedicineinswimmingXi (r=-0.58) and Fmean (r=-0.81) for standard action, and with FminAvg (r=-0.91 and r=-0.54) for both sculling variants. Table 2. Individual and Mean ± SD values of absolute maximal (Fmax) and relative (relative Fmax) force, the time when the Fmax occurred (Fmax Time), mean force (Fmean), the average of maximal and minimum forces (FmaxAvg and FminAvg, respectively) and the fatigue index (FI) in contra-standard sculling (n=13). Swimmer Fmax (N) 68 Relative Fmax (N/Kg) FmaxTime (s) Fmean (N) FminAvg (N) FmaxAvg (N) FI (%) #1 32.2 0.63 2.3 15.5 8.3 24.4 66.2 #2 37.2 0.71 4.1 21.4 17.0 25.9 34.3 #3 30.4 0.53 4.8 15.5 11.3 19.5 41.9 #4 31.1 0.70 9.6 16.6 12.2 20.6 40.6 #5 32.9 0.73 4.9 13.5 11.5 18.5 37.7 #6 35.4 0.80 3.4 16.2 13.9 20.0 30.4 #7 41.9 0.67 3.1 15.8 11.9 20.8 42.8 #8 24.0 0.72 2.9 12.5 10.5 14.7 29.0 #9 30.0 0.67 6.9 16.3 14.7 19.3 23.7 #10 34.0 0.64 6.2 18.9 13.7 25.4 47.2 #11 43.6 0.69 2.5 24.3 18.6 32.7 43.2 #12 35.8 0.66 8.1 19.1 16.8 23.8 29.2 #13 40.8 0.82 3.9 23.4 19.6 26.5 26.2 X ± SD 34.6±5.4* 0.69±0.07* 4.8±2.3 17.6±3.6 13.8±3.4 22.5±4.6 37.9±11.3 *Different (p
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average VO2 measured during resting
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Figure 2. Repeatability of the LTin
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• Without restriction; • Blinde
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etween experimental groups and cont
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Pahlen Norge AS Pahlen Norge AS Cha
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