Papers by Keyword: Swimming

Abstract: The purpose of this study was to evaluate the effects of aqueous extract from Atractylodes macrocephala (AME) on the physical fatigue. A total of 48 mice were randomly divided into four groups of 12 mice each: control (C), low-dose AME-treated (LAT), middle-dose AME-treated (MAT) and high-dose AME-treated (HAT) groups. The mice in the treated groups received AME (50, 100 and 200 mg/kg, respectively) intragastrically (ig) and the mice in the control group received distilled water ig. After 30 days, a forced swimming test was performed and the biochemical parameters related to fatigue were examined. The results suggested that AME could extend the swimming time to exhaustion of the mice, as well as increase the liver and muscle glycogen contents, and decrease the blood lactate and blood urea nitrogen levels. These finding indicates that AME had anti-fatigue effects.

Abstract: To explore the relationship between basal metabolism of the nicotinamide and the athletic ability of the elite swimmers, Sixteen Chinese male athletes participated in the short distance swimming competitions in the 15^th Asian Games were recruited. Their morning urine samples were collected three times in a row, once a week in the month before the games, and the metabolite of nicotinamide, N-methylnicotinamide, was measured using nuclear magnetic resonance (NMR). Then the subjects were classified as finalists group and non-finalists group according to their performance in the games, and mean comparisons of the measured results was carried out between the groups with SPSS15.0. The relative concentrations of MNA in the urine from finalists group were significantly higher than from non-finalists group in every comparison (0.0000524 ± 0.0000281 VS. 0.0000195 ± 0.0000131, P<0.05; 0.0000221 ± 0.0000181 VS. 0.0000162 ± 0.0000151, P<0.05; 0.0003831 ± 0.0000373 VS. 0.0000636 ± 0.0000118, P<0.05). Higher level swimmers have relatively higher metabolic rates, which may help to form a more effective energy supplying mechanism and a higher tolerance to intense training and severe competitions.

Abstract: Myliobatidae is a family of large pelagic rays including cownose, eagle and manta rays. They are extremely efficient swimmers, can cruise at high speeds and can perform turn-on-a-dime maneuvering, making these fishes excellent inspiration for an autonomous underwater vehicle. Myliobatoids have been studied extensively from a biological perspective; however the fluid mechanisms that produce thrust for their large-amplitude oscillatory-style pectoral fin flapping are unknown. An experimental robotic flapping wing has been developed that closely matches the camber and planform shapes of myliobatoids. The wing can produce significant spanwise curvature, phase delays down the span, and oscillating frequencies of up to 1 Hz, capturing the dominant kinematic modes of flapping for myliobatoids. This paper uses dye flow visualization to qualitatively characterize the fluid mechanisms at work during steady-state oscillation. It is shown that oscillatory swimming uses fundamentally different fluid mechanisms than undulatory swimming by the generation of leading-edge vortices. Lessons are distilled from studying the fluid dynamics of myliobatoids that can be applied to the design of biomimetic underwater vehicles using morphing wing technology.

Abstract: Although it is well known that the modes of undulatory locomotion of fish swimming provide high speed and high drive efficiency, it is hard to understand the propulsion mechanism of fish directly from living things. In the present study, in order to investigate hydrodynamic characteristics of the swimming modes, numerical simulation of flows around a deforming body of a rainbow trout which belongs to the kind of fish of subcarangiform undulatory swimmers was performed by using a Lagrangian vortex method. In this simulation, the basic configuration of the fish body is modeled with use of a NACA type airfoil, and the mode of undulatory motion is numerically given by a function obtained from observation of actual fish swimming. As a result of the present study, the relation between characteristics of propulsion force acting on the fish body and formation of complex vortex structures are clarified.