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Term Papers on Swimmers
Swimmers Swimmers lack a fixed point in the water from which to push. In moving the body forward, the swimmer also moves water backwards. The water acquires a kinetic energy change. Thus, propulsion in swimming involves two forms of power output: 1) to move the body forward by overcoming drag, and 2) that imparted to the "compression" of the water that is moved backwards. If gravitational and hydrostatic forces are ignored (the velocities occurring in the vertical direction are rather small), two forces remain: the propulsive force acting on the hands and feet and the drag force acting on the body. This study used the MAD system developed in Holland to measure forces associated with horizontal movement. Special facial valves were developed to minimize increased drag so that gas analyses could be measured. The gross efficiencies ranged from 5.1% to 9.5%, measures that are slightly below those obtained for arm cranking and wheelchair riding. The reduction is probably due to the extra energy required to overcome the hydrostatic pressure on the thoracic cavity and to compensate for heat loss of the body to the water. The amount of power consumed to push the water ranged from 30-50%. Implication. Efficiency increases as the speed of swimming increases. Therefore, when considering efficiency it must be relevant to a particular speed. There is no difference between males and females in movement efficiency at the same speed of swimming. When looking at other studies concerning efficiency, it is necessary to determine if those studies have or have not accounted for the movement of water backward in their assessments. The relationships between swimmers' biomechanical arm pulling pattern and technical ability were assessed in four "skilled" and five "less-skilled" athletes (the grouping being determined by a statistical method using all measures). The freestyle stroke was divided into five phases: entry (plus flight), downsweep, insweep, outsweep, and upsweep (round-out). VO2max, height, arm span, hydrostatic lift (maximum weight to maintain a balanced position under water), speed on a standardized 400 yd swim, and competition 500 yd time were measured. VO2max explained 64% of a 400 yd swim performed at 94% of 500 yd pace. Hydrostatic lift was the next most important structural variable. There was no significant difference between the two performance groups on any anthropometric, performance, or physiological variable. Biomechanical variables did differentiate the groups although there was great variation between individuals (e.g., as much as four times for entry duration and more than twice the time taken on the other stroke sections): stroke rate was higher in the skilled group; stroke rate was negatively related to stroke length; stroke length was shorter in the skilled group; both entry and stroke pattern were related to hydrostatic lift; downsweep phase was inversely related to upsweep; and longer outsweep and superposition of arm actions favored better swimming efficiency. Swimming mechanics were the primary factors differentiating the two groups. Even though the size of the groups was small, these variables were strong enough to overcome that deficiency. Implications 1.Having a good aerobic capacity is the basic requirement for fast long-distance swimming performances. 2.The stroke pattern should emphasize the last part of the underwater stroke rather than the entry. 3.Gliding and excessive stretching under water after the entry should be minimized so that deceleration between individual arm cycles does not occur. 4.Swimming improvements are likely to be greater and more easily achieved through technique developments rather than through physiological and anthropometric factors. Frontal areas, cross-sectional areas, and lengths of body segments were measured on 12 members of the University of Iowa men's swimming team during the Big Ten Championships over two years. Data were gathered through photo... This is ONLY a preview of the article. If you would like to view the entire document, you must subscribe to Digital Term Papers. Please register below now! Digital Term Papers has over 63,000 essays, term papers, and book notes online. Many paper sites will charge you hundreds of dollars for a single paper. Digital Term Papers only charges $14.95 for a one month membership with instant account activation! Don't waste anymore time! Join NOW!!!
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