Browsing by Author "Bell, George Hamilton"

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    The effects of two breathing patterns on selected physiological parameters during a simulated 200 yard freestyle in male swimmers
    Bell, George Hamilton (Virginia Polytechnic Institute and State University, 1978)
    Ten male adolescent and young adult swimmers were examined to determine the effects of two breathing patterns on selected physiological parameters during a simulated 200-yard freestyle swim. Specifically, a comparison of oxygen uptake, blood lactic acid, ventilation and the respiratory exchange ratio responses to a timed swim were made under two experimental breathing conditions. The intensity of the experimental trials was maintained at approximately 95% of the subjects' maximal workload to induce maximal effort. The validity of capillary blood samples for the use of micro-determination of blood lactic acid was established prior to the preliminary and experimental trials. Maximal physiological parameters for each subject were then obtained during the Preliminary Test using a maximal intermittent tethered swimming test. The experimental phase of the study consisted of four 110 sec swims designed to simulate competitive 200-yard freestyle swimming. Two swims were conducted under Condition 1, wherein the subject swam breathing once every arm cycle. The remaining two swims were under Condition 2, wherein the subject swam breathing every alternate arm cycle. Using Pearson product-moment correlation to determine within condition reliability for each dependent variable, it was found that oxygen uptake, blood lactic acid and ventilation were reliable. Under Condition 1, the respiratory exchange ratio was also found to be reliable, however, under Condition 2, the reliability coefficient was considered unacceptable. Therefore, the respiratory exchange ratio was excluded from further analyses. Hotelling's T² was employed on the linear combination of oxygen uptake, ventilation, and blood lactic acid between conditions. This analysis indicated a significant difference (p<.05) between conditions. Simultaneous confidence intervals indicated that oxygen uptake, blood lactic acid, and ventilation were the variables causing the difference. Simple linear and stepwise regression were employed to determine the extent to which the dependent variables contributed to the V̇O₂ (ml/kg·min⁻¹) in each experimental condition. Under Condition 1, the respiratory exchange ratio was found to be closely associated with the V̇O₂ in that condition. Under Condition 2, ventilation was found to be most closely associated with the lower V̇O₂ observed in this condition. It was deemed important to determine the extent to which changes between conditions in the dependent variables contributed to changes in the V̇O₂ (ml/kg·min⁻¹) between conditions. It was found that the changes in ventilation contributed only a small portion to the changes in V̇O₂ between conditions, which indicated that something other than the dependent variables was associated with the changes in V̇O₂ between conditions. During training and performance, the evidence suggests that under a given workload, greater metabolic capacity was required when breathing every stroke. In addition, higher intensities of work could be tolerated when breathing was done only during alternate strokes.