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Author Perret, Claudio ♦ Spengler, Christina M. ♦ Egger, Ginette ♦ Boutellier, Urs
Source CiteSeerX
Content type Text
File Format PDF
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Endurance Exercise ♦ Med Sci Sport Exerc ♦ Respiratory Muscle Performance ♦ Healthy Subject ♦ Resistive Breathing ♦ Exhaustive Cycling ♦ Constant Resistance ♦ Trans-diaphragmatic Pressure ♦ Breathing Endurance ♦ Objective Measure ♦ Male Subject ♦ Min T0 V ♦ Cycling Exercise ♦ Transdia-phragmatic Twitch Pressure ♦ Peak Oxygen Consumption ♦ Previous Finding ♦ Constant-load Cycling Exercise ♦ Extra-diaphragmatic Muscle ♦ Constant-load Run-ning ♦ Mag-netic Stimulation ♦ Possible Extra-diaphragmatic Muscle Fatigue ♦ Maximal Oxygen Consumption ♦ Diaphragmatic Fatigue ♦ Global Respiratory Performance ♦ Phrenic Nerve ♦ Present Study ♦ Exhaustive Cycling Endurance Test ♦ Key Word ♦ Different Intensity ♦ Min T10 ♦ Respiratory Muscle Fatigue ♦ Respiratory Performance ♦ Exercise Intensity
Abstract exercise above 85 % of maximal oxygen consumption, the diaphragm of healthy subjects can fatigue. Although a decrease in trans-diaphragmatic pressure is the most objective measure of diaphragmatic fatigue, possible extra-diaphragmatic muscle fatigue would not be detected by this method. The aim of the present study was to investigate the impact of exhaustive, constant-load cycling exercise at different intensities on global respiratory performance determined by the time to exhaustion while breathing against a constant resistance. Methods: Ten healthy, male subjects performed an exhaustive cycling endurance test at 65, 75, 85, and 95 % of peak oxygen consumption (V ˙ O2peak). Before cycling (t0) as well as at 10 min (t10) and 45 min (t45) after cycling, respiratory performance was determined. Results: Breathing endurance was equivalently reduced after exhaustive cycling at either 65 % (8.4 6 4.1 min [t0] vs 3.9 6 2.8 min [t10]), 75 % (9.9 6 6.1 vs 4.4 6 2.8 min), 85 % (9.3 6 6.0 vs 3.8 6 2.9 min), or 95 % V ˙ O2peak (8.5 6 5.1 vs 4.0 6 2.5 min) and, therefore, was independent of exercise intensity. Conclusion: This result contradicts previous findings, possibly due to the fact that extra-diaphragmatic muscles are tested in addition to the diaphragm during resistive breathing. Key Words: RESISTIVE BREATHING, RESPIRATORY MUSCLE FATIGUE During high-intensity, exhaustive, constant-load run-ning or cycling exercise above 85 % V ˙ O2max (1-3,12) or 80 % Wmax (18), the diaphragm of healthy subjects can fatigue—as shown by a reduction of transdia-phragmatic twitch pressure (Pdi,tw) during electrical or mag-netic stimulation of the phrenic nerves. At intensities of
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Education Level UG and PG ♦ Career/Technical Study