THE KINETICS OF OXYGEN SUPPLY IN ULTRA-SHORT RUNNING ON A TREADMILL
Christensen, E. H., Hedman, R., & Saltin, B. (1960). Intermittent and continuous running. (A further contribution to the physiology of intermittent work.) Acta Physiologica Scandinavica, 50, 269-286.
Intermittent running on a treadmill at a speed of 20 km/h (12.4 miles/hour) was analyzed and a comparison between this work and continuous running at the same speed was performed. The results were in agreement with the assumption that stored oxygen plays an important role in the oxygen supply during short spells of heavy work. When running intermittent 6.67 km in 30 minutes (effective work 20 minutes and rest 10 minutes), a trained S attained a total 02 uptake of 150 liters. With an 02 uptake of 0.4 liters/minute at rest standing at the treadmill, or 4 liters per 10 minutes of rest, 146 liters of 02 were due to the 20 minutes of work. The actual uptake at work was only 101 liters and if normal values are assumed during rest pauses, a deficit in oxygen transport of 45 liters arose during the 20 minutes of actual work. This quantity was taken up during the 120 rest pauses of five seconds each. Two thirds of the oxygen demand during the 120 work periods of 10 seconds each was accordingly supplied by oxygen transported with the blood during work, and one third was covered by a reduction in the available oxygen stores in the muscles, which in turn were reloaded during the subsequent five-second rest periods.
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