Studies on the Physiological Load of Cycling

Abstract

To estimate the value of physiological load of cycling with special reference to cardiorespiratory responses, oxygen intake, pulmonary ventilation and heart rate was measured directly during seven kinds of bicycle ergometer work in the laboratory, and heart rate during outdoor cycling were also obtained by the telemetry method for seven healthy young males of ages from 19 to 21 years.physiological load was expressed by % of maximal oxygen intake (% of Vo2 max.). Maximal oxygen intake was directly measured by the Daglas Bag method, and oxygen intake levels were estimated indirectly from heart rate levels during cycling using the regression equations determined for each individual between directly measured oxygen intake and heart rate. Outdoor cycling was made under the following conditions: (a) Twenty-one kinds of conditions which consisted of 5, 10, 15, 20, 25, 30 and 35 km per hour of cycling speed and 1, 67 (40×24), 2.35 (40×17), 3.13 (50×16) gear ratios of pedaling. (b) Long distance cycling tour of about 120 km as a prolonged exercise.Results obtained were as follows: (1) High significant correlation was obtained between oxygen intake and heart rate for each subject. (2) When cycling speed was increased to 15 km per hour on level ground, physiological load gradually reached the level of 30%Vo2 max. However, when increased to 30 or 35 km, it was indicated abrupt increase at 80 or 900 level, (3) There was significant different of physiological load among gear ratio of pedaling, (4) In the case of long distance cycling tour, heart rate was changed from 94 to 164 beats per minutes, so that predicted levels of physiological load was between 45 to 75% of Vo2 max.