Intermittent Muscular Work

Abstract

The physiological effect of rest pauses on a non‐steady state work (2,160 kpm/min) was studied. A physically well trained subject performed in one hour a total amount of 64,800 kpm on a bicycle ergometer by intermittent work with 0.5, 1, 2 or 3 min periods of work and rest. Total O 2 intake, total pulmonary ventilation, total number of heart beats and blood lactic acid concentration during the work hour and during recovery were determined. It was found that the heavy work when split into short periods of work and rest (of 0.5 or 1 min duration) was transformed to a submaximal load on circulation and respiration and was well tolerated during one hour. With longer periods (of 2 or 3 min duration) the work output got close to the upper limit of performance and could be fulfilled only with the utmost strain. These findings are discussed from a physiological and practical point of view. In order to explain the low lactic acid values during the short periods of work and rest it was proposed that the myohemoglobin has an important function as an oxygen store during short spells of heavy muscular work.