The Influence of Tension upon the Electrical Responses of Muscle to Repetitive Stimuli

Recent investigations by A. V. Hill (1), Meyerhof (2), Doi (3), and others have made it evident that the heat liberated and tension developed by skeletal muscle during contraction varies for single maximal stimuli as well as for short tetani with the initial passive tension of the muscle, increasing to a point as the initial tension is raised, and then decreasing as the initial tension is raised still further. The mechanism by which this adaptation to differing mechanical conditions is brought about remains as yet obscure. As it seemed possible that a study of the electric responses of muscle subjected to differing mechanical conditions might throw some light upon the question, the following experiments were undertaken. A review of the previous investigations upon this subject has recently been given by Forbes, Ray and Hopkins (4, 1923) in their paper on the effect of tension on the action current of the twitch.