title: Dependence of the heat production of active muscle on the length of muscle.
abstract: The dependence of the heat production of muscle on length was examined in isometric (with stretch) and isotonic (free of stretch) tetanuses of 2 s. The isometric heat production was significantly greater than the isotonic one at any length of muscle. The isometric heat coefficient (Flo/Q, where F is the active tension development of muscle measured in ponds, lo is the resting length measured in cm, Q is the heat production during the contraction at a given length measured in mcal) was not constant but dependent on the length of muscle, and had an extreme value near the resting length (lo). A close positive correlation was found between the active tension development and the heat production of the muscle.
mesh_terms: D000818:Animals; D001001:Anura; D006358:Hot Temperature; D009119:Muscle Contraction; D009132:Muscles / Q000502:physiology* / Q000648:ultrastructure; D009929:Organ Size; D011893:Rana esculenta; D013816:Thermodynamics