Bundles of muscle fibres were isolated from the diaphragm of mouse, rat and rabbit. Mean oscillatory power output was determined during phasic stimulation and imposed sinusoidal length changes. Maximum power output was measured over a range of cycle frequencies. The cycle frequency for maximum power output (fopt) decreased with increasing body mass and was described by the equation, fopt=4.42M−016, where M is body mass. A very similar relationship has been reported between body mass and the frequency of the trot-gallop transition in terrestrial, quadrupedal mammals [Heglund et al. (1974), Science186, 1112-1113), and the significance of this similarity is discussed.

Keywords:
diaphragm, locomotion, mechanics, muscle, oscillatory work, power output, scaling effects
© 1991 by Company of Biologists
1991
You do not currently have access to this content.