Fig. 1. Schematic illustrations of experimental setup. (A) An experimental bath containing a muscle preparation. DS, stimulator for direct stimulation; FT, force transducer; LS, He-Ne laser for monitoring sarcomere length; M, whole muscle preparation; NS, stimulator for nerve (indirect) stimulation; SC, screen for monitoring laser diffraction pattern; SM, servo-motor. The circulation of physiological saline is shown by thick arrows. The path of the laser light is shown by thin arrows. (B) Diagram of the electronic circuit used to drive a dual-mode servomotor (SM) for controlling muscle length and load and for recording muscle force. Force change was also measured by a force transducer (FT).