Frangioni J V, Kwan-Gett T S, Dobrunz L E, McMahon T A
Biophys J. 1987 May;51(5):775-83. doi: 10.1016/S0006-3495(87)83404-5.
Frog gastrocnemius muscles stimulated isometrically in a saline bath at 20 degrees C were found to produce a single ringing sound event beginning just before the tension record began to rise. The sound event was substantially over by the time the isometric tension began to fall. Results from studies correlating the spatial pattern of the sound, the amplitude and frequency of the sound as a function of the muscle length, and the response of both the passive and active muscle to a transverse pluck were found to be consistent with the conclusion that the sounds in these muscles are caused primarily by transverse resonant vibrations. As the muscle develops force, its lack of cylindrical symmetry gives rise to lateral motions, which are most likely the initiators of the bending vibrations detected as sound.
研究发现，在20摄氏度的盐浴中以等长方式刺激青蛙的腓肠肌时，在张力记录开始上升之前就会产生一个单一的振铃声音事件。当等长张力开始下降时，声音事件基本结束。将声音的空间模式、声音的幅度和频率作为肌肉长度的函数进行关联研究，以及对被动和主动肌肉进行横向拨弦的响应研究，结果均与以下结论一致：这些肌肉中的声音主要是由横向共振振动引起的。随着肌肉产生力量，其缺乏圆柱对称性会导致横向运动，而这种横向运动很可能是被检测为声音的弯曲振动的引发者。
