Cooper P G, Wilson G J, Hardman D T, Kawaguchi O, Huang Y F, Martinez-Coll A, Carrington R, Puchert E, Crameri R, Horam C, Hunyor S N
School of Indigenous Australian Studies, James Cook University, Queensland, Australia.
Med Biol Eng Comput. 1999 Jul;37(4):451-5. doi: 10.1007/BF02513329.
Experiments are described in which a fatigue index is determined for the latissimus dorsi muscle of sheep in situ, using capacitive strain gauges. Parallel experiments for invasive and non-invasive measurements are conducted, measuring global contraction and relaxation rates and shortening duration for paced muscle. The results show that, above one pulse per burst (5 V, 100 microseconds pulsewidth), contraction rates (62 +/- 11 mm s-1) and relaxation rates (50 +/- 7 mm s-1) are constant for unloaded muscle. For one animal, fatigue testing with a 2.5 kg load at six pulses per burst shows shortening rates increasing to a maximum (80 mm s-1) after 30 s and reducing to 5 mm s-1 after 150 s. The decrease in shortening amplitude is used as a fatigue index, log displacement against time. Power output is load dependent, measuring 4.7 W kg-1 with a 2.5 kg load. There is good agreement between the invasive and non-invasive measurements, thus providing a method for monitoring changes in muscle parameters non-invasively during future pacing transformation.
本文描述了一些实验，其中使用电容式应变仪在原位测定绵羊背阔肌的疲劳指数。针对侵入性和非侵入性测量进行了平行实验，测量了有节奏刺激肌肉的整体收缩和舒张速率以及缩短持续时间。结果表明，在每次爆发一个以上脉冲（5V，100微秒脉冲宽度）时，无负荷肌肉的收缩速率（62±11毫米/秒）和舒张速率（50±7毫米/秒）是恒定的。对于一只动物，在每次爆发六个脉冲、加载2.5kg负荷的疲劳测试中，缩短速率在30秒后增加到最大值（80毫米/秒），并在150秒后降至5毫米/秒。缩短幅度的减小被用作疲劳指数，即位移对数相对于时间的变化。功率输出取决于负荷，在2.5kg负荷下测量值为4.7W/kg。侵入性和非侵入性测量之间有良好的一致性，从而为未来起搏转换期间非侵入性监测肌肉参数变化提供了一种方法。
