MAXIMUM TENSION PREDICTS RELATIVE ENDURANCE OF FAST-TWITCH MOTOR UNITS IN THE CAT
MAXIMUM TENSION PREDICTS RELATIVE ENDURANCE OF FAST-TWITCH MOTOR UNITS IN THE CAT
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DOI：
10.1152/jn.1988.60.4.1215
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发表时间：
1988-10-01
影响因子：
2.5
通讯作者：
COPE, TC
中科院分区：
文献类型：
--
作者：
BOTTERMAN, BR;COPE, TC
本文研究了猫桡侧腕屈肌(FCR)、腓肠肌内侧肌(MG)和一侧指长屈肌(FDL)快抽动运动单位的最大强直张力(P0)、耐力时间和轴突传导速度(CV)之间的关系。耐力时间是指在持续收缩期间，一个单位可以保持25%的最大强直性张力的时间长度。通过计算机反馈控制改变S单位运动神经轴突的刺激率，将运动单位张力“钳制”在最大张力的25%。在单独的实验中，包括研究FDL肌肉的实验，最大张力和耐力时间之间一直存在相反的关系。来自FCR和MG肌肉的汇集数据也导致了最大强直性张力和耐力时间之间的显著相关性。其他研究人员已经表明，最大强直性张力和轴突传导速度与运动神经元的招募顺序高度相关。耐力时间与收缩强度的关系比传导速度更密切。在14个实验中，12个实验中，持续时间与张力之间存在显著的Spearman等级相关，而在14个实验中，仅有3个实验中，持续时间与传导速度之间存在显著相关。
The relationships between maximum tetanic tension (P0), endurance time, and axonal conduction velocity (CV) were investigated in fast-twitch motor units of the cat flexor carpi radialis (FCR) and medial gastrocnemius (MG) muscles, and in one flexor digitorum longus (FDL) muscle. Endurance time was the length of time that a unit could maintain 25% of its maximum tetanic tension during a sustained contraction. Motor-unit tension was "clamped" at 25% of maximum by altering the stimulation rate of a unit''s motor axon through computer feed-back control. In individual experiments, including the one investigated FDL muscle, an inverse relation was consistently found between maximum tension and endurance time. Pooled data from the FCR and MG muscles also resulted in significant correlations between maximum tetanic tension and endurance time. Other investigators have shown that maximum tetanic tension and axonal conduction velocity are highly correlated with the recruitment order of motoneurons. Endurance time was found to be more tightly coupled with contraction strength than with conduction velocity. In 12 of 14 experiments, significant Spearman rank correlation coefficients were found between endurance time and tension, whereas significant correlations were found in only 3 of 14 experiments for endurance time and conduction velocity.