Maton B
J Physiol (Paris). 1977 Jul;73(2):177-99.
The recruitment and the changes in firing frequency of biceps brachii motor units (MU) were studied during static work in normal man. The activity of single MUs have been followed from minimal to maximal levels of force, using three selective wire-electrodes inserted in the muscle. 1. The increase of MUs firing rate contributes to the force increase during the whole of the range of forces. However, the contribution of increased firing rate is more important at low force levels. 2. The firing rate variability is more important for low levels of force. This may be one of the mechanisms by which the summation of the twitches leads to a stable contraction. 3. At each level of force, the diverse MUs fire at the same mean frequency, except during the "catching up phase" which follows the start of the 'MUS activity. 4. The force generated by the muscle varies linearly with the number of active MUs, i.e. the MU recruitment has a constant contribution to the increase of force. 5. The comparison between firing rate and MU recruitment suggests that the first mechanism is more important f or low levels of force, while MU recruitment becomes more important at higher force levels.
在正常男性静态工作期间，对肱二头肌运动单位（MU）的募集情况及放电频率变化进行了研究。使用插入肌肉的三根选择性线电极，追踪单个运动单位从最小到最大力量水平的活动情况。1. 在整个力量范围内，运动单位放电频率的增加有助于力量的增加。然而，在低力量水平时，放电频率增加的贡献更为重要。2. 对于低水平的力量，放电频率的变异性更为重要。这可能是抽搐总和导致稳定收缩的机制之一。3. 在每个力量水平上，除了运动单位活动开始后的“追赶阶段”，不同的运动单位以相同的平均频率放电。4. 肌肉产生的力量与活跃运动单位的数量呈线性变化，即运动单位的募集对力量增加有恒定的贡献。5. 放电频率与运动单位募集之间的比较表明，第一种机制在低力量水平时更为重要，而在高力量水平时，运动单位募集变得更为重要。
