Colomo F, Lombardi V, Piazzesi G
Dipartimento di Scienze Fisiologiche, Università degli Studi, Firenze, Italy.
Pflugers Arch. 1989 Jun;414(2):245-7. doi: 10.1007/BF00580970.
The tension transients following step length changes imposed on tetanized muscle fibres during the steady phase of force response to lengthening were determined at different velocities. At low velocities the early partial recovery after a step was smaller and slower than under isometric conditions, while the speed of the final total recovery was faster. The degree of depression of the early recovery and the speed of the final recovery increased with the lengthening velocity. At a given lengthening velocity the speed of the total recovery depended on size and direction of the steps, increasing from the region of the larger releases to that of the larger stretches. The changes in the early partial recovery are explained qualitatively by the theory of Huxley and Simmons (1971), while the changes in the speed of the final recovery are explained by assuming that detachment of cross-bridges is negligible until a certain range of cross-bridge strain is reached, and then increases rapidly. It is also necessary to assume that cross-bridges detached in this way re-attach much more rapidly than when they detach on completion of their cycle during shortening.
在对肌肉纤维进行等长收缩力响应的稳定阶段，以不同速度施加步长变化后，测定了强直收缩肌肉纤维的张力瞬变情况。在低速时，步长后的早期部分恢复比等长收缩条件下更小且更慢，而最终完全恢复的速度更快。早期恢复的抑制程度和最终恢复的速度随伸长速度增加。在给定的伸长速度下，完全恢复的速度取决于步长的大小和方向，从较大释放区域到较大拉伸区域逐渐增加。早期部分恢复的变化可由赫胥黎和西蒙斯（1971年）的理论定性解释，而最终恢复速度的变化则通过假设在达到一定范围的横桥应变之前，横桥的脱离可忽略不计，然后迅速增加来解释。还必须假设，以这种方式脱离的横桥重新附着的速度比它们在缩短过程中完成周期时脱离的速度要快得多。
