Homsher E, Mommaerts W F, Ricchiuti N V
J Gen Physiol. 1973 Dec;62(6):677-92. doi: 10.1085/jgp.62.6.677.
The extra heat liberation accompanying muscular shortening, the force-determined shortening heat, is defined as the difference between the heat produced when shortening occurs and that produced in an isometric contraction developing the same amount of force and performing the same amount of internal work. Based on this definition, the initial energy production in twitches and tetanic contractions (E) is given by E = A + f (P, t) + alpha(F)x + W, where A is the activation heat, f(P, t), the tension-related heat (a heat production associated with the development and maintenance of tension), alpha(F)x, the force-determined shortening heat, and W, the external work. It is demonstrated that this equation accurately accounts for the time-course of heat evolution and the total initial energy production in both twitches and tetani at 0 degrees C. The force-determined shortening heat is liberated, during shortening, in direct proportion to (a) the distance shortened, and (b) the force against which shortening occurs. The normalized value of the force-determined shortening heat coefficient, alpha(F)/P(o), is the same in both the twitch and the tetanus. Finally, this formulation of the muscle's energy production also accounts for the total energy production in afterload isotonic twitches at 20 degrees C, where a Fenn effect is not demonstrable.
伴随肌肉收缩产生的额外热量释放，即力决定的收缩热，被定义为肌肉收缩时产生的热量与等长收缩产生相同力量并完成相同量内功时产生的热量之差。基于此定义，单收缩和强直收缩中的初始能量产生（E）由E = A + f（P, t）+α(F)x + W给出，其中A是激活热，f（P, t）是与张力相关的热（与张力的产生和维持相关的热量产生），α(F)x是力决定的收缩热，W是外部功。结果表明，该方程准确地描述了0℃时单收缩和强直收缩中热量释放的时间进程以及总初始能量产生。力决定的收缩热在收缩过程中释放，与（a）缩短的距离和（b）发生收缩时的力成正比。力决定的收缩热系数的归一化值α(F)/P(o)在单收缩和强直收缩中是相同的。最后，这种肌肉能量产生的公式也解释了20℃时后负荷等张单收缩中的总能量产生，此时芬恩效应不明显。
