On the basis of the analysis of muscle thermodynamic cycles in terms of the concept of non-equilibrium accumulator of energy some conclusions can be made concerning the character of temperature--entropy relationships. If the redistribution phase proceeds with an essential increase of entropy, the muscle contraction cycle proves to be more advantageous energetically at negative absolute temperatures. If the entropy in this phase gets considerably lower it is more advantageous to realize the cycle in the range of positive absolute temperatures. The non-linearity of ATPase activity which has the maximum in the intermediate phases of contraction leads to the "Maxwell quasidemon" effect and to an increase of overall efficiency.