[Effect of adaptation to hypoxia on the working capacity and energy of skeletal muscles].

The authors studied the working capacity and heat formation of the skeletal muscles during contraction in rats--control and those adapted to hypoxia. The force of contraction, the work and fatigueability of the muscles, as well as elevation of the muscle temperature as a result of contraction were determined under conditions of indirect muscle electrostimulation. Hypoxia adaptation failed to influence the force of muscle contraction and the work performed. However, hypoxia led to reduction of the temperature effect of the muscle contraction per unit of the work performed. This pointed to increase of the efficiency of the muscle work in hypoxia adaptation. Fatigueability of the muscles in "hypoxic" rats was elevated. Changes in the energy of the muscle contraction in hypoxia and cold adaptation were different.