[Economy of muscle work in an unfused tetanus setup]

For the estimation of the economy of muscle contraction the intramuscular temperature was measured during sustained unfused isometric tetanus of m. flexor digitorum sublimis. Experiments were performed with the local blood arrest. The records of tension were compared with the heat production at the same time. The rate of temperature rise is maximal in phase 2 (the period of largest force oscillations). The economy of muscle contraction in this phase is 1,3--1,7 times lower than at the beginning of the tetanus. The peak of heat production takes place at the 10--15 sec of contraction. After that muscle economy increases progressively and to the 40--50 sec of tetanus reaches the final level, which is in average 3,5 times higher than initial one.