Thermal dependence of muscle function

Abstract

Maximal isometric forces during both twitch and tetanus are largely temperature independent in muscles from both endothermic and ectothermic vertebrates. Anuran muscle can develop maximal force at lower temperatures than mammalian muscle. Tetanic tension is maximal at normally experienced body temperatures in a variety of animals, but twitch tension seldom is. Thermal dependence of twitch tension varies with muscle fiber type: tension decreases with increasing temperature in fast-twitch muscles and remains constant in slow-twitch muscles. In contrast to the low temperature dependence of force generation, rates of development of tension (time to peak twitch tension and tetanic rise time) and maximal velocity of shortening and power output are markedly temperature dependent, with average temperature coefficient (Q10) values of 2.0-2.5 Q10 values for rate processes of anuran muscle are only slightly lower than those of mammalian muscle. High body temperatures permit rapid rates of muscle contraction; animals active at low body temperatures do not achieve the maximal rate performance their muscles are capable of delivering. Thermal acclimation or hibernation does not appear to result in compensatory adjustments in either force generation or rate processes. In vivo, dynamic processes dependent on contractile rates are positively temperature dependent, although with markedly lower Q10 values than those of isolated muscle. Static force application in vivo is nearly temperature independent.

Temperature Effect on the Rates of Isometric Force Development and Relaxation in the Fresh and Fatigued Human Adductor Pollicis Muscle

“…A reduction of maximal voluntary force below muscle temperatures of about 25°C has also been found for other muscle groups in man (Clarke et al 1958;Davies et al 1982;Ranatunga et al 1987) and in animal preparations (e.g. Ranatunga, 1982; for reviews and references see Bennett, 1984;Rall & Woledge, 1990).…”

“…Nevertheless, the effect of fatigue on all parameters decreased with cooling over the entire (37-22°C) temperature range. introduction Temperature is widely recognised as an important determinant of skeletal muscle function (for reviews see Bennett, 1984;Rall & Woledge, 1990). Two important variables with respect to in vivo muscle performance are the rates of force development and relaxation.…”

“…Ranatunga, 1982;K ossler & K uchler, 1987; see also Bennett, 1984;Rall & Woledge, 1990) but data on human muscle are scarce (Wiles & Edwards, 1982;Davies et al 1982;Davies & Young, 1983) and sometimes limited to twitch characteristics (Hopf & Maurer, 1990;Bigland-Ritchie et al 1992) andÏor voluntary effort . It is important to have more detailed knowledge of the temperature effect on the rates of force development and relaxation in human muscle because changes in these parameters could contribute to the temperature dependency of performance found during short-term maximal exercise (e.g.…”

“…The temperature dependence of the maximal rates of force development and relaxation are presented as their temperature coefficient (QÔÑ), where QÔÑ = (RµRÔ¢) (10Ï(Tµ−T 1 )) , in which Rµ and RÔ are rate processes at muscle temperatures Tµ and TÔ, respectively, and Tµ > TÔ (Bennett, 1984). Experimental protocol Single tetanic contractions were elicited with the use of different frequencies of stimulation (1,10,15,20,30,40,50,80,100,150,200 and 300 Hz) applied in random order, with 90 s rest between contractions.…”

“…We can only speculate about the underlying mechanism which could be related to a decreased rate of calcium release andÏor a slowing of net crossbridge attachment rate at low temperatures. Nevertheless, a decrease of isomeric contractile speed has also been found in various animal preparations (Ranatunga, 1982;Elmubarak & Ranatunga, 1984;Bennett, 1984), but quantitative data on human muscle were scarce and incomplete. Ranatunga et al (1987) did not find an effect of temperature (12-39°C) on the rate of tension rise in first dorsal interosseus muscle during voluntary contractions.…”