Skeletal muscle fatigue in vitro is temperature dependent

Abstract

Our purpose was to determine the effect of temperature on the fatigability of isolated soleus and extensor digitorum longus (EDL) muscles from rats during repeated isometric contractions. Muscles (70-90 mg) were studied at 20-40 degrees C in vitro. Fatigability was defined with respect to both the time and number of stimuli required to reach 50% of the force (P) developed at the onset of the fatigue test. Fatigue was studied during stimulation protocols of variable [force approximately 70% of maximum force (Po)] and constant frequency (28 Hz). Results for soleus and EDL muscles were qualitatively similar, but fatigue times were longer for soleus than for EDL muscles. During the variable-frequency protocol, development of approximately 70% of Po required an increase in stimulation frequency as temperature increased. During stimulation at these frequencies, fatigue time shortened as temperature increased. For both fatigue protocols, the relationship between temperature and the number of stimuli required to reach fatigue followed a bell-shaped curve, with maximum values at 25-30 degrees C. The temperature optimum for maximizing the number of isometric contractions to reach fatigue reflects direct effects of temperature on muscle function.

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

“…This finding is in accordance with the observation that at low temperatures energy cost of isometric force generation is reduced and this might be expected to delay the onset of fatigue (Rome & Kushmerick, 1983;Biewener et al 1983;Rall & Woledge, 1990;Stienen et al 1996). Indeed, cooling has been found to increase time to fatigue in repetitively stimulated isolated rat muscle (Segal et al 1986), although others did not find a temperature effect on fatigability (Blomstrand et al 1985;L annergren & Westerblad, 1988). During voluntary sustained effort maximal endurance times have been reported at intermediate (27-33°C) muscles temperatures with an increased fatigability at lower (and higher) temperatures (Clarke et al 1958;Edwards et al 1972).…”

“…A factor that presumably contributes to this enhanced fusion of force at low frequencies of stimulation is an increased calcium sensitivity of the thin-filament regulatory system at low temperatures (Stephenson & Williams, 1981, 1985. Similar leftward shifts of the frequency-force relationship with decreasing muscle temperature have been reported for isolated rat (Ranatunga, 1982;Segal et al 1986) and cat muscle (Petrofsky & Lind, 1981).…”

“…Besides a decrease of fatigue with decreasing temperature in rat muscle (Segal et al 1986), a musclefibre-type-dependent optimum temperature for sustainable force has been reported for cat muscles (Petrofsky & Lind, 1981), whilst others have found fatigue to be unaffected by temperature during repetitive isometric activation of isolated muscle (Blomstrand et al 1985;L annergren & Westerblad, 1988). Moreover, there are only a few studies on human muscle fatigability under isometric conditions at different temperatures and most of these studies were on voluntary submaximal sustained contractions (e.g.…”

Measurement of contractile force of skeletal and extraocular muscles: Effects of blood supply, muscle size and in situ or in vitro preparation

“…An important criterion in maintaining muscle viability is muscle thickness. For skeletal muscle the critical muscle thickness or diameter at different incubation temperatures is well established (Segal and Faulkner, 1985;Segal et al, 1986;Bonen et al, 1994). Based on these criteria, an incubation temperature of 35°C, as used in our study, requires that the skeletal muscle thickness should be ≤ 1.25 mm in order to maintain adequate oxygenation (Segal and Faulkner, 1985).…”

The interactive effect of cooling and hypoxia on forearm fatigue development

“…Several studies report that action potential propagation, ATP hydrolysis, Ca 2+ handling and sensitively as well as cross-bridge force kinetics are adversely affected by lower tissue 3 temperatures (Kossler et al 1987;Sweitzer & Moss 1990;Mucke & Heuer 1989;Feretti 1992;Oksa et al 2002Cè et al 2012. However, the slowing of mechanical processes, as well as efferent and afferent nerve conduction, occur independently of exercise (present during passive cold exposure), and thus may even serve to attenuate metabolite production, and/ or increase central drive, during prolonged isometric contractions (Ray et al 1997;Segal et al 1986;De Ruiter & De Haan 2000;Todd et al 2005;Allen et al 2008;Cahill et al 2011;Lloyd et al 2014). Nevertheless, during dynamic exercise in cooled muscle (i.e.…”