The influence of temperature on the amplitude and frequency components of the EMG during brief and sustained isometric contractions

Abstract

The influence of temperature on the amplitude and frequency components of the EMG power spectra of the surface EMG recorded over the forearm muscles was examined in five male and five female subjects during brief and fatiguing isometric contractions of their handgrip muscles. Brief (3 s) isometric contractions were exerted at tensions ranging between 10 and 100% of each subject's maximum strength while fatiguing contractions were exerted at tensions of 25, 40, and 70% of their maximum strength. The temperature of the muscles during those contractions was varied by placing the forearms of the subjects in a controlled temperature water bath at temperatures of 10, 20, 30, and 40 degrees C. The results of these experiments showed that the center frequency of the power spectra of the surface EMG was directly related to the temperature of the exercising muscles during brief isometric contractions. During fatiguing isometric contractions, the amplitude of the EMG increased while the center frequency of the EMG power spectra decreased for all tensions examined.

The Short and Long Term Effects of Tibialis Anterior Local Cooling on Dorsiflexion Force

“…Our results demonstrated a positive correlation between temperature and EMG median frequency (Petrofsky & Laymon, 2005;Oksa, 2002;BiglandRitchie et al, 1981). This correlation may be explained by changes in the neuromuscular junctions, as changes in the kinetics of Ca ++ influx and acetylcholine (ACh) binding what may influence the formation of the endplate potential (EPP) (Rutkove, 2001).…”

“…tibialis anterior EMG amplitude behaved similar to dorsiflexion force (Petrofsky & Laymon, 2005).The immediately coolinginduced decrease on dorsiflexion force may be explained by the interaction of many factors that include reduced release of calcium from the sarcoplasmic reticulum and the decline of ATP availability, which impairs the cross-bridge formation (Howard et al, 1994;Douris et al, 2003), impairment in the conduction velocity of muscle fibers (Kimura et al, 2003) and acetylcholine (ACh) binding kinetics (Rutkove 2001). Cross et al (1996) reported an immediately reduction in muscle performance after cooling.…”

“…Local cooling interventions can be carried out using ice packs or immersion in cold water (Van Lunen et al, 2003;Verducci, 2000). When ice packs are applied over the muscle belly it leads to the reduction of skin and muscle temperatures resulting in changes in the Unauthenticated Download Date | 5/10/18 2:36 AM physiological proprieties of the muscle (Castle et al 2006;Petrofsky & Laymon, 2005;Rutkove, 2001). It has been shown that local muscle cooling may influence muscle resistance (Castle et al, 2006;Verducci, 2000) and force production (Oksa 2002;Oksa et al, 1997;Holewijn & Heus, 1992).…”

“…Muscle cooling also reduces sarcolemma conduction, what is reflected by the changes in EMG signal (i.e. decrease of spectral parameters) (Petrofsky & Laymon, 2005;Oksa 2002), and peripheral nerve conduction (Franssen & Wieneke, 1994;Halar et al, 1980), compromising the neural input to central nervous system from muscle receptors. In addition, muscle cooling can affect the contractile apparatus of skeletal muscles (Ricker et al, 1977).…”

“…It is important to note that the different methods of cooling (i.e., ice pack or immersion) may cause different motor output responses, especially because during immersion not only a specific muscle has its temperature lowered but normally several muscles and joints. Immersion has been extensively used in scientific studies (Petrofsky & Laymon, 2005;Douris et al, 2003;Cross et al, 1996;Holewijn & Heus, 1992;Coppin et al, 1978;Johnson & Leider, 1977), but during sports competitions and rehabilitation programs local cooling is much more common (Richendollar et al, 2006;Zemke et al, 1998).…”