The fatigability of two agonistic muscles in human isometric voluntary submaximal contraction: an EMG study

Abstract

During an external isometric constant torque (25% of the maximal voluntary contraction) maintained until the maximal endurance time (limit time), we analysed and compared the changes in electromyographic (EMG) activity illustrating muscular fatigue simultaneously with mechanical activity (the tangential acceleration theta") related to physiological tremor. The EMG activities recorded were of two agonistic flexors, the biceps brachii (BB) and the brachioradialis (BR) muscles and one of the main extensors, the triceps brachii (TB). The integrated EMG increase and the mean power frequency (MPF) of the power spectrum density function (PSDF) decrease were larger for BR than for BB activity. These two findings suggested a greater BR fatigability. However, it is shown that differences between BB and BR MPF changes could be related to differences in the PSDF upper frequency limit of the two muscles and also to the relative magnitude of their tremor component.

Influence of Force Tremor on Mechanomyographic Signals Recorded with an Accelerometer and a Condenser Microphone during Measurement of Agonist and Antagonist Muscles in Voluntary Submaximal Isometric Contractions

“…2a). This result was consistent with those of previous investigations (Bernardi et al, 1997;Gamet and, Maton, 1989;Psek and Cafarelli, 1993;Ebenbichler et al, 1998), which have also reported a higher EMG amplitude level in the agonist than in the antagonist. It has been reported that the relatively smaller activity of the antagonist increases joint stability (Milner et al, 1995) and prevents excessive force, which could lead to joint damage during muscle contraction (Ebenbichler et al, 1998).…”

“…It is well known that during voluntary muscle contraction the antagonist muscles generate relatively smaller force simultaneously in the direction counter to agonist muscle activity (Smith, 1981;Gamet and Maton, 1989). Therefore, studies that measure and analyze the antagonistic muscle pairs have been performed to evaluate the physiological aspects of muscles (Shibata and Moritani, 1991;Bernardi et al, 1997;Gamet and Maton, 1989;Psek and Cafarelli, 1993;Ebenbichler et al, 1998).…”

“…Therefore, studies that measure and analyze the antagonistic muscle pairs have been performed to evaluate the physiological aspects of muscles (Shibata and Moritani, 1991;Bernardi et al, 1997;Gamet and Maton, 1989;Psek and Cafarelli, 1993;Ebenbichler et al, 1998). Because surface electromyography (EMG) can quantify the activity of antagonistic muscle pairs, EMG has been commonly used as a tool to evaluate agonistantagonist muscle activity (De Vito et al, 2003).…”

Spatial differences in fatigue‐associated electromyographic behaviour of the human first dorsal interosseus muscle.

“…(Rutherford & Jones, 1988;Zijdewind & Kernell, 1994). The interpretation of such electrical tests is, however, complicated by the fact that ulnar nerve stimulation activates FDI simultaneously with its direct antagonist, the first palmar interosseous (Zijdewind & Kernell, 1994 (Edwards & Lippold, 1956); flexor digitorum sublimis held at 25, 50 or 75% MVC (Eason, 1960); biceps brachii and brachioradialis held at 25% MVC (Gamet & Maton, 1989)). Differences between previously published results and the present ones are particularly striking with regard to Fuglevand et al (1993), who also studied FDI and used almost the same fatiguing protocol (contraction held at 20, 35 and 65% MVC).…”

An Exploration of the Effects of Cycle Time and Force Variations on Muscle Fatigue during Submaximal Intermittent Isometric Exertions

“…Such force exertions can either be prolonged, which means the muscular force is continuously sustained, whereas intermittent muscle exertions display variations in the activation levels, including stopping and starting at regular or irregular intervals (Iridiastadi & Nussbaum, 2006). Prolonged static exertions have been widely studied for the development of LMF (e.g., Rohmert, 1960;Gamet & Maton, 1989;Hunter & Enoka, 2003), and the relationship between the endurance time and isometric level of muscle effort is well established. Such exertions are known to result in the fastest onset and greatest development of muscle fatigue, compared to dynamic or intermittent exertions at similar force levels (Bigland-Ritchie & Woods, 1984;SjØgaard et al, 1986;Jonsson, 1988;Masuda et al, 1999;Iridastadi & Nussbaum, 2006).…”