Frequency and conduction velocity analysis of the abductor pollicis brevis muscle during early fatigue

The Influence of Fatigue on Muscle Temperature

“…The greater the external force, the greater the values of bRMS (corresponding to the beginning of the tests) and the lower the values of bMPF. Those results confirmed previous research showing similar relationships [7,8,9,10,20,21].…”

“…Numerous studies indicate the relationship between the amplitude of the EMG signal and the force developed by muscles [18,19,20,21]. Moreover, many studies confirm the influence of the level of muscle load on the values of the parameters characterizing the power spectrum of the EMG signal [6,7,8,9,10] and indicating muscle fatigue. Thus, it can be assumed that EMG is a method suitable for assessing muscle fatigue.…”

“…This method makes it possible to estimate fatigue on the basis of the electrical signal registered from muscles during their activation [3,4,5,6,7,8,9,10,11,12]. The registration of an electrical signal with surface electrodes is commonly used to assess muscle load and fatigue during occupational tasks [13,14,15,16,17].…”

Does central fatigue exist under low-frequency stimulation of a low fatigue-resistant muscle?

“…This observation can be explained by the nature of the studied muscle. The APB muscle is a low fatigueresistant muscle (Barandun et al 2009), and these muscles are known to be more sensitive to failure of muscle excitability (Pagala et al 1984). Our results indicate that changes in sarcolemmal excitability are not only dependent on the stimulation frequency, as previously suggested (Badier et al 1999;Zory et al 2005), but are also influenced by other factors, like muscle fatigability.…”

“…We took into consideration the results of a previous study, which showed that intermittent low-frequency stimulation of the triceps surae provoked early central command failure without any impairment at the spinal or peripheral level (Papaiordanidou et al 2010), and examined the physiological alterations, both qualitative and temporal, obtained when the same ES protocol was applied to a low fatigueresistant muscle. The abductor pollicis brevis (APB) muscle was chosen because it is known to be highly fatigable (Barandun et al 2009). Independently of its reported fiber typology (60% of type I fibers; Johnson et al 1973), the APB is a small, weak muscle with low resistance to fatigue (time to exhaustion at 50% of maximal force *3 min; Duchateau et al 2002).…”