Investigation and analysis of low frequency of electromyogram during isometric contraction

Neuromuscular control consists of central command and the peripheral neuromuscular system (PNS). The PNS has a feedback loop and consists of the spindle receptors that respond to the stretch of the muscle and is responsible for maintaining steady contraction. Stretch reflex is commonly used to determine the properties of the PNS, and the stretch reflex latencies are attributable to the neural delays. While the importance of spindle feedback in muscle control has been hypothesised and reported, no significant research has been conducted to study the relationship of neural delays and muscle activity. This paper presents a study to test the hypothesis that the neural delays in the PNS are the cause of modulation of the electrical activity of the muscle. While the continuous variation of surface electromyogram (sEMG) during isometric contraction has been previously observed, and the amplitude of this variation has been studied, the time constant associated with this variation has not yet been studied. This paper proposes the hypothesis that the time constant of the variation of sEMG during isometric contraction is associated with the neural delays in the PNS.