Skeletal muscles are important components
of the human body that allow us to complete actions that help us move in our
everyday life. Movements such as flexion and extension are all created by
musclular contractions and rely on the coordination and force produced by motor
units (Robertson, 2004). A motor unit is one motor neuron and all the muscle
fibres that are innervated by it (Robertson, 2004). In order for a force to be
produced by a muscle, an action potential must travel down the motor neuron to
the motor endplates and cell membrane of the muscle, also known as the sarcolemma
(L. Bent, personal communication, October 23, 2017).  It is when an action potential is propagated
that all muscle fibres become activated and muscular force is produced
(Robertson, 2004). Additionally, force of a muscle is produced and controlled
by two processes called recruitment and rate coding, where recruitment refers
to activating a large number of motor units in a muscle and rate coding refers
to firing the active motor units more often (L. Bent, personal communication,
October 25, 2017). This is also referred to as spatial and temporal summation
(L. Bent, personal communication, October 25, 2017). The electrical activity of
the muscle tissue that is being produced from these phenomena is referred to as
electromyography, and can be recorded using an electromyogram, also known as an
EMG (Robertson, 2004).