Final answer:
Muscle artifact voltages in skeletal muscles can be consistent or erratic in amplitude and frequency. The tension produced in skeletal muscle is influenced by the frequency of action potentials from motor neurons. When the frequency of motor neuron signaling increases, muscle tension can rise until it reaches a peak point.
Step-by-step explanation:
Muscle artifact voltages can sometimes be consistent or erratic in amplitude and frequency in skeletal muscles. This is because the tension produced in skeletal muscle is influenced by the frequency of action potentials (nerve impulses) from motor neurons and the number of motor neurons transmitting action potentials. When the frequency of motor neuron signaling increases, muscle tension can rise until it reaches a peak point, resulting in a state called incomplete tetanus.